# Replacement of carbide lamps by LED lamps



## Tobias Bossert

*Replacement of cavers carbide lamp by LED lamps*

1.Purpose of this treat
2.Development of a headlamp optimized for caving
3.Amount of light required
4.Color temperature and beam pattern
5.Batteries and electronics
6.Optics and housing

*1.**Purpose of this treat*

Candlepowerforums is substantial work, sometimes too extensive to find exactly what you need. The purpose of this treat is to bring together all those information required to develop an optimized headlamp for utilization in caves.

I start this treat with a lot of additional information and hope, that I can learn from feedback and proposals the members of Candlepowerforums can give me.

I’m member of a cavers club in Austria. We plan to build our own headlamps for our club but not to sell them: we have *NO* commercial interest. But we think the ‘high tech’ products from www.lupine.de and www.scurion.ch are much too expensive for hobby cavers, so one aim is to develop cheep but never the less optimized alternatives.

*2.**Development of a headlamp optimized for caving*

When I started my first expedition into a big alpine cave in 1965 I used a carbide hand lamp, as usual at that time. In those days it was impossible to achieve sufficient light output with battery flashlights for expeditions of several days. In the early 1970s cavers changed to carbide headlamps. Up to now most cavers still use carbide lamps, since these are extremely reliable, easy to maintain and provide sufficient light even for large rooms in big caves. Duration of expedition doesn’t matter, its a question of amount of carbide you take along (about 400g per day).

Since some years, many manufacturers provide battery headlamps based on white LED. Unfortunately none of them really comply with what is required during a several days cave expedition. But indeed the technology is advanced enough to develop a headlamp satisfying these requirements.

*3.**Amount of light output required*

The old lamps e.g. combine up to 250g of carbide with about 140g of water to produce an amount of 100g acetylene (~ 100 liters). Four sizes of burners are used commonly, consuming 7, 10, 14 or 21 l/h of acetylene. The flame delivers about 67, 92, 133 or 200 lm at a color temperature of about 2300K. The burner alone would throw a nearly isotropic pattern, only downwards a cone of about 60 degree is shaded by the burner itself. The burner is mounted in front of the helmet and uses a small reflector. During normal use, this reflector gets blackened quickly, so about 60% of the light can be used only. Most cavers in Europe use burners with 14 or 21 l/h providing a total luminous flux of about 80 to 120 lm. These lamps consume about 33 to 50 g/h of carbide. But the carbide lamp itself has an overall weight (carbide/water-container plus tube plus head lamp) of another 1000 g too.

It would be nice to get the same total luminous flux from the new technique too. 

Actual white LEDs are promoted to deliver 100 lm/W. That’s not true. The following table demonstrates the achievable luminous output of four actual types off SSC P4.






*Table 1 – Achievable luminous output with actual white SSC P4 LEDs *

The electrical power required to replace the good old carbide lamp depends. Carbide lamps deliver a rather uniform spatial pattern, thus you have to compare with bare LED covered by plain glass only. In the worst case using the S_42182_S_SS0_I to replace a burner with 21l/h you will need 3,2 W drawn from the battery and in the best case using the W_42182_U_SVN_I to replace a burner with 14 l/h you will need 1,3W.

So ‘paulr’ https://www.candlepowerforums.com/posts/2176679&postcount=2 was right with his estimations!

First thought: take SSC U bins, they are brightest! Really?

*4.**Color temperature and spatial pattern*

We are not interested in the physiological sensation looking directly into the light source but rather in the amount of light being reflected from the objects we want to see. SSC U bin covers equivalent temperatures from 4500 to 7000K, quite different from our used carbide flame having 2300K. The reflection factor of typical materials found in caves depends on wavelength. Bluish materials are rare, e.g. loam is rather beige. Therefore it might be possible, that the “bright” U bins with 6700K subjectively will be less bright inside a cave than an objectively less bright S2 bin with 3000K.

_Color temperature_

First I tested those five LED types given in table 1 at home. Against a pure white wall indeed all U bins are the brightest subjectively. Against a wall colored with ‘apricot white’ the S bin with 4000K subjectively seems to be at least as bright as the best U bin, in this case 5300K. Against a pine wood ceiling, the S2 bin with 3000K appears brightest.

Studies are carried out in alpine caves at the moment to determine the subjectively brightest LED type amongst those of table one. The tests cover both, plain LED (uniform spatial pattern) and narrow beam (10 deg), because it is not determined in advance, that the findings will be the same. I will supplement the results when finished!

>> Questions to everyone: 
Are there better LEDs out for 3000 to 4000K than SSC P4 bin S and S2?
Where can I buy W_42182_U_SUN_.. or ...SUM..., that’s 4500 to 5000K and nevertheless U bin?

_Spatial pattern_

The carbide lamp didn’t allow realizing a narrow beam. This is one significant improvement using LED technique, now you can look down into deep pits too. But during walking and climbing inside a cave, you rather would prefer uniform spatial pattern than any beam. Everyone who ever tried to make a night walk with a beam lamp knows what I mean: You either risk stumbling or you will get a stiff neck! Therefore the new electric headlamp should provide both, all-round light (covering hemisphere in front of you) and spotlight (as narrow as achievable), switched alternatively.

*5.**Batteries and electronics*

In October 2007 I started the project and asked the members of candlepowerforums for applicable converter boards for my project. But this was on the wrong forum I think (flashlight electronics – batteries included). Now I can demonstrate three practical solutions, cheep, efficient and optimized for cavers headlamps. But the optimum solution depends upon the battery type to be used.

_Batteries_

Professional ‘high tech’ headlamps use Li-Ion rechargeable batteries. This is the best solution technically: Li-Ion provide the highest energy density (more than twice of alkaline and Ni-MH) and are able to deliver high drain currents even at low temperatures. But the problem arises from cavers negligence: They use the lamp until it gets dark and after the trip all the stuff ends up in the cellar, neither being cleaned nor recharged – this normally will be made up for 15 minutes before starting to the next expedition. Therefore I decided not to propose them to use Li-Ion rechargeable batteries.

The second-best solution would be Li-FeS2 primary batteries. But if you start remembering your stuff just some hours in front of leaving to the trip and have not enough batteries at home, you will fail, because there is no shop providing these strange batteries on the way to the cave.

Alkaline batteries would be the most practical solution in my mind. They are extremely cheep and available everywhere. But the characteristic of alkaline cells depends strongly upon the cell size! As you can derive from the studies of ‘Silver Fox’ https://www.candlepowerforums.com/threads/64660 the realistically achievable energy density of alkaline cells drained with low to medium currents is nearly independent of the cell size (50 to 90 Wh/kg depending on brand). This doesn’t surprise because the chemistry is the same for small and large cells. But the realistically achievable power per weight is much higher with smaller cells (AA-size above 20 W/kg but D-size below 8 W/kg only). Thus it makes more sense to use 6 AA cells than 1 D cells having the same weight.

The achievable energy depends upon the power drained: the heavier the load, the smaller the drainable energy content. I made two tests in my household refrigerator: two battery packs (6 AA and 8 AA in series) were discharged with 1,5 W continuously down to 3,5V. This means, the first pack is loaded by 0,25 W and discharged to 0,6 V each cell and the second pack by 0,188 W and to 0,45 V. The weight of the second pack is 133% of first one, but delivers 142% of total energy. My conclusion is that these additional two cells could be carried much more comfortable in the backpack than in battery belt at the helmet or worn in the chest pocket!

At the end I decided to propose using batteries of AA size. Most cavers I know will use alkaline types which you can purchase at every supermarket. But the electronics will also accept Li-FeS2 primary and Ni-MH rechargeable batteries of AA size too.

As estimated above, at least 1,3 W will be required continuously to get an equivalent luminous flax as a carbide lamp. Inside alpine caves temperatures are about 0 to 6°C. Under such circumstances alkaline AA cells deliver about 1,5 to 2,2 Wh when drained with less than 250 mW continuously and if the converter board allows to unload the cells completely. Rough estimation: average cell consumption will be 0,7 to 1 cell per hour when using at least 6 cells in a battery pack. For a 9 hours trip with continuous light you will waste 6 ‘good’ or 9 ‘cheep’ AA alkaline batteries. The consumption expressed in weight is about 18 to 25 g/h. Remember: this will replace 33 to 50 g/h of carbide consumption, a reduction of 50%! And the device itself is much lighter than the carbide lamp too. Additionally we can hope LED efficiency still will increase in future ...

_Electronics_

We need thee levels of output current:
Working light, about 350 mA, used continuously all over the day
Pause light, below 35 mA, used during breaks
Spot light, amara (as much as realistically achievable) used only for short term

First I tested some of those multi mode buck converter boards from Kaidomain and DealExtreme. But I came back to the single mode types, because these are more flexible for my own modifications. At the end three boards are shortlisted: Taskled CC1W, Kaidomain sku.2982 and Dealextreme sku.3256. All three easily can be modified to match the requirements of cavers headlamps.

Taskled CC1W

By far this is the best board tested, but also the most expensive too ($15 + shipping). It has excellent manufacturing quality and George gives extensive support, answering your questions spontaneously! This board also provides the best efficiency. The output current can be varied by paralleling resistors to R2 or R3 labeled on the board.

I provide you with measured curves for three modes, each of them with shortened polarity protection diode:
Blue – original board (no resistors in parallel) => I = 350 mA, average efficiency 88%
Green – dimmed down with R2 || 560 ohm => 35 mA, average efficiency 72%
Red – boosted with R3 || 180 kohm => up to 620 mA, average efficiency 87%





*Figure 1 – Characteristics of Taskled CC1W*

Original and dimmed current is regulated constant. Boosted current would calculate to 670 mA, but the internal current limiter supersedes and the output current depends upon supply voltage. This is no disadvantage because it makes no sense to demand a boosted current from nearly discharged alkaline batteries. This board accepts supply voltages up to 20V.

Kaidomain sku.2982

This medium priced board ($ 3,10, free shipping) also has a good manufacturing quality but its efficiency suffers at higher current levels. This board accepts supply voltages up to 18V. Fortunately this board is now available again.

Originally the board delivers 750 mA, always o.k. for our boost mode. To reduce output current you will have to unsolder pin 8 (FB) of the integrated circuit PT4105 and insert a resistor (I took 1,8 kohm). With an additional resistor of 56 kohm from FB to LED+ you will get about 350 mA output current, and with about 25 kohm (depends upon Vf of LED) you achieve 35 mA.





*Figure 2 – Characteristics of Kaidomain sku.2982*





*Figure 3 – Application of Kaidomain sku.2982 for cavers headlamp*


DealExtreme sku.3256

This low priced board ($ 1,61, free shipping) has poor manufacturing quality only but its efficiency is good. This board is specified for 1 A output current, but the current is unregulated and depends upon supply voltage and Vf of LED.

Before you start modifying the output current of this board, you should solder ceramic SMD capacitors in parallel to these strange aluminium electrolytic capacitors, this will increase the efficiency by about 3% (I tried 2,2 or 4,7µF 16V).

To reduce output current you will have to unsolder pin 4 (ISENSE) of the integrated circuit C300 and insert a resistor. This resistor should range below 100 ohm, because it is in the rf path (I took 39 ohm SMD type and soldered it on empty place “R2” after having cut the lower connection of it to IN-).

With an additional resistor from ISENSE to ground (IN-) you can divide the sensed voltage and thus increase the output current. With an additional resistor from ISENSE to supply voltage (IN+) you can decrease the output current. But the effect of this manipulation depends upon supply voltage and therefore rotates the output current curve over input voltage clockwise. If you connect the resistor to LED- instead, this rotation will be even stronger. Choosing the optimum relation between resistors to IN- and to IN+ or LED- you can achieve a nearly flat response.

With resistors of 27 kohm from ISENSE to LED- and of 220 ohm to IN- you will get about 1 A output current almost constant over an input voltage from 4 to 9V.





*Figure 4 – Characteristics of DealExtreme sku.3256 for high current level*

The current spikes in these curves occur when the device transfers from direct mode to switching mode and vice versa. The arrows show the different dynamic behavior for increasing and decreasing supply voltage. The arrows would be vertical with zero source impedance and horizontal with a pure current supply. During use with alkaline batteries you will not encounter these peaks, because the impedance of nearly discharged batteries is too high.

1 A is not of interest for our project since we require lower currents. It is impossible to decrease the output current much below 100 mA using the original current measurement resistor of 0,020 ohms. You need to unsolder it and replace it by a higher value (I used 0,150 ohm). With this you can achieve flattened curve at 350 mA and 35 mA as demonstrated in the application. In this application the boost level intentionally is not flattened.





*Figure 5 – Application of DealExtreme sku.3265 for cavers headlamp*





*Figure 6 – Characteristics of DealExtreme sku.3256 used for cavers headlamp*

The disadvantage of this board is the limited input voltage. Therefore the battery pack is limited to 6 alkaline cells in series or to 7 Ni-MH.

*6.**Optics and housing*

Mechanical manufacturing seems to provide more problems than electronics!

_Optics_

Most actual white LED provide a dome with a week spatial concentrating. This is fine for working and pause light and needs no additional optics which would cost 15 to 25% of light anyhow. But at least you will need a plane of glass to protect the LED and the starboard. Even this will cost about 10% of emitted light and restrict the spatial pattern to about 150° (original is 180°). It would be preferable to use a transparent spherical cap, comparable to http://www.khatod.eu/pdf/pljt20_test_report.pdf but not opalescent. 

>> Questions to everyone: 
Where can I buy such transparent caps?

For spot light we need a reflector or lens optic with low losses, narrow beam and low stray light around the spot. Most of all miniature plastic optics don’t comply with this. The best results so far were achieved with Gaggione LL3 http://www.lednlight.com/LL3.htm, in German forums sometimes called ‘Mobdar’ but as far as I can see, these are from different sources. Unfortunately this collimator needs small modification to allow optimum placement of SSC P4 LED.

>> Questions to everyone: 
Is there any better optics for SSC P4 LED on the market?

_Housing_

The headlamp mounted at the helmet contains two parts, one for spot light and another one for working light. Spotlight will be similar to http://default.nueb.de/fahrrad/licht/mueller/ but with smaller heat sink. The other one may be a short aluminium tube (diameter 25 mm) covered by a plane of glass at front side and by a small heat sink in the back.

At the moment four arrangements are under discussion:





*Figure 7 – Four alternative arrangements of battery box and headlamp*

Arrangement a)
Electronics, both switches and spot light mounted in the battery box; headlamp contains all-round light only; minimum weight and size mounted at helmet.
Headlamp diameter 25mm, length 15 mm
Cable with two wires only
Battery box in the chest pocket 140 x 60 x 20/25 mm; spot light with diameter 40 mm protruding 5 mm out of the flat side; switches and cable outlet flush mounted at the smallest side
Problem: How to protect spot during crawling?

Arrangement b)
Electronics and both switches mounted in the battery box; headlamp contains all-round light and spot light; all switches still safe in the pocket; spot light follows movement of head.
Headlamp diameter 25mm, length 25 mm plus diameter 40mm, length 25.
Cable with three wires.
Battery box in the chest pocket 120 x 60 x 20 mm; both switches and cable outlet flush mounted at the smallest side; alternatively one rotary switch instead of two toggle switches.

Arrangement c)
Electronics and only main switch mounted in the battery box; headlamp contains all-round light, spot light and switch to choosing amongst all-round and spot light.
Headlamp diameter 25mm, length 25 mm plus diameter 40mm, length 25.
Cable with three wires.
Battery box in the chest pocket 120 x 60 x 20 mm; main switch (work-off-pause) and cable outlet flush mounted at the smallest side.

Arrangement d)
Only batteries in the battery box; headlamp contains all-round light, spot light, electronics and both switches.
Headlamp diameter 25mm, length 25 mm plus diameter 40mm, length 25 plus diameter 25mm, length 25 mm (containing electronics).
Cable with two wires only.
Battery box in the chest pocket 100 x 60 x 20 mm; if desired, battery could be changed together with battery box.

In any case the battery box is required to be solid enough to accept the barer rests on it at a stony subgrade. The headlamp is required to be solid enough to accept knocking one’s head against the roof. Both parts are required to be waterproof. 

At the moment nothing mechanical is realized; I’m happy not to be the one having to develop this!


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## SilverFox

Hello Tobias,

Welcome to CPF.

This looks like quite a project...

If I may comment on your selection of batteries.

In the conditions you are going to be using the light, the optimum, in my opinion, power supply to use would be the CR123 primary lithium battery. I don't know how many are in your club, but you could put in a bulk order and have ample cells to power your light.

I would suggest you explore using 2 of the CR123 cells in series. Back up power could be supplied by a 9 volt battery, if your circuit would allow that, and you could also utilize a 4 AA battery holder for those who like to carry extra weight...  or for the use of the Energizer L91 battery.

Alkaline AA cells work well in the 5 - 10 C temperature range, but it has been my experience that once the temperature drops below 5 C, you need to make provisions to warm your batteries, including your spares.

Good luck on your project.

Tom


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## cave dave

your pictures are over the size limit


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## yellow

please, first of all !!!
make the pics smaller, so that one does not have to scroll sideways to read that whole post
(I came to 2/3 till got bored and only answer to that parts)


several points to consider:
* try to find the *TINT* of the led You like, not the BIN, thats of prime importance.
* forget the Seouls and use Crees
* being picky on normal prices for circuits (15,-- being expensive ) is no use for Your applications.
* I have seen carbides in caves - there will never be a more appealing short distance area light 
(possibly try sunny white 5mm leds for this)
* _working light _@ 350 mA - thats the power my headlamp runs on --> for running and biking. WAY too powerful and unnecessary for normal caveing use imho

the best TINT-showing tread on CPF: https://www.candlepowerforums.com/threads/156772


wenn Euch das interessiert (because _Austrian_ cavers club), kann ich Euch ja mal ein paar meiner gemoddeten Lämpchen zeigen, damit Ihr nen Eindruck bekommt - wenn Ihr Euch in Wiennähe trefft (befinde mich selbst in Baden),
oder kommt mal zu einem Nightride (gepostet auf bikeboard.at)


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## yellow

phuaa, now got the whole post - good luck on the project, it sure has arleady given You quite some thoughts, right?

I read all the usual bad things (what I consider as bad) where ppl make themselves unnecesary probs and new ones with every problem solved (starts with wanting to produce ones own light head, ...)
Better find Yourself a flashlight that can do what You want except of runtime, then _use just its head _and make someting to connect the batts with it.
Or find a cheap light You like from its looks on DX (You know the site already), put the led You like inside, circuit behind, add end plate and method of mounting to housing, connect to batt pack --> ready, including a nice housing, front glass, rubber O-rings, ..., with less work a homemade housing will give


the part I can totally not understand is how the lights, possibly the whole equipment, is cared and prepared for after and before the uses. Anyway, there is Li-Ion only for You, a pack made from 4 pc. of 18650 will cover at least 20 hours of the 350 mAh draw.
read more here
(I would still mod it a bit, f.e. this protection circuit instead of that large Bratbeck, but ...

or get a light that is meant for 2 pc. CR123a, use just its head and have it run with 7.2 V Camcorder batts - which should ease recharging as most ppl have one.

... You main problem will be that most light are aimed on brightness - I see no chance You can do with without modding something
PS: did I already mention to use Crees instead of the blue Seouls? 


[edit]
Question: how hard is that temperature problem? Thought cavers wear the batts strapped to the body under the outer clothing? Isnt that a higher temp then?
Anyone of You uses the common Petzl led models or other commercial led headlamps? Do You all agree on to change to led? (even when only knowing the Petzls?)  [/edit]


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## Tobias Bossert

yellow said:


> PLEASE, FIRST OF ALL !!!
> make the pics smaller, so that one does not have to scroll sideways to read that whole post




Uups!
I sized the pics to 1200 pix maximum width. This works fine on a screen with 1280 pix width and with browser settings not consuming more than 80 pix on left and right.

Now I have reduced the pics to a width of 950 pix, this should be visible completely even with a screen width of 1024!

Please don't forget to empty your browsers cach befor reloading the page, because otherwise you will not see any difference.

This is no good solution, that there is no autoscaling managing this: So all users have to restrict to the reader with the most narrow screen...


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## Tobias Bossert

yellow said:


> * _working light _@ 350 mA - thats the power my headlamp runs on --> for running and biking. WAY too powerful and unnecessary for normal caveing use imho




Hi yellow,
i'm used to caving since more than 40 years now! Let me say, there are many halls in caves where you blow water into your carbide lamp to increase the flame, but nevertheless it's still too week.
But even with the normal pressure produced by the water in the tank above the carbide the lamp gives about 80 to 120 lumens all the time. To output 100 lumens from a LED lamp you need more than 350 mA at present, don't forget the losses in the headlamp (glass).
In caves I frequently pass along tunnels more than 10 m broad, and you realy mean that 350 mA is WAY too powerfull? - It isn't!
And last but not least: I'm used to have this amount of light in caves for many years and will not reduce my demands now. 
Kind regards
Tobias


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## Jarzaa

Tobias Bossert said:


> Are there better LEDs out for 3000 to 4000K than SSC P4 bin S and S2?



Here are warm white Q2-bin Cree leds that produce at least 87.4lm with 350mA
http://www.led-tech.de/en/High-Powe...CREE-XR-E-7090-Q2-Emitter-LT-1064_120_77.html
At that site you can also find Seoul and Lumileds leds. For maximum light output but with high color temperature i would recommend to use Q5 bin Cree XR-E leds instead of the Seoul leds.


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## SilverFox

Hello Tobias,

I need to point out that the forum rules state that the maximum picture size is restricted to 800 X 800. You are close, but you need to shrink them down just a little more.

Thanks.

Tom


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## Tobias Bossert

Jarzaa said:


> Here are warm white Q2-bin Cree leds that produce at least 87.4lm with 350mA



Thank you very much! 
Indeed this warm white Cree XRE WHT-L1 5C Q2 is really "warm" (5C = 3700 to 4000K) and much brighter (87 to 93lm @350ma) than everything from SSC in warm or natural white. I'll try them out immediately!
The other LEDs XRE WHT-L1 WG Q5 you mentioned are too "cool" (WG = 5700 to 6200K), but you are right, they are brighter than the comparable SSC P4 with U luminance.
I'm still looking for SSC USUM or USUN (4500 to 5000K), but may be your warm white Cree will be the winner!
Kind regards
Tobias


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## Tobias Bossert

SilverFox said:


> Hello Tobias,
> 
> I need to point out that the forum rules state that the maximum picture size is restricted to 800 X 800. You are close, but you need to shrink them down just a little more.
> 
> Thanks.
> 
> Tom



SilverFox, 
sorry, indeed I violated the forum rules. 
Now all pictures are max. 800 wide. Is it necessary to formerly reduce the size of some pictures, because the pictures containing two combined diargrams are still higher than 800 pixels?
Please give me advice in case I should also reduce the hight of all these diagrams to 800 pixels.
But in this case I should rearange the pictures because the photos and circuitdiagrams mounted into the measurement curves will no more be recognizable.
Sorry for the trouble I make to you. I will learn and next time avoid such big pictures.
Kind regards
Tobias


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## SilverFox

Hello Tobias,

There has been some discussion amongst the administration if we could make exceptions for graphs. However, this is still in discussion and as it stands right now, the rules state a maximum of 800 X 800.

Thank you for your cooperation.

Tom


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## Tobias Bossert

SilverFox said:


> Hello Tobias,
> There has been some discussion amongst the administration if we could make exceptions for graphs. However, this is still in discussion and as it stands right now, the rules state a maximum of 800 X 800.
> Thank you for your cooperation.
> Tom





done now!


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## yellow

looks like we typed to different topics ...

- for the "walk around use" the 350 mA for the headlamp is very bright,
The mountain guide (which I asked to lead us because there were some 1st timers around) had his Aceto running and that 5 meter 360 degrees area light was just great. Dont think anything can make a similar nice light.
for distance work it was useless (You know that already) 
- for looking at larger distances (better a handheld lamp application?), even my Cree @ 1 A seemed too dim (this summer while visiting the Frauenmauerhöhle), but it was by far the strongest light of the group.

There is also some other thing that can be annoying, especially with Led-headlamps (compared to the Acetos): being more focused, one tends to blind the person to talk to. At 350 mA or above it will take a bit of time to see again. 

thus the best way is still, if You and Your caving buddies could test some lights inside a cave, possibly with different power levels.
What if You do all the work, finish the 1st light and then noone likes the more focused beam? Or the other colored light?


PS: I do understand that You dont want to switch to less light than now 
but how is it possible to compare "100 Lumen" at the Aceto with "100 Lumen" of a Led? 
1st light has no real beam, the other one lives just from its 8 deg. main beam.

PPS: what kind of lights do You guys use now when You have to reach out far into the dark?
Because I know no "normal" commercial headlamp that is good in this dept.


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## Tobias Bossert

yellow said:


> - for the "walk around use" the 350 mA for the headlamp is very bright,
> The mountain guide (which I asked to lead us because there were some 1st timers around) had his Aceto running and that 5 meter 360 degrees area light was just great. Dont think anything can make a similar nice light.



o.k., now we are near by...
Most of us use Petzl Aceto with 21l/h burner. You are right, this is a nice ligth, you can walk without needing to decline your head always downwards. It's known, the light output of Aceto is about 80 to 120lm. So it is realistically to achieve the same all-round light electrically. This is the task of my "work light". Indeed, I think we can make a similar nice LED light too!
Fist tests with different LED headlamps on the market were negative, they cut the beam too narrow! There is one exeption of a verry good commercial headlamp, www.scurion.ch but much to expensive for us. They also use a separate bare LED without any optics as work light and provide additionally a second LED with a narrow beam optics too.



yellow said:


> for distance work it was useless (You know that already)
> - for looking at larger distances (better a handheld lamp application?), even my Cree @ 1 A seemed too dim (this summer while visiting the Frauenmauerhöhle), but it was by far the strongest light of the group.
> PPS: what kind of lights do You guys use now when You have to reach out far into the dark? Because I know no "normal" commercial headlamp that is good in this dept.



Yes, this is the reason for the second LED with narrow beam optics. The LL3 from http://www.gaggione.it has a beam factor of 30 to 80 cd per lm, depending upon type of emitter. With a SSC P4 U luminance or a Cree XRE 7090 Q5 you will get about 5000 to 10000 cd (5 to 10 million mcd!) @ 700mA.
At the moment, most of us use commercial halogen headlamps from Petzl for this, but far less strong. I use a self made 10W halogen headlamp with really narrow beam (you see it on my personal photo). The combination LL3 plus LED @ 700mA is still brighter...



yellow said:


> There is also some other thing that can be annoying, especially with Led-headlamps (compared to the Acetos): being more focused, one tends to blind the person to talk to. At 350 mA or above it will take a bit of time to see again.



That's correct, the acetylene flame is much bigger than the dimension of the emitting area of a bare LED! This is indeed a disadvantage of using a bare emitter. I was thinking about using an optics with diffuser (very wide beam) this would solve this problem, but will cost some 15% of light at least!
The best way out is yust not found jet...



yellow said:


> but how is it possible to compare "100 Lumen" at the Aceto with "100 Lumen" of a Led?1st light has no real beam, the other one lives just from its 8 deg. main beam.



You can: The luminous flux of azetylene flames are known (in our case roughly about 100lm). The spatial pattern is nearly uniform. Color temperature is 2320K. So its possible to compare this directly with a bare SSC P4 with 3000K, also having a nearly uniform pattern. Our subjective tests with a selfmade testdevice in a cave some days ago showed, both light sources are comparable with one another!
Naturally you can't compare subjectively a uniform with a narrow beam light.

Now I also can provide you with first results of our color tests I anounced before.
In the past I was convinced of loam and limeston in caves being beige or even reddish brown. That's still true, but not to that extend! This was rather an artefact of the reddish carbide lamps we used in caves. The tests showed, that warm white brings no real improvement over natual white and even onle a small one over pure white, at least for pure white with temperature below 6000K!
But I will repeat this test again with the new Cree XRE 7090 5C Q2 (~4000K) and 87lm @350mA instead of 54lm.

Next I will make a testdevice with different spatial pattern for work light. Bare SSC P4 is quite uniform but bare Cree XRE 7090 has a somewhat smaler pattern. This testdevice also will cover combinations of bare emitters and wide beams too. I will post results when available...

At the end you will see: I do not make me problems which are still solved, as you posted earlier. I think there was nobody before, having solved these problems accurately before starting his design for a new headlamp, isn't it?

Best regard
Tobias


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## uk_caver

Having compared a Seoul running at a little under a Watt with a few carbide lights, it does certainly seem to be in the same ballpark, though it can't compete with a carbide in 'turbo mode'.

A wide beam is certainly useful underground, and there is the _group_ aspect of carbide users lighting up the cave all around them for other people to look at.

However, when it comes to my light lighting up things for me to look at, from experience first with a 'naked' LED with a near 180 degree spread beam, and secondly with a more restricted spread beam, roughly in a 90 degree cone, I barely notice the loss of the extreme wide light, but I definitely appreciate the increase in light within the more limited area, and that seems to be a widely-shared opinion among people I know who've tried both options.

Though I might be able to use some extreme-wide light in my peripheral vision, with an unmoving head I only have about a 60 degrees sideways range of stereoscopic vision, and a vertical range of about 90 degrees. A 90 degree cone tilted slightly downwards lights up almost anything I need to look at


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## yellow

last post in here, just to give an idea for testing ...



> However, when it comes to my light lighting up things for me to look at, from experience first with a 'naked' LED with a near 180 degree spread beam, and secondly with a more restricted spread beam, roughly in a 90 degree cone, I barely notice the loss of the extreme wide light, but I definitely appreciate the increase in light within the more limited area, and that seems to be a widely-shared opinion among people I know who've tried both options.


I would go even further and say that a led, especially a Seoul of Lux, is totally useless without focusing device. 
Maybe that so-said tighter beam degree of a Cree, but ... 
and
that 180 deg. led without focusing device disturbs Your opposite very much.
--> as is commonly known, the smaller the light souce, the higher the glare (right word?).
I'm just playing around with such a bare led (Seoul) and its totally annoying from anywhere I look at it. 

btw: I tested it with an *Elly*, modded with a Seoul and head removed
*and this light is why I do this post *
(as I do have the feeling You are not totally sure on what led, what focusing device and what degree to use. And without these, all the rest gives bad results, even when housing or circuits are an irreal 120 % effective).






PS: the 1st beam pic is with the head screwn out a bit, the full wide beam would be even more

When modded with the Seoul, the position of the led inside the Elly changes a bit.
* When the head is screwn in fully, the Seoul is too deep inside the reflector and this leads to a very broad main beam - perfect for checking what I have here in the room, just a few meters away (= area light).
* When screwn out a bit, its totally focused - much brighter but also very small hotspot
* Head removed - totally useless area light that not even shows the pieces 2-3 meters away that are good to look at with the wide beam 
and makes me look away, no matter from where I look at the bare led. 

The other plus of this very cheap, very easy to mod Elly is, that one could remove the reflector inside very easy and insert just any optic/reflector, screw in the head and the front glass pushes against that part and holds it in place.
That way, with getting a few different Led and different degree focusing devices, one can bring a light source along very easy and for cheap, to decide what is best and then use this in the real light.

Heck, they are so cheap, one could even get a few and mod them differentially - not to have to change the delicate parts


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## Tobias Bossert

uk_caver said:


> However, when it comes to my light lighting up things for me to look at, from experience first with a 'naked' LED with a near 180 degree spread beam, and secondly with a more restricted spread beam, roughly in a 90 degree cone, I barely notice the loss of the extreme wide light, but I definitely appreciate the increase in light within the more limited area, and that seems to be a widely-shared opinion among people I know who've tried both options.
> Though I might be able to use some extreme-wide light in my peripheral vision, with an unmoving head I only have about a 60 degrees sideways range of stereoscopic vision, and a vertical range of about 90 degrees. A 90 degree cone tilted slightly downwards lights up almost anything I need to look at



Thanks for your information. I got a similar feedback from some cavers in our club. My personal experience is, that it is more comfortable when standing still and looking into a room to have concentrated the light into a cone of about 60 to 90 degrees. All the other light around it is nearely not of interest, because you realize things only in this range. Say: the spill around this cone seems to be lost energy. 
But when you are walking over a rough surface, e.g. bolder stones, you need the spill touching your feet (or you have to incline your head up and down frequently to gather the information), otherwise you might stumble . It's interesting, you don't become aware of the things around your feet intentionally but nevertheless you need it.
May be, we should look for a non concentrical beam pattern...
I will put this problem on the back burner at the moment and call up again when finished the studies on required luminance in caves depending upon color temperature.


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## Tobias Bossert

yellow said:


> 180 deg. led without focusing device disturbs Your opposite very much.



You are right, that's why I posted my thoughts on using LED with optics and diffuser instead of bare emitter earlier: This increases the light emitting area tremendously. But it costs efficiency too...

Thanks for the pictures of this versatile mod of Elly! But I have build my own test device with 10 switchable places for emitters/optics, so I'm able to test 10 different configurations at one cave trip.



yellow said:


> as I do have the feeling You are not totally sure on what led, what focusing device and what degree to use. And without these, all the rest gives bad results, even when housing or circuits are an irreal 120 % effective



Yes, you are absolutly right! At the moment I do not know which LED and what kind of focussing device to use for working light. That's the reason why I make all these tests and experiments: finding out what I need!
And that is one of the reasons why I posted this treat: To learn from everyones experience...


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## uk_caver

Tobias Bossert said:


> But when you are walking over a rough surface, e.g. bolder stones, you need the spill touching your feet (or you have to incline your head up and down frequently to gather the information), otherwise you might stumble . It's interesting, you don't become aware of the things around your feet intentionally but nevertheless you need it.


I'd guess that for normal walking, my eyes would be zoned on a point maybe 5 or 6 metres in front of me, with my head tilted accordingly.
Additionally, I mount my light in a mining lamp headset, which (in conjunction with the helmet bracket) ends up with the lamp axis being tilted somewhat downwards relative to 'helmet horizontal' or 'head horizontal'.
Finally, I don't usually need to look directly down, I only really need to see the place where my next steps are going to be, and that's a little way in front of me.
The end result of those three factors is that a 90 degree (full-angle) cone seems to work OK most of the time without needing any obvious extra head-tilting.

However, the other LED in my setup can also provide quite significant downlighting when it's on, and with uneven floors I'd tend to have that LED running at least at low power, since it's the one that provides distance lighting for route-spotting, so it's possible that there are times when my cone of wide light isn't quite wide enough on it's own that I don't notice.


----------



## yellow

> build my own test device with 10 switchable places for emitters/optics, so I'm able to test 10 different configurations at one cave trip.


wow, 
I bet You plan to make more than just one lamp - quite some efforts ...


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## 5kids

Have you considered trying an Princeton Tec apex and replace the LED with a warmer emitter? The apex is rated to 1M water depth. They now have an exteme version with a remote battery 8AA pack, or you could use our own battery pack with any of the apex varients. The apex mod is easy and you can pick your tint of emitter to use. I love my modded apex.

BTW, Princeton Tec has no info on the website regarding the apex extreme.

http://www.brightguy.com/products/Princeton_Tec_APEX_Extreme.php


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## Tobias Bossert

yellow said:


> wow,
> I bet You plan to make more than just one lamp - quite some efforts ...



Yes, this is right, we plan to build our own headlamps for some members of our caving club. 
***We definitly do not plan to sell those lamps*** 
Quite the other way round: Any results - failure as well as found optimization - will be posted here. So we hope that some manufacturers will take some ideas from this discussion and develop a new headlamp or optimize an existing model. This would be very helpfull for us and othes too, because everyone can avoid building final lamps by hand!

But up to now, I know only one really good commercial headlamp for caving (www.scurion.ch) - much too expensive! And even this one could be further improved with respect to color temperature and pattern of its bare emitter working light.
There is no option at the moment to choose one model on the market and modify it with actual highly efficient LEDs.

Last but not least: you should calculate neither the time spent to experiment with this things nor the money you spent to build your test-devices and pre-models, it's just our hobby! The efforts you mentioned, that is what enyoys!


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## uk_caver

Tobias Bossert said:


> But up to now, I know only one really good commercial headlamp for caving (www.scurion.ch) - much too expensive! And even this one could be further improved with respect to color temperature and pattern of its bare emitter working light.


I guess it depends what you mean by 'improve'.

White LEDs can seem cold, but yellower ones aren't necessarily much better. In the days when I made luxeon-powered lights, and the LEDs I got weren't sold by colour bin, about half were 'proper' white, 30% yellowish, with the rest a little blue (apart from a couple with a purple tint).
Going straight from using carbide, the yellowish ones maybe seemed a bit less cold than the white ones, but didn't seem quite as good for actually lighting things up, or for colour accuracy.
Maybe for a wide beam, a red or amber LED could be added to the mix to give a more carbide-like light, but I'm not sure many people I know would go for that if it meant extra power consumption/loss of efficiency. It'd also be trickier to match in a focussed beam.
Equally, though there can be initial comments when switching to a 'colder' light, that does seem largely to be a matter of adjustment.
Commercially, tint doesn't seem to be much of a selling point, and I'd guess that minor complaints would generally be about something being too off-white in any direction (blue, yellow, red, or green).

Also, 'improving' a wide beam is still a matter of taste. Though I'm happy with what I do regarding narrowing a wide beam somewhat, there are certainly people around here who really want a complete 180 degree spread.
I haven't had any complaints about my approach, but given it was completely free and easily reversible, there wouldn't be much to complain about, and having 2-3x better forwards throw compared to a naked LED gave it a definite advantage.


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## Bandgap

Hi Tobias

From my very limited caving experience, I would say arrangement D is the best option as it can be difficult to get your hands to your chest to operate light controls. And the controls would have to stand regular scraping along the ground without adjusting. 
You will have fun squeezing the electronics into that small space. 

I have been debating battery technology for caves. 
Lithium ion seems ideal, except that the contents are inflammable and in amazingly rare circumstances they have been know to burst into flames - from over-charging - not a problem for you - over heating or physical blows, crushing or piercing. 

So A nice strong box with not too much thermal insulation if you are running them hard. 

Also, a question - what cable are you thinking of using and how would you attach the cable at both ends as these seem to snag on rocks ad get pulled hard. 

As for colour rendering - whatever the apparent colour temperature, 'white' leds have very little green and almost no red in their spectrum, so colour rendering is poor compared with a well-driven halogen lamp. 
I suspect, being incandescent, a carbide lamp had plenty of red and also most of the spectrum - at least as far as blue. 

And - my preference and I know some people here disagree strongly - I favour adjustable light output - either by continuous control or in small steps - or at least three level including an I-am-only-eating-my-sandwiches-and-don't-want-to-blind-everyone setting. 

Happy caving

Steve


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## uk_caver

Bandgap said:


> As for colour rendering - whatever the apparent colour temperature, 'white' leds have very little green and almost no red in their spectrum, so colour rendering is poor compared with a well-driven halogen lamp.
> I suspect, being incandescent, a carbide lamp had plenty of red and also most of the spectrum - at least as far as blue.
> 
> And - my preference and I know some people here disagree strongly - I favour adjustable light output - either by continuous control or in small steps - or at least three level including an I-am-only-eating-my-sandwiches-and-don't-want-to-blind-everyone setting.
> Steve


I can't say I've noticed a colour rendition problem with LEDs when caving, whether illuminating rock or other cavers. Even side-by-side with halogen or carbide, the only obvious difference seems to be in terms of colour temperature, not rendition. I guess there just aren't enough things underground where green is important.
The place where there does seem to be a difference is on the surface, illuminating grass, etc.

I like having multiple powers, but after playing around, for practical purposes I reckon power steps of less than a factor of 2 or 3 are probably too close to be useful.


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## Bandgap

uk_caver said:


> I can't say I've noticed a colour rendition problem with LEDs when caving, whether illuminating rock or other cavers.....
> 
> I like having multiple powers, but after playing around, for practical purposes I reckon power steps of less than a factor of 2 or 3 are probably too close to be useful.



Just thought I would point out the colour thing in case there are purists wanting to enjoy strata to the full. I suppose limestone is pretty dull wherever you find it. 

As for the steps, I think steps of 2x or 3x brightness are pretty good- as the eye takes the log (or whatever) of this and makes it apparent steps of 1.4 to 1.7 (ish).
But they do need to go down far enough IMHO. 

Apart from the cable, my biggest quastion was how to make a switch or control robust enough while keeping it small. 

Steve


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## TorchBoy

Bandgap said:


> As for colour rendering - whatever the apparent colour temperature, 'white' leds have very little green and almost no red in their spectrum, so colour rendering is poor compared with a well-driven halogen lamp.


Perhaps you're thinking of _blue_ leds?


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## uk_caver

Bandgap said:


> Just thought I would point out the colour thing in case there are purists wanting to enjoy strata to the full. I suppose limestone is pretty dull wherever you find it.


I'm not sure about _dull_, but most of the stuff I've seen underground tends to be somewhere between white, black and brown.
However, to me, the various kinds of red caving gear still look essentilly the same red under white LED lighting as under daylight, so there's enough red light to allow the brain to construct the impression of a full spectrum.
I don't need any more red than that, though I can understand some mine explorers looking at subtly different minerals might have a different view.


Bandgap said:


> Apart from the cable, my biggest question was how to make a switch or control robust enough while keeping it small.


I guess a lot comes down to the casing. If you're making your own housing and trying to avoid possible water ingress points, it's certainly possible to do something with internal reed switches/external magnets. With a cylindrical housing, making an external rotating ring with a magnet in, (as some people do with torches) is probably not too hardto at least get working, though making one that looks good may be rather harder (assuming there isn't some _objet trouve _lying around that does the business).


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## 2xTrinity

uk_caver said:


> I guess it depends what you mean by 'improve'.
> 
> White LEDs can seem cold, but yellower ones aren't necessarily much better. In the days when I made luxeon-powered lights, and the LEDs I got weren't sold by colour bin, about half were 'proper' white, 30% yellowish, with the rest a little blue (apart from a couple with a purple tint).
> Going straight from using carbide, the yellowish ones maybe seemed a bit less cold than the white ones, but didn't seem quite as good for actually lighting things up, or for colour accuracy.


I think the old luxeons that were essentially cold white LEDs that ended up being "yellowish" by chance were not the same as current-generation warm white Cree LEDs, which appear closer to blackbody and less "greenish" than bin outliers that just happen to be warmer.



> Equally, though there can be initial comments when switching to a 'colder' light, that does seem largely to be a matter of adjustment.


I believe different color temps suit different applications. For example, or trying to do intensive shop/design work, I like 5000k. For "ambient" light, I like 3000k. In most other cases, I prefer a compromise of ~3500k. I generally don't like to stray outside the range of 3000k-5000k.



> Also, 'improving' a wide beam is still a matter of taste. Though I'm happy with what I do regarding narrowing a wide beam somewhat, there are certainly people around here who really want a complete 180 degree spread.


If you want a 180% spread, do your buddies a favor and use a diffuser over the LEDs -- this will help with glare immensely. You can buy lenses from Flashlightlens.com with diffusion film and AR-coatings already installed. I'd recommend a shallow reflector, with a diffuser. This will produce a flood light that still has slightly more intensity in the center of the field of vision (similar to what you'd probably get with a "clean" carbide lamp).



> As for colour rendering - whatever the apparent colour temperature, 'white' leds have very little green and almost no red in their spectrum, so colour rendering is poor compared with a well-driven halogen lamp.


Most current-generation white LEDs emit the majority of their power in what would be considered the "green" portion of the spectrum -- that is where the high lumens ratings come from (green is where the eyes are most sensitive).The reason older LEDs were much more bluish was that phosphor depositing process was less efficient and would impede light extraction too much, so thinner layers were most efficient. That's improving though -- the fact we have Warm Cree LEDs at Q2 efficiency is evidence of that.

The problem with color rendition is essentially the same as old single-phosphor fluorescents used to have -- the "red" output is actually more like orange, which is enough to counterbalance the blue and make the overall packaging look white, but provides little contrast when distinguishing shades of red/brown. A potential solution to that is to actually use multiple phosphors with the LEDs, just like modern multi-phosphor fluorescents.



> Maybe for a wide beam, a red or amber LED could be added to the mix to give a more carbide-like light, but I'm not sure many people I know would go for that if it meant extra power consumption/loss of efficiency. It'd also be trickier to match in a focussed beam.


There isn't much advantage to adding amber -- the only real deficiency is deep red wavelengths. Adding a true red (rather than amber or red-orange) to an array of white LEDs, particuarly ones with a "greenish" off-white tint does produce some very good results. Efficiency loss is neglibile, a surprisingly small amount of red is needed to "fill in the gaps" in the spectrum. 

The problem though is with color mixing/packaging. An actual Emitter package that included a red die INSIDE the package would be pretty interesting, but probably not worth the trouble compared to a second phosphor.


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## 2xTrinity

uk_caver said:


> I guess it depends what you mean by 'improve'.
> 
> White LEDs can seem cold, but yellower ones aren't necessarily much better. In the days when I made luxeon-powered lights, and the LEDs I got weren't sold by colour bin, about half were 'proper' white, 30% yellowish, with the rest a little blue (apart from a couple with a purple tint).
> Going straight from using carbide, the yellowish ones maybe seemed a bit less cold than the white ones, but didn't seem quite as good for actually lighting things up, or for colour accuracy.


I think the old luxeons that were essentially cold white LEDs that ended up being "yellowish" by chance were not the same as current-generation warm white Cree LEDs, which appear closer to blackbody and less "greenish" than bin outliers that just happen to be warmer.



> Equally, though there can be initial comments when switching to a 'colder' light, that does seem largely to be a matter of adjustment.


I believe different color temps suit different applications. For example, or trying to do intensive shop/design work, I like 5000k. For "ambient" light, I like 3000k. In most other cases, I prefer a compromise of ~3500k. I generally don't like to stray outside the range of 3000k-5000k.




> Commercially, tint doesn't seem to be much of a selling point, and I'd guess that minor complaints would generally be about something being too off-white in any direction (blue, yellow, red, or green).


I believe a lot of the earlier "warm white" LEDs were essentially off-white toward yellow-green, as they still had too little red. Modern warm emitters, like the Cree Q2 linked earlier, are reputed to be muhc stronger in red -- so that it appears white -- but still not as good as a halogen in that respect.



> Also, 'improving' a wide beam is still a matter of taste. Though I'm happy with what I do regarding narrowing a wide beam somewhat, there are certainly people around here who really want a complete 180 degree spread.


If you want a 180% spread, do your buddies a favor and use a diffuser over the LEDs -- this will help with glare immensely. You can buy lenses from Flashlightlens.com with diffusion film and AR-coatings already installed. I'd recommend a shallow reflector, with a diffuser. This will produce a flood light that still has slightyly more intensity in the center of the field of vision (similar to what you'd probably get with a "clean" carbide lamp).



> As for colour rendering - whatever the apparent colour temperature, 'white' leds have very little green and almost no red in their spectrum, so colour rendering is poor compared with a well-driven halogen lamp.


From LED Museum, Spectrum of Cool White Cree LED:





LEDs have no deficiency in green -- most current-generation actually emit the majority of their radiant output in the yellow/green region of the spectrum. The problem is same as old single-phosphor fluorescent used to have -- the "red" output is actually more like orange, which does make the overall packaging look white, but provides littel contrast when distinguishing say shades of brown. The best engineering solution to that would be to actually use multiple phosphors with the LEDs, just like modern multi-phosphor fluorescents.



> Maybe for a wide beam, a red or amber LED could be added to the mix to give a more carbide-like light, but I'm not sure many people I know would go for that if it meant extra power consumption/loss of efficiency. It'd also be trickier to match in a focussed beam.


There isn't much advantage to adding amber -- the only real deficiency is deep red wavelengths. Adding a true red (rather than amber or red-orange) to an array of white LEDs, particuarly ones with a "greenish" off-white tint does produce some very good results. Efficiency loss is neglibile, a surprisingly small amount of red is needed to "fill in the gaps" in the spectrum nicely. I believe some of the warm white LEDs in the past have included multiple phosphors to achieve the same effect, and i expect more to in the future as LEDs are pushed for general lighting.


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## uk_caver

2xTrinity said:


> I think the old luxeons that were essentially cold white LEDs that ended up being "yellowish" by chance were not the same as current-generation warm white Cree LEDs, which appear closer to blackbody and less "greenish" than bin outliers that just happen to be warmer.


I'm sure the colour was more accidental, though of all the Lux Is/IIIs I used, I don't recall any looking noticeably green.
A friend's commercial LuxIII-powered light does have a definite green cast, and though I guess the eye would adapt to it, when there are cleaner white lamps around, it does look rather nasty.



2xTrinity said:


> There isn't much advantage to adding amber -- the only real deficiency is deep red wavelengths. Adding a true red (rather than amber or red-orange) to an array of white LEDs, particuarly ones with a "greenish" off-white tint does produce some very good results. Efficiency loss is neglibile, a surprisingly small amount of red is needed to "fill in the gaps" in the spectrum.


Amber might give the carbide feel some people have fond memories of. I'm not sure how many people with carbide nostalgia are really too concerned about colour rendition.


2xTrinity said:


> The problem though is with color mixing/packaging. An actual Emitter package that included a red die INSIDE the package would be pretty interesting, but probably not worth the trouble compared to a second phosphor.


I guess a twin die brings up the problem of sharing power in proportion (or having twin drivers), whereas an extra-phosphor approach does balancing automatically. Maybe when use for indoor lighting takes off, multiphosphor white LEDS would find a ready market.
Still, for a personal _experimental_ light, reddening a wide beam with an extra LED is certainly possible, given enough space in the headset.


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## Beaker

Hi Tobias, I'm quite surprised that no one has mentioned the Stenlight S7 in this thread (http://www.stenlight.com/) -- it's a purpose-built caving lamp that is rapidly growing in popularity among USA cavers. I don't own one but many of my caving friends do, and it's really an impressive piece of work in terms of construction, light output, and efficiency. It's not cheap -- a basic setup of light + custom Lithium-Ion battery sells for about US$300 or so -- but all the cavers I know who have them have been extraordinarily pleased with them.

There are discussions about it both on this board and at cavechat.org (the US NSS discussion board), eg 

http://www.forums.caves.org/viewtopic.php?p=296&sid=85eec0fe766dd5347106387cb3516203

If you are looking for a caving-specific LED headlamp, I'd highly recommend you check out the Stenlight if possible. (I'm assuming it's available in Europe...)


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## uk_caver

Doesn't the Stenlight run both LEDs in series?
If so, it's not great for people looking for a smooth (non-spot) beam unless they lose the optics on both LEDs and then get another light for spot use.


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## Tobias Bossert

Beaker said:


> If you are looking for a caving-specific LED headlamp, I'd highly recommend you check out the Stenlight if possible. (I'm assuming it's available in Europe...)



Yes, I read the thread upon Stenlight headlamp and I looked at the page of the manufacturer. It seams to be a good and robust headlamp indeed. But it still doesn't comply with our requirements as I posted in the beginning of my thread.
There are two LEDs in series, always used together. Each using its own optics. Consequently the only possibility to change the spacial pattern under use would be to attach and remove an additional diffuser, not very handsome in caves...
The beam is a compromice between throw and flood: It neither meets one of both requrements. We need flood working light all over the day and for short term usage only super narrow beam (without spill).
On the other hand it provides 70 lumens output for 3 to 5 hours only (consuming 4 to 5W, not quite good nowadays). So you will need 2 or 3 battery packs (up to 6 pieces of 18650 cells) per day...

There is indeed a much more suitable headlamp on the market, www.scurion.ch, but I would like to surpass it technically and nevertheless avoid its high price (about $ 500).


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## uk_caver

Leaving aside the underground practicalities, how easy would it be to fully diffuse a spot beam without losing a deal of light in the process?
Wouldn't a diffuser tend to cause backscatter?


----------



## Tobias Bossert

After some month of experimenting I come back to this treat. We tested all kinds of optics – now I can demonstrate some reasonable solutions.

*1) Normal light for walking and climbing*

Neither TIR with narrow, medium or wide beam nor plain LED satisfied our requirements. On the one hand all TIR are not wide enough for walking (you tent to stumble) but on the other hand, plain LED without any optics is to fade (you can’t see where to go).
We tested many combinations of two simultaneous LED and find one combination satisfying us in real cave tests: Combination of a medium beam with FWHM of about 16° and a very wide beam with FWHM of about 80°.
I realized this with XR-E Q5 using Carclo ripple medium (10210 & 10205) and with SSC P4 U using Carclo wide angle reflector (10170 & 10363). The axis of the medium optics is horizontal (when you stand upright) and the wide reflector is declined downwards 20 to 30°, as shown in Figure 1.





This free mounting without case was for photo documentation only.

It is not easy to demonstrate the feeling of the combined beam in a picture. I put the LEDs 50cm apart from a vertical white wall while the photo was taken from about 150cm from the wall – otherwise I would need a fisheye photo lens losing the orientation. The medium beam is horizontal and the pattern therefore is circular. The wide beam is declined downwards and therefore projects elliptical; it just reaches the area immediately in front of your feet. In reality you will not realize the sharp boundary of the beam, this is due to the photo taken from thee times the distance from the wall.






Both LED were driven by different current levels. The XR-E Q5 for the medium beam needs about 30% of the current of SSC P4 U in the wide angle reflector to achieve the impression of the figure above. We plan to provide two levels: 40m + 130mA and 90 + 300mA, so we can hold this level for about 24 or 10h with 6 alkaline AA.

*2) Pause light*

We plan to use the above mentioned medium beam with a current level of about 20mA.

*3) Spot to explore deep pits or high shafts*

At the beginning I was sure we should use Gaggione Mobdar or Gaggione LL3 because so many users mentioned them positive. But these TIR are relatively big and provide a lot of side spill too. There exist completely different TIR (‘catadioptric reflector optics’ using total reflection on the front plain and being metalized on the backside, e.g. Carclo 10144) with extremely narrow beam, but these beams are too narrow for us (at the ground of a deep pit you will see one big stone only instead of the floor of the pit completely). We tested almost all TIR and reflectors from Kaidomain and Dealextreme and others and found nothing satisfactory.
Cree XR-E has its own internal optics narrowing the beam a little bit, so it is possible to gather almost all of its flux with a thick aspheric collimator lens. We also tested almost all acrylic lenses we found. One very cheep lens with 23mm diameter was suitable and performs quite good. This lens is sold with different holders (DX 4614, DX 4628) which do not fit for XR-E. Therefore we cut the bottom of the holder away and inserted a Carclo holder for Cree (10205). With this combination you can adjust the lens. Both holders form something like a telescope.






This device is much smaller than Mobdar or LL3 as you can see in the following picture.






The combination of the two holders allows adjustin the beam. The beam is narrowest when the lens forms an image of the die on the wall: 






The rectangular shape of the die is about 40x40cm at a distance of 5m. As you approach the LED to the lens, the beam gets broader, round but weaker too; the left beam is about 150cm in diameter at 5m.






I also compared the single lens with Mobdar. The beam of the lens is set to about 70cm at 5m (rounded but not jet round). The peak intensity of illumination in the center of the beam of Mobdar is about 70% of this, but it seams that the overall flux of the Mobdar is higher and the beam is much more “beautiful”. On the other hand the beam of the lens is “without” spill, that’s what we need.

We plan to use the single aspheric lens with XR-E Q5 at about 1A. This is for short term use only. It works fine with 6 fresh alkaline AA, but when they got discharged they will limit the current rather than the regulator. With NiMH AA cells this is no matter.

*4) As much light as possible for big halls*

We tested the SSC P7 for this. We found no compact TIR (< 30mm). Since P7 has no internal lens the original beam is too wide to gather all flux with an aspheric collimator lens. Smooth reflectors throw donuts or beams with a dark cross in the center. So you must use orange peel reflectors. But – as I know now – orange is not orange. The roughness should be high enough with respect to the focal length. Most OP reflectors I found at Kaidomain and Dealextreme were not rough enough. Only two of the smaller types can be used with P7 avoiding severe donut effects: 
DX 5951 (similar to KD 3317) has diameter of 18mm only. The hole for the emitter must be opened to fit over the dome of P7 (9mm). This gives a relatively wide beam with only a week donut.
DX 3257 has diameter of 26,5mm. You must cut the holder side so that surface on the backside of the hole for the emitter is plain. Additionally you must open the hole to fit over the dome of P7. This gives a medium beam with a week donut.
If you don’t like this week donut, use a diffuser from L2Optics or Polymere. But this will cost at least 15% of the flux! If we could find a stronger orange peeled reflector, the donut should be avoidable without diffuser. I just ordered KD 5405 (23mm), KD 3318 (24mm) and KD 5151 (25mm) to try these too. For the moment I prefer the DX 3257. You can see the beam of modified DX 3257 with P7 in the picture below.






We plan to drive this P7 with about 3A. This is for short term use only. It works fine with 6 NiMH AA cells, but with alkaline AA the current will be limited to their strength naturally.

*5) Put all together*

At the moment we plan to build a headlamp with 4 LEDs and optics as described above. This should get not to big for a caving helmet, as you can see on the following picture:






But what is about the housing? 
No idea at the moment – I still hope that some manufacturer takes my ideas and starts its own development on that base.
But at the moment, there is no such manufacturer. Therefore I have to continue...
For this I assembled the circuitry for such a headlamp using cheep drivers from far east:






Next I will construct a prototype and lend out to my caving friends to optimize it. This will consume some time...

 P.S.: Moderator please help! 
The links to my pictures work well, but I can't insert images. After saving changes, they were gone. Why? Please, can anyone tell me what I'm doing wrong:
I push the button 'insert image' than the window for the URL appears with default 'http://'. When I overwrite it by the link and accept, than the text window shows an icon at the place of insertion. After 'save changes' no pictures appear but all icons are gone too...
*P.S.: Problem solved now:
I used Firefox 2.0.0.16 with add-in Control de Scripts 1.03 and add-in AVG Save Search 8.0, which do not insert images correctly. With older versions of Firefox or with MS IE there is no such problem.*


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## Yucca Patrol

Tobias,

I applaud your effort and thoroughness. As a fellow caver, I am always searching for the ultimate caving headlamp and will look forward to seeing what you end up with. :twothumbs


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## uk_caver

A four-LED light? That does seem a fairly serious project.

Might it not be easier as a general 2-led caving light, and a more 'specialist' room-lighting and shaft-spotting light?

I imagine there might be some kind of market for a specialist light among the large numbers of people who already have some other kind of caving light that they're happy with (Duo LED, etc)
Possibly a specialist light would be better as a handheld unit, since for shaft-examining (at least when looking upwards), a helmet mounted spot beam can literally be a pain in the neck.
When I was playing with some P7s, the main use I found for a very bright flood beam was for photography, which is also a use where a lamp is more useful in the hand than on the helmet.

Also for the P7 room-light, have you tried using a conical reflector? If you don't want any kind of _beam_, just a rather more forward-biased light than you get from a naked LED, it's definitely worth trying.

With your FWHM of 80° using reflectors - looking at the datasheet, a naked Cree has a FWHM of only about 90°.
How different is the reflectored Seoul to a naked Cree?
Is it just a case of the Seoul+reflector eliminating 'wasted' extreme-wide light?


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## Tobias Bossert

uk_caver said:


> A four-LED light? ...
> Might it not be easier as a general 2-led caving light, and a more 'specialist' room-lighting and shaft-spotting light? ...
> Possibly a specialist light would be better as a handheld unit, since for shaft-examining (at least when looking upwards), a helmet mounted spot beam can literally be a pain in the neck.



Yes, uk_caver, I know this discussions. There are pros and cons. About 20 years ago I constructed my first handheld halogene thrower (10W 6V in the housing of flashlight for 'flat battery' 4,5 V with 6 NiCD AA). Works very well at that time. Good when standing at the floor of a high shaft in the ceiling, because there is no problem taking it out of your baggage ant it is good for your neck. But bad in case you are descending a rope into a pit. On my personal icon you can see me with carbide lamp plus halogene thrower on my helmet (constructed 1995).
Since the additional space and weight of the LED optics are very small, I decided to integrate all three lamps (working light with 2 LED, thrower with 1 LED and flooder with 1 LED) into the headlamp.



uk_caver said:


> Also for the P7 room-light, have you tried using a conical reflector? If you don't want any kind of beam, just a rather more forward-biased light than you get from a naked LED, it's definitely worth trying.



Yes, I tried P7 with conical smooth reflector Carclo 10170. The beam is not homogeneous. I will look for some orange peeled alumine to try it for my own. But at the moment I have no source for alumine sheet with high orange peeling.



uk_caver said:


> With your FWHM of 80° using reflectors - looking at the datasheet, a naked Cree has a FWHM of only about 90°.
> How different is the reflectored Seoul to a naked Cree? Is it just a case of the Seoul+reflector eliminating 'wasted' extreme-wide light?



There are some differences.
1) XR-E has its maximum on axis and decreases the intensity continuously apart from it; at about 45° off axis intensity is half maximum. If you combine this with a narrow beam 30° off axis, than you get two maxima in the vertical. SSC P4 with Carclo 10170/10363 gives an flat intensity over almost 80° and than drops fast. If you combine this with a narrow beam 30° off axis, than you get one maximum only in the vertical.
2) XR-E has reasonable spill outside of its 90° beam. This may dazzle your friends when talking with them. With SSC P4 and reflector you just have to decline your head about 10 to 15° and the eyes of your friends are out of beam.

But the problem of dazzling is still unsolved. I experimented wit diffusors of Cree (L2-Optics) and Polymere, but are not happy with it. Both work well to soften and broaden a narrow beam (reducing the overall flux about 15%). But used with a extremely wide beam, the losses ar much higher and increase with off axis angle. This could be solved only by spherical or domed diffusors, but I could not find such devices on the market.

Regards Tobias


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## uk_caver

I do see that the ideal close-up 'spot' beam is probably something like your 16° beam, since it will light up a reasonably wide area close to the caver, but I guess that does mean that it loses enough performance at long distances that you need an extra tight spot beam.

I find that even with a tight reflectored spot with a _very_ sharp fall-off outside the beam, mixing a dim-to-medium spot with centre-biased flood seems to make the spot beam subjectively rather wider at short-to-medium distances (alternatively, the spot beam 'pulls out' the flood beam and makes it seem throwier even outside the spot).
I think it's down to objects outside the spot beam still being somewhat visible in the flood after the beam has passed over them - as long as they don't fall into relative blackness, they stay much better in the mind's attention.
This seems to work best with a lower power spot than flood beam, since there isn't as great a contrast at the edge of the spot. Too bright a tight spot can actually makes a light less usable close-up.


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## MiniLux

Tobias Bossert said:


> P.S.: Moderator please help!
> The links to my pictures work well, but I can't insert images. After saving changes, they were gone. Why? Please, can anyone tell me what I'm doing wrong:


 
You may simply use http://www.postimage.org/, it works very well for that purpose


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## Tobias Bossert

Hi uk_caver,
there are two beamshots to compare bare XR-E with SSC-P4 and Carclo 10170/10363







and






I have many holders and 5 reflectors 10170. 3 reflectors snap in easily having a very good flatness of the beam and being nearely circular. 1 needs little more force to snap in but still has an acceptable beam too. 1 needs strong force and shows a beam with some (weak) artefacts and a shape somewhat elliptical. This one is on the photo - worst case!

The beams are quite different. The emitter was 50cm apart from the wall with axis rectangular to the wall. The photo was taken from about 150cm with wide angle.

Regards Tobias


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## jirik_cz

Tobias Bossert said:


> This could be solved only by spherical or domed diffusors, but I could not find such devices on the market.



Check this http://www.khatod.com/pdf/pljt20_xlamp.pdf


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## outer limits

Hi Tobias,

Thanks for all the info, keep it up. I have been having a small play around but only to the extent of fitting leds into an existing mining light. I have been using a DX 1917 which I found easy to cave with and it did not seem to raise too many complaints from others in the party although I have been using elecrtic for a while so I am used to not looking directly at people. Liked the info on the modified drivers so might have to change.


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## degarb

Great thread. Worth reading a second time.

Daily, I do task work with headlamps. But found an essential missing puzzle piece is the wristlight. I've been building (left) wrist-lights since December. So far, best setup is an xr-c coleman 75 lumen two inch head hacksawed off, velcroed on to the power pack of 4 AA that is glued to elastic and velcro. I adjust to angle I need, as needed per task. 

The benefits of a wristlight over a headlamp alone are several: 1. when walking the wrist light is pointing and illuminating your feet, so peripheral vision can see stumbling issues. 2. you can flick a thrower about faster than you can whip your head about, to find things and spot danger. 3. more flood and field of vision than just head lamp. 4. law of inverse square means brighter walls gut level and below. 5. extra battery source. 6. backup if head lamp breaks. 7. much better textural relief vision, as a silloette shows shape of walls (I can spot baseboard dust from 25 foot.) 8. more diversity of light temperature and angle means more subtle understanding of what you are looking at 9. another 75 to 100 lumens at 1 watt, minus the obvious losses.

I settled on the $20 xr-c coleman over the floodier 3 aa xr-e(hack saw off head for aa conversion) since throw is awesome with better than lux1 corona. I use rheostat, where the xrc throws great at 200 milliamps or as low as an efficient 80 milliamps , but rocks at 400 milliamps to astonishing effect.


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## jirik_cz

Hello Tobias. This reflector for P7 might be interesting http://www.ledil.com/datasheets/DataSheet_Boom_p7.pdf


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## uk_caver

The two wider-angle devices seem to have definite patches from the 4 dies in the LED, even though the narrower-angle one doesn't.


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## gillestugan

Great work Tobias!
Thank you so much for showing how to wire multiple PT4105 in parallel using one switch for regulating output to all of them. 

My plan is to build a lamp for caving and general outdoor using two MC-Es. One very wide flood and one narrow.
I'm probably going to use 4 X PT4105 and the dies wired 2 in series with each pair individually driven.
This will give me a very wide input range of about 8-18V.

Regarding the housing:
I've used an aluminium box for a 3X XR-E setup which works very well. It handles the heat well, is waterproof (if o-ring or other seal is used) and is quite cheap. EUR 4.40. Just not as good looking as I wanted. I would prefer an oval housing. Anodised in gold, red or black. 
Here is the box: http://www.conrad.de/goto.php?artikel=522369

Regards /Gille


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## Tobias Bossert

Long pause, but work was going on... 
Now I completed my first test device: It's on a four days trip into a 95km-cave (Hierlatzhöhle) at the moment to get real life experiences with it.
My first test device is completely hand made - no usefull bases for professional manufacturing. 
The purpose is to demonstrate the feasibility of improved lightning with respect to commercial high end headlamps. The crew also uses some Scurions at the same expedition and one Stenlight.
The test device is build in a plastic case (ABS), the original lid is changed by a 3mm alumine back plate. The outside dimensions are width 85mm (plus switch knob), hight 56mm and depth 22mm (plus outstanding lower lens tube). The weight is 155g without mechanical helmet fixation and without cable, battery case and connector. With 1m cable (as used now to carry the battery in the chest pocket) and connector the weight of the headset is 195g.







The switch has 6 positions:
off
pause light (upper source in picture: XR-E Q5 WC & Carclo 20mm frosted narrow)
worklight low (= pause light + lower source in picture: XR-E Q5 WC & Carclo 20mm wide angle reflector & self edged glas lens; declined)
work light high (= work light low but higher currents)
shaftspot (left source in picture: XR-E Q5 WC & EdmundOptics lens AX77183)
hallflooter (right source in picture: P7 CSXO & modified DX 3257 & Ledil Cree 26mm diffuser 20° bond with epoxy onto a glas lens)
With 6 AA NiMH (2500 mAh) the runtimes are: 2. more than 250h, 3. about 25h, 4. about 8h. Positions 5. and 6. are for short term use only (drawing about 4w / 12W).

With respect to my former posts, some modifications took place:
I didn't found a reasonable small OP reflector for P7 not throwing a donut, therefore I use now a moderate diffuser. This would be even strong enough to use a SMO reflector (DX 5955) . The diffuser is acrylic - not usefull without a separate hardened cover. When I put a plane glas lens in front of it, the light passes 4 surfaces giving reflections. Therefore I bont the diffuser with its plane side to the glas lens using a clear epoxy. This improves the transmittance noticeably. As a side benefit it stabilizes the glas lens: if it breakes up, there is a crack, but the acrylic part still holds.
I got a big collection of lenses and reflectors at home now. The outstandingly best glas lens is AX77183 from EdmundOptics (AnchorOptics), which allows a very compact thrower. The lens has a usfull diameter of 19mm. The internal depth of my case (19mm) is sufficient for XR-E on a star board to throw a sharp image of the die to a wall. I mounted the lens by about 1mm nearer to the LED (with respect to the inner side of the housing) to smooth out the details of the die image. The picture shows the beam 2m apart from the case; FWHM is about 4,3°.​ 


 
The worklight gives a combined pattern. The upper source is a 20mm Carclo TIR, the centre is horizontal. The lower source is a 20mm Carclo wide angle reflector, originally designed for lambartian LED only. Slightly modified to XR-E the FWHM is about 65° only. I covered it by a glas lens, which I edged by myself. There are two beamshots of the worklight. The distance of the headlamp from the wall was 50cm, the center of the upper part is slightly higher than the middle of the folding rule (at 100cm).​ 


 


 
The four days cave trip ends December 30. If there is no defect, the test device will be used on the next four days cave trip on January 3.​ 
I will post the findings!
And naturally discuss the experiences an try to improve the device.​


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## Guy's Dropper

Wow! What a project. It's probably too late to mention this, but CR123A Primary batteries would be much better suited to caving than alkalines. They have a much higher energy density, are more reliable and work in more extreme temperatures than alkaline batteries. I'd say the weight you could save would definitely be worth the effort. If you are having a hard time finding them, order them in bulk online for pretty cheap. For such a hobby that's so demanding on lights, I would not trust alkaline batteries,


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## gillestugan

Looks good. but a few more scratches i the plastic please would look good  That is some serious testing grounds. Wish we had caves like that here in Sweden.

Guy's dropper: He wrote he used NiMHs not alkalines. And thy are more reliable and practical to use in such environments than Li-Ion. Using Li-ions you must use a hardcase to protect them from mecanical damage that comes from crawling, climging and sqeezing yourself through narrow passages. And a fire in your pocket is the last thing you want when you are in a position where you are unable to reach it.


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## Guy's Dropper

Ok, good. NiMH is a good economical battery type for that application. I should mention, however, that Li-ions are very easy to store safely. If I am carrying them on my person, I store them in either Tube Vaults or Airborne containers. They are the most waterproof and impactproof containers, as far as I can tell.


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## Tobias Bossert

gillestugan said:


> Thank you so much for showing how to wire multiple PT4105 in parallel using one switch for regulating output to all of them.



No, Gille, please look to my circuit diagram carefully!
It is easy to parallel driver boards with C300 or C310, since LED+ is identical with Power+
As far as I understand, it is not possible to parallel those boards with PT4105 easily, because the LED is floating, LED+ and LED- both are not fixed.



> My plan is to build a lamp for caving and general outdoor using two MC-Es. One very wide flood and one narrow.
> I'm probably going to use 4 X PT4105 and the dies wired 2 in series with each pair individually driven.
> This will give me a very wide input range of about 8-18V.



One benefit of MC-E above P7 is that each die can be driven separately. Your application with two MC-E does not need any paralleling of driver boards since you plan anyhow to build four paths each with two dies in series: each one can be driven with its own PT4105.
The efficiency of most boards decresases, when the difference between input voltage and output voltage increases. Therefore it makes no sense to drive two parallel pathes of two serial dies (Vf~7V) with two separate drivers at 18V. It would be more efficient to use only one driver for all of them in series.
Please remember, that switching just single dies off will propably decrease the "beauty" of your beams pattern. The advantage of boards with PT4105 is that they can be dimmed to quite low levels without loss of efficiency. Therefore it is better to dimm all four dies istead of switching then one after the other off. Also the output of all four dies each dimmed to 1/4 of current is higher than of only on die remaining on full current.



> Regarding the housing:
> I've used an aluminium box for a 3X XR-E setup which works very well. It handles the heat well, is waterproof (if o-ring or other seal is used) and is quite cheap. EUR 4.40. Just not as good looking as I wanted. I would prefer an oval housing. Anodised in gold, red or black.
> Here is the box: http://www.conrad.de/goto.php?artikel=522369
> Regards /Gille



Thanks for this link. This cases are very stable, my be I will take it for the next test device to improve mechanical stability. But first I'm waiting for the experiences with the first test device in real life situation of cave expedition...
Regards Tobias


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## gillestugan

Thanks for your input.
And yes, all dies in each led will always see roughly the same current to keep the beam uniform.

I planning on using 11.1V battery packs, which is closer to output voltage of two cells. (I already have 11.1V packs from another headlamp.)

Will use a 2 pole 5 ways rotary switch similar to yours, but I have decided to wire it off-on-on-on-on for both leds, using a mosfet to keep current in the switch low.
I will then use the other pole for selecting levels, using resitors for controlling the "off" and "on" for the leds in the different modes, where "off" will be a led driven at less than 1mA. 
The resistors are wired with diodes in series as in your chart. Thanks, I would probably have gone looking for a bulky 5(6) pole switch if I hadn't seen your chart.


I've also been doing some testing with PTCs for temperature regulations. Replacing the resistor with value 1k8 in your chart with the thermistor.
I haven't decided yet if I want it or not. With it I wouldn't have to worry about cooling, but Im not sure I happy with the indefinite levels I would get. The air temperatures in a cave are stable, but I use headlamps outdoors as well, an it's a big difference between -20 and +25 degrees celcius. Maybe if I find a PTC whith a sharper knee...

I have run into one mayor problem. You know it too well - the optics.
The MC-Es are really not easy to work with. Most optics gives a beem with FWHM of 18-40 degrees. I want one less than 10 degrees and one more than 60 degrees. Haven't found any of them. 
The only narrow ones are 35mm wide and then there is no point in using a MC-E as a 4*XR-E 35mm Ledil cute lens is smaller, more narrow and makes heat sinking easier.
Im interested of 20mm optics, maybe 25mm as I want to keep the housing pocket sized.

Have also been looking at the tiny XP-E leds. Khatod has a 25mm 4*XP-E lens 10 degrees FWHM. Looks good for spot, but I havent been able to buy and try it yet (or seen someone elses beamshots).
The XP-Es as well as the MC-Es are not uniform in colour when used without optics. They are very blue in the middle and very yellow-green further out. (i have only tested the WG tint.) Was hoping to be able to use them for flood without a lens, but the XR-Es are much better.
If you are interested you can find a lot of beam shots of various lenses and reflectors in this thread at MTBR.

So right now I'm trying to decide if I should build a MC-E light with one 15 and one 40 degree reflector with part available, or if I should wait and see if better optics will come for the XP-E.

I haven't got a program to draw circuit schemes, but maybe I will try to find one. Did yours actually have the PT4105E in the component library? 

Regards 
/Gille


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## Barbarin

While I’m working on a headlamp that would be good enough for caving and cave-diving, it won’t be 100% optimal for caving from the point of view described by Tobias and others. As long as he has been kind enough to give me his opinions in my thread I wanted to give you my suggestions here for the project that is being discussed.
 
First of all I would like to link to a excellent post by Kiessling about the importance of flood lights and low levels. 

Clearly, when it comes to really long term use of artificial and self attached lighting, on close distances, a spot, even a well diffused one, can be fatiguing and to some point, that “through hole view” could be even harmful (always on a very long term use).

Definitively a long term use caving headlamp designed for a comfortable use should have a pure flood light.
I've been playing for a while with “zoomable” optics. The problem with those is that at least the ones I have been testing are "pure spot" beams in which you just have the option to choose the angle of the spot, but it is not a beam with a combined spot and corona. 

This picture explains it better.

But, what if we use one zoom and one flood with independent switches and common output control? (Based on two XRE )

We could have all the options described by Tobias:

*1) Normal light for walking and climbing*

FLOOD ON + ZOOM ON. Output and zoom adjusted to needs. (large room, small tube…) From 0,5 to 7 Watts.

*2) Pause light*

FLOOD ON ZOOM OFF. Output to minimum. Less than 0,1 Watts.

*3) Spot to explore deep pits or high shafts*

FLOOD OFF ZOOM ON. Output 100%, zoom adjusted to distance. 3,5 Watts.

*4) As much light as possible for big halls*

FLOOD ON ZOOM ON. Output to 100% Zoom adjusted to distance. 7 Watts.

Now the challenge is how to design this to not need and screwdriver in your hands to adjust easily and fast the beam and output to what is needed each moment. By the now we know that we need three controls. 

1. Output selector.
2. LED selector with three positions ZOOM-FLOOD-ZOOMFLOOD.
3. ZOOM actuator.

What do you think on this?


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## Barbarin

Barbarin said:


> ...This picture explains it better.


 
Obviously I didn't linked any pictures. Here it is:






From left up to right down you can see: 1-4, different degrees of ZOOM. As you can see with this kind of zoom you always have a spot, with near no spill. On picture 5 a pure flood CREE XR-E with no optics at all. Pic 6 is a reflectored single die LED, in which you can see clearly the effect SPOT+Corona.

What I'm suggesting for a caving dedicated light, is the addition of any of the zooms + flood, working together but when on resting time or in "search" (just spot). 

Javier


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## Tobias Bossert

Thank you, Barbarin,
your proposal seems to be a good compromise between number of required independent LEDs and mechanic/optical complexity. I think this is much more flexible approach for cavelight than your 1-LED proposal in your actal thread https://www.candlepowerforums.com/threads/217415
In some way this is an improved Scurion solution (also 2-LED). Scurion combines a bare emittor (P4, not XR-E) with another LED in a narrow beam TIR (Gaggione LL3). 
You replaced the TIR by a pure optic lens which gives the posibility to vary the focus and which doesn't produce spill.
As far as I can see, your new 2-LED solution covers all these light combinations I required a 4-LED solution in my test device: Congratulations!

Unfortunately every benefit (only two optics, LEDs and drivers needed) requires some effort: Your 2-LED solution needs mutch more mechanics than my 4-LED solution.

1) You need to provide a mechanic adjustment of the focus.
When you switch from "work-light" (defocused beam) to "shaft-thrower" (focused), you will have to switch electrically and mechanically! 

2) You need to provide separate declination adjustment of beam and flood
Fortunately no focus change is necessary between "work-light" and "huge-hall"; but in this case you need to readjust the declination of flood with respect to throw, otherwise you will illuminate the floor especially!

I'm no mechanic expert, but as far as I can imagin, the 4-LED solution will get smaller and more lightweight than any adjustable 2-LED approach. And even easier to use too...
But the adjustable 2-LED solution is more universal, because you can vary continuously. The fixed 4-LED solution is restricted to what it was preset.

Tobias


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## Barbarin

Hello Tobias, 

Good points.

For a homemade light the mechanical complexity of this option proposed makes it less viable, but for a industrially developed and made product it could be the way to go if the design is clever and the use intuitive. Even one of the selectors could be removed if we use just a rotary switch with enough positions such as:

1. OFF
2. FLOOD 30 mA (Resting) 10 lm 
3. FLOOD 300 mA (Moving on small pasages ) 90 lm
4. FLOOD+SPOT 300+300 mA (Regular use) 180 lm
5. FLOOD+ SPOT 700+700 mA (Large rooms) 320 lm 
7. SPOT 1400 mA (Search mode) 300 lm

With just one Li-ION 18650 2200 mA runtimes would be like 70 hours, 7 hours, 6 hours, 1,5 hours, 1,5 hours.

Can this be done on a compact desing? To start with two LEDs housing should be smaller than a 4 led one, assuming same construction requirements regarding waterproofness (IP).. Uff, let me think about it during the next days...

Regarding your point 2, I think if you choose the right angle and your flood is wide enough you mneed not adjustment on divergence, as long as you always need light in the floor near you, large or small rooms.

The "Hellmeet light" is not so apropiated for caving as it has more a "raid under any condition" approach than a pure cavediving light.. but you won't get lost on a cave using it.

I'm going to try some pictures.


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## Tobias Bossert

Barbarin said:


> For a homemade light the mechanical complexity of this option proposed makes it less viable, but for a industrially developed and made product it could be the way to go if the design is clever and the use intuitive.



You are completely right, homemade optimum and industrially produced optimum are different!



> Even one of the selectors could be removed if we use just a rotary switch with enough positions such as:
> 1. OFF
> 2. FLOOD 30 mA (Resting) 10 lm
> 3. FLOOD 300 mA (Moving on small pasages ) 90 lm
> 4. FLOOD+SPOT 300+300 mA (Regular use) 180 lm
> 5. FLOOD+ SPOT 700+700 mA (Large rooms) 320 lm
> 7. SPOT 1400 mA (Search mode) 300 lm



It's only 6 positions, same as me too!
The 90lm is very demanding. XR-E R2 is >[email protected] and you will lose some % of light internally too. Flood is o.k. but with the optic lens it would be rather 70...80lm. 
As far as I see, XR-E R2 at the present is availlable in color WG only, too greenish. WC or WD would be more nice, but these are Q5 only. 



> With just one Li-ION 18650 2200 mA runtimes would be like 70 hours, 7 hours, 6 hours, 1,5 hours, 1,5 hours.



70h, 7h, *3.5h*, 1.5h, 1.5h 



> Can this be done on a compact desing? ... Uff, let me think about it during the next days...



I'm verry eager to see whether you can solve these demanding technical problems!

There is another problem I'm still looking for a better solution:
Surion has a bare P4 which glares very strongly. There will be no improvement with respect to glaring when using a XR-E.
I tried to avoid glaring by a combination of LED, wideangle reflector and diffuser lens. It does the job verry well but at the expense of at least 30% light loss.
The problem is, that all known diffusers work well as long as the light passes nearely orthogonally. With large incident angles the losses increase dramatically. For this task I would need domed glass front lens (18mm diameter, 4,5...5,5mm hight depending on glass thickness 1...2mm). If I would get those, I can edge or sand them at the concave side by myself. This would decrease the losses and improve the flood tremendously.

Tobias


----------



## Barbarin

Tobias Bossert said:


> You are completely right, homemade optimum and industrially produced optimum are different!


 
Now I can not avoid to think from a industrial point of view...:shrug:





> It's only 6 positions, same as me too!


 
It seems that is more or lees the number of scenarios we can find when caving.



> The 90lm is very demanding. XR-E R2 is >[email protected] and you will lose some % of light internally too. Flood is o.k. but with the optic lens it would be rather 70...80lm.
> As far as I see, XR-E R2 at the present is availlable in color WG only, too greenish. WC or WD would be more nice, but these are Q5 only.


 
I would not use a optic with a CREE for flood. They are excelent as they come for that purpose.



> 70h, 7h, *3.5h*, 1.5h, 1.5h


 
You are right, it was a typo. What do you think about those runtimes on a battery integrated device?



> I'm verry eager to see whether you can solve these demanding technical problems!


 
According to my first calculations it could be done on something like a prism with the following dimensions:

30x40x90mm if it has integrated battery.Smaller with wire configuration.



> There is another problem I'm still looking for a better solution:
> Surion has a bare P4 which glares very strongly. There will be no improvement with respect to glaring when using a XR-E.
> I tried to avoid glaring by a combination of LED, wideangle reflector and diffuser lens. It does the job verry well but at the expense of at least 30% light loss.


 
Glare is not so bad if not aimed directly to your eyes, so my suggestion is just to paint with black marker or black paint the portion on the lense edge that will produce the glare you want to avoid. 



> The problem is, that all known diffusers work well as long as the light passes nearely orthogonally. With large incident angles the losses increase dramatically. For this task I would need domed glass front lens (18mm diameter, 4,5...5,5mm hight depending on glass thickness 1...2mm). If I would get those, I can edge or sand them at the concave side by myself. This would decrease the losses and improve the flood tremendously.


 
I don't like diffusers either, I think they waste too much light unless you want a very slight diffusion.

I can send you a dome 20-25 mm (ID-=D) for your homemade lamps if you want to.

Regards,

Javier


----------



## Tobias Bossert

Hi Javier,
thanks for your input. The discussion starts now to produce the outcome I hoped for.



Barbarin said:


> I would not use a optic with a CREE for flood. They are excelent as they come for that purpose.



Yes, you are right, Cree XR-E has its own internal lens just giving the optimum pattern for this typ of flood we need for worklight! It's about twice as strong as SSC P4 on axis and avoids the "useless spill" outside of +/-45°. From this point of view we don't need any further optics for it - from this point of view...



> Glare is not so bad if not aimed directly to your eyes, so my suggestion is just to paint with black marker or black paint the portion on the lense edge that will produce the glare you want to avoid.



Excuse my limited English, I think my remark on glaring was not understanable. Glaring yourself is not my problem, this can be solved easily as you said by covering the glaring edge of the front lens with black paint.
Scurion uses SSC P4 behind a plane front lens. The case limits the flood to about +/-70°. So it is unrealistic to avoid glaring your friends by turning your head away when talking with them. Most cavers are of the opinion that this as a big disadvantage of Scurion.
When we use Cree XR-E for flood part of worklight instead, we reduce the problem only slightly, because the angle is still +/-50%.
This is the reason I prefere to enlarge the light source area which can be seen from others. My solution outputs the light from an area larger than 100mm², this does not glar the friends anymore. 



> I don't like diffusers either, I think they waste too much light unless you want a very slight diffusion.



Me too, but they are not as bad when used with light inclining the sanded or etched surface rectangular. With my experience it is achievable to reduce the losses below 10% with that. I'm willing to accept additional 10% of loss to avoid glaring my friends.
With my actual test device I use a plane diffusor, which produce a lot of loss (about 30%) because the inclination angle goes from -45° to +45°. With a spherically domed diffuser (die of XR-E in the center), allmost all light would incline the surface nearely rectangular - and the pattern would be improved additionally!

I found now domed mineral glass for watches with reasonable diameters. Propably these will be too thin and fragile for a caving headamp, but they are good for experiments to study the losses. I hope I can post my results for that in about two weeks. If it holds true and the losses could be reduced accordingly, it's up to you (or whoever will produce such caving lights) to find a robust domed diffusor front lens. 

Thank you, Javier, for the good idea to combine flood and throw with variable power ratio. With this idea, I will try to develop my 4-LED solution further into a 3-LED solution.
All three, the focal part of my work light, the light for huge halls and the shaft-spot in my 4-LED solution are on axis. The focal part of work light and the light for huge halls could be realised with only one device when adding an variable portion of the focused shaft-spot.
Only the diffuse part of the work light is off axis or asymmetric. This I will keep mechanically separate for home made devices, because it is very difficult to realize separately declineable parts of the headlamp.

It will be no problem to find adequate power ratios and to realize them electronically. 



> According to my first calculations it could be done on something like a prism with the following dimensions: 30x40x90mm if it has integrated battery.


 
Oh yes, verry compact for a robust headlamp including the battery and providing optimized beams! 



> Smaller with wire configuration.



Since there are many cavers prefering as less weight at the helmet as possible, this variant will find its users too... 

Regards,
Tobias


----------



## Tobias Bossert

Hi Javier,
I come back to your proposals in post #56 and #57, because they seem to be good ideas.



Barbarin said:


> I've been playing for a while with “zoomable” optics. The problem with those is that at least the ones I have been testing are "pure spot" beams in which you just have the option to choose the angle of the spot, but it is not a beam with a combined spot and corona.



I think this is achievable with pure lens optic only. I also experimented a lot with spherical and aspherical lenses.
For my experience using a single lens, SSC P4 gives nice beam flatness especially with large beam angles. But the losses (side emitted light not catched by the lens) are high and increase when narrowing the beam. You therefore need a "thick" lens with high aperture and with that aberration and internal scattering arrise.
With Cree XR-E the aperture is not so critical, but the beam flatness is poor (sometimes donut) and color tends to separate concentrically.

Your pictures look very nice! Propably you have better lenses than me. What are the smalest (pic 1) and largest (pic 4) FWHM angles you achieved with your zoomable optic?

In case the spreed of angles is huge enough (e.g. 6...60°), we really can think about to use only two light sources and combine them with variing levels (_Javier approach_):

Light A is a pure flood with XRE-like pattern (but not glaring the friends) internally mounted with fixed tilt downwards by about 25...35° with respect to the case.

Light B is a pure zoomable spot without spill internally mounted horizontal with respect to the case.

The tilt of the whole case must be adjustable of course. 

1) Off
2) Pauselight: . . . . . . . .Light A (20mA)
3) Worklight low: . . . . . Light A (80mA)
4) Worklight medium: . Light A (80mA) + Light B (25mA)*
5) Worklight high: . . . . .Light A (320mA) + Light B (100mA)*
6) Short term light: . . . . Light B (1000mA, ) 
max focus => shaft-spot
any angle you like
max spreed => hall-light​
*) The optimum power ratio using a sharp beam to lighten the upper portion of the flood is to be studied first. I'm not shure, whether it is acceptable to have a sharp edge for long time usage. The throw portion must not be too high. The combination I tested so far (spot was XR-E & Carclo 10201), the optimum ratio was about 3 + 1.
During worklight you can focus light B as you like (normally 15...30°)

This lamp needs professional manufacturing, I'm unable to do the mechanics.
____________________________________________________________________

So hand made lamps should go with fix focus lens optic plus one additional TIR with medium or wide beam and spill, as described in my last post:

Light A is a pure flood with XRE-like pattern (but not glaring the friends) internally mounted with fixed tilt downwards by about 25...35° with respect to the case.

Light B is a pure fix focus lens spot without spill internally mounted horizontal with respect to the case.

Light C is a TIR with about 15...25° and spill internally mounted horizontal with respect to the case.

The tilt of the whole case must be adjustable of course. 

1) Off
2) Pauselight: . . . . . . . Light A (20mA)
3) Worklight low: . . . . .Light A (80mA)
4) Worklight high: . . . .Light A (320mA) + Light C (100mA)
5) Shaft-spot: . . . . . . . Light B (1000mA) 
6) Hall-light: . . . . . . . . .Light C (1000mA) + Light B (320mA)

In case we use MC-E & Carclo 10195 (FWHM ~30°) we can increase position 6) to:

6) Hall-light: . . . . . . . . .Light C (3000mA) + Light B (1000mA)

Regards
Tobias


----------



## Tobias Bossert

*Firts report from real life test in a large cave*

*Test report for test device_2*[FONT=&quot]Predefined questions; [/FONT]
report/answers of tester (‘Bucherl’); 
_[FONT=&quot]remarks/conclusions of developer (‘Tobias’)[/FONT]_​ [FONT=&quot]Test environment?[/FONT] 
Four days cave expedition (27. to 30.12.2008) in ‘Tiefkarkluft’ of ‘Hirlatzhöhle’ (Austria)
[FONT=&quot]Situations encountered?[/FONT] 
Fast walking over very long distances; crawling; climbing; cave surveying; rests; bivouac

*1) Pause-light*
Is the pause-light strong enough?
The pause-light of test-device_2 was the only thing which I couldn’t use! It is medium beam and oriented horizontally – impossible to give a look into your backpack and even impossible to see what’s in your food basket. The pause light must be tilt downwards like the diffuse-light in the work-light. It wasn’t possible to decline down my helmet mount (which allows tilting) enough to overcome this problem: inacceptable!

Should the beam be narrower or wider?
Can’t say this by testing – only suppose it: should be wider. I propose to use the diffuse-light in a further dimmed stage as pause-light.
_[FONT=&quot]O.K., I will switch pause-light to diffuse-light in test-device_3![/FONT]_

*2) Work-light*
2a) Absolute intensity
Is the work-light low even too strong for crawling and climbing?
For crawling it is very bright (could be much darker), but also during crawling I sometimes have to look in which direction could be a prolongation. So it doesn’t matter really, that it is very bright during crawling.
Not only the dimension of the room is of interest, but even more the reflectivity of the materials surrounding you. It’s a reasonable compromise.

Is the work-light high strong enough for fast walking on dark ground?
Yes, it is – even if you really “run down” an uneven slope. Camparable to Scurion in its highest setting (bare P4 at 1000 mA)! When you go immediately behind someone with a medium Scurion setting, he gets problems with his own shadows.
 
Does the power ratio between work-light low and high should be smaller or larger?
There seems to be no general answer to this question. It depends upon so many things like power consumption (runtime), your own physiological condition and the situation in the cave. The difference is reasonable at least. The Scurion developers seem to have taken this into account and made the switchable levels programmable. 
My proposal is 1:2 and a third work-light additionally below ‘low’ (about 50% of low) and without ‘light-up’, which will be useful for climbing, crawling and pauses too. And if you have to save energy for some reason, you even can walk with that.
 
_[FONT=&quot]Conclusion for test-device3 (LED currents):[/FONT]_

[FONT=&quot] . . . . . . . . | . . .light-up. . .|. .diffuse-light . |
. . . . . . . . |device_2. .device_3|device_2. .device_3|[/FONT]
 pause-light . . |. 15 mA. . .--- mA | --- mA . . .50 mA |
 work-light low. |. 40 mA. . . 30 mA | 135 mA . . 150 mA |
 work-light high |. 90 mA. . .125 mA | 295 mA . . 250 mA |

_[FONT=&quot]Device_3 pause-light will have an overall output three times higher than device_2. Because the new pause-light will be much wider, the intensity will not be brighter than in the centre of the old one. The Candella values inside the beam (FWHM 90°) will be comparable to the on-axis values of a plane SSC P4 driven with 100mA and thus be sufficient for crawling and slow walking (in absence of other strong lights).[/FONT]_
_[FONT=&quot]Work-light low will have a slightly reduced part of light-up (for light-up device_2 uses 1/4 of the overall consumption, device_3 will use about 1/6 only).[/FONT]_
_[FONT=&quot]Work-light high will have a slightly increased part of light-up (for light-up device_2 uses 1/4 of the overall consumption, device_3 will use about 1/3).[/FONT]_
_[FONT=&quot]For light-up device_2 uses a single chip LED (XR-E) in Carclo 20mm TIR frosted medium (#10211) with FWHM of 20°. Device_3 will use a four chip LED (MC-E) in Carclo 20mm TIR frosted narrow (#10194) or frosted medium (#10195) with FWHM of 24° or 28°. The reason is that we can do without an additional “flood 40° for huge halls”. Which TIR will be used at the end depends upon the beam of the optic: I must have a try first![/FONT]_

2b) Relative intensity
 Does the light-up should be stronger or weeker?
It’s the same as above: there is no general answer – it depends. In small parts of the cave the light-up tends to be too strong, in large parts it could be even stronger too. I propose not to change it, it’s a reasonable compromise.
It makes also a big difference whether you go up or down a slope. For going up you could do without any light-up, but going down its very helpful.
The light-up is very useful during surveying: The diffuse-light is strong enough for the paper to write on it and the light-up enables you to see the contours of the room too.
_[FONT=&quot]See clause 2a. I will not make changes in principle but slightly optimize towards: [/FONT]_
-_[FONT=&quot] pause-light is also for crawling and passing very narrow parts and serves as emergency light too[/FONT]_
-_[FONT=&quot] work-light low is for small and medium parts and/or ascending [/FONT]_
-_[FONT=&quot] work-light high is for medium and large parts and/or descending[/FONT]_

2c) Diffuse-light
 The diffuse-light of device_2 has a FWHM of about 90° and a slowly decreasing spill up to FW of 110°. The device_1 you saw in Obertraun meeting had a FWHM of about 80° and quickly decreasing spill up to FW of 90°.
 Could I reduce the FWHM and the spill (this would increase brightness inside the beam)?
The diffuse-light is good as it is. It must not be wider. May be it could be a little bit narrower (10°?) but it is really desirable to have this very soft “edge” which you do not see during long term usage. 
_[FONT=&quot]I leave the diffuse light as it is – with sleight improvements: Device_2 uses a self etched plane glass lens, which produces much losses far off-axis. Device_3 will use a spherically domed self etched glass lens. With this the “beam” will seem to be wider and flatter when using the same reflector. I compensate this modifying the reflector. So at the end the shape will be similar, but a little bit brighter.[/FONT]_
_[FONT=&quot]The intensity of etching controls the “width of the beam” and also the amount of antiglare effect.[/FONT]_

2d) Light-up
 Device_2 has a light-up with FWHM of 20° with relatively wide and smooth spill (frosted). That one from device_1 you saw at Obertraun meeting had a FWHM of 16° and less dispersed spill (rippled). 
 Should the light-up be narrower or wider?
It’s similar to the the intensity of light-up: for short distances it could be wider and for large distances it could be narrower. Do’nt change it strongly, it’s reasonable.

Should the light up have more or less spill?
The smoother transition between light-up and diffuse-light is much better than the somewhat abrupt one of device_1. Don’t go back to rippled.
We tried to find a combination of flood and throw with Scurion (as recommended by the manufacturer), but for long term usage the spot was annoying and both use go without spot al the time (that means, they use spot transiently in case of watching a huge hall, a long tunnel or a shaft only).
_[FONT=&quot]I will try not to change the pattern as it is. But I have to make it a little bit wider (even smaller than “frosted wide”) because device_3 will use a four chip LED. I will do my very best...[/FONT]_

2e) Glaring
 What’s about glaring of persons face to face? Need we further suppression of glaring?
The glaring is much lower than with Scurion – even comparable to conventional carbide lamp. No further development seems to be necessary.
_[FONT=&quot]O.K., with the domed front lenses it will get even better too.[/FONT]_

*3) Shaft-light*
 Device_1 had a Gaggione Mobdar with SSC P4, delivering a quite similar throw to Scurion (Gaggione LL3 with SSC P4). Additionally I demonstrated a separate thrower Carclo 60mm (#10144) with Luxeon K2 TFFC. You decided, that the extreme thrower would be nice – but it is far away to big to be used in a helmet headlamp. Device_2 now has a bare optical glass lens and the beam is between both systems shown in Obertraun.
 Should the spot be narrower or wider now?
In any case not narrower! I can’t say whether it should be wider or not without testing it.
Scurion has a wider beam (may be about double as wide and somewhat more “soft”). It depends upon the situation whichever is better. To watch a huge hall Surion is better than our narrow beam, but for this task we already have our hall-light which surpasses Scurion by far! For narrow pits, shafts or even huge cleft-rooms our thrower is better. 
 _[FONT=&quot]The shaft-light of device_2 is a single optical glass lens. The beam angle depends on the distance between LED and lens. Device_2 provides FWHM of about 4,3° (80cm Ø in 10m distance). It can be changed to nearly any other angle as desired. With the lens I used (AncorOptics AX 77183) the beam is restricted to about 2m Ø in 10m distance, beyond that arise a week donut. The final decision upon the angle can be taken during mounting the device. The maximum on-axis brightness is reached at about 140cm Ø in 10m distance, astonishingly not with the narrowest beam. Device_3 will provide this adjustment. [/FONT]_

Device_2 provides nearly no spill. Would it be desirable to get some spill (less is impossible)?
No, please no spill at all for the shaft-light. 
_[FONT=&quot]I will not change it![/FONT]_

Does the sharp and coloured edge of the beam annoy?
The sharp edge of the beam is quite good for our applications. 
Additionally to looking into deep pits you can assist a climber without glaring him! 
_[FONT=&quot]I will not change it![/FONT]_

*4) Hall-light*
 It’s unchanged since Obertraun meeting.
 Is the beam sufficiently smooth (there is a week donut visible on white walls)?
The beam seemed smooth when using it in the cave. Don’t change.

Could I make the beam a bit wider (and darker in the centre accordingly; this may reduce the size of the reflector)?
The beam is good, don’t change it.
_[FONT=&quot]Device_3 will come without the separate hall-light of device_2. The compensation of that will be the improved light-up, which will allow up to 700lm now, the separate hall-light of device_2 allowed up t0 900lm. The pattern will be a bit different but even much better than all Scurion can provide too! [/FONT]_

*5) Consumption*
 How many battery packs did you needed for this four days?
I took four some years old packs with me, each consisting of 6 NiMH cells with 2000mAh.
I used the capacity of a bit more than 2 packs only.
Pack 1: about 19h work-light low and additionally many transient uses of work-light high, hall-light and shaft-light.
Pack 2: about 13h work-light low, 2h work-light high and additionally many transient uses of hall-light and shaft-light.
Pack 3: inserted half an hour before leaving the cave, so it’s still nearly unused.

How many Ah and/or Wh you used?
About 4.2Ah at nominal 7.2V, that’s about 30Wh.
_[FONT=&quot]The power consumption of the device itself will not change. But realize that you used a test device and didn’t know at the beginning, whether your battery packs will be sufficient. When you are used this lamp, may be you will use work-light high more often.[/FONT]_

How many battery packs used the Scurion users. 
Each of them had two packs, each consisting of 4 LiIon cells with 2600mAh.
Johann was using its Scurion very restrictively and arrived daylight with its first pack.
The fist pack of Clemens holds three of four days. When he changed the pack, he was astonished that the second one didn’t work though it was charged freshly. But he had luck, because Johan could give him his second pack.
_[FONT=&quot]As a rough assumption we can say, that Johann used less than 38Wh and Clemens used about 50Wh.[/FONT]_

*[FONT=&quot]6) Summary[/FONT]*


This pause-light is unsuitable and should be improved. _[FONT=&quot]Yes, this will be done[/FONT]_
The concept of tilt diffuse-light and smooth horizontal light-up is optimal. _[FONT=&quot]Remains unchanged[/FONT]_
The shaft-light is very good. _[FONT=&quot]Remains unchanged. The beam angle can be chosen during production[/FONT]_
[FONT=&quot]The hall-light is impressive, I additionally used it for open day in Koppenbrüllerhöhle. It’s much brighter than the fixed halogen lamp installation.
[/FONT][FONT=&quot]It’s really nice to have – but it’s luxury and not ‘must have’ for strenuous expeditions. You can use it for video and photo captures and for guided tours too. [/FONT][FONT=&quot]
In case we could simplify the headlamp by this (smaller, less weight and costs), leave it away.[/FONT]
_[FONT=&quot]O.K., this is the reason why I switch now to a three LED approach! There is still a hall-light in device_3, but it uses no longer separate hardware.[/FONT]_
_[FONT=&quot]Without the separate hardware for the hall-light the components must not reside so “condensed” in the case. This simplifies the mounting of hand made devices.[/FONT]_
_[FONT=&quot]All cavers having seen this test device_2 so far – even those who already bought a Scurion - would like to have a lamp with such features. But I’m unable to produce such things by hand (it would take me about two working days to build each in my cellar), so we should look for someone now being able to produce a small amount of copies of test device_3.

But first test device_3 must be finished! So work is going on...
[/FONT]_


----------



## gillestugan

Thank you for your extensive report! 

Regarding the pause-light, why cant you use the work light as pause light? If you tilt the pause light downward they will probably have about the same angle, so all you need is to adjust the output by adding another resistor (and diode).

You would then have space for the hall light  The MC-E works very well with the 22mm BOOM reflectors from ledil. As you only is going to use it on full you may save some space by wiring it in serial and using a step-up driver like the Shark. 
Maybe you already have thought of something like this as you write:


Tobias Bossert said:


> _[FONT=&quot]Device_3 will come without the separate hall-light of device_2. The compensation of that will be the improved light-up, which will allow up to 700lm now, the separate hall-light of device_2 allowed up t0 900lm. The pattern will be a bit different but even much better than all Scurion can provide too![/FONT]__[FONT=&quot]
> [/FONT]_


I dont understand how you will achieve this without separate hardware for getting such high output, but you seem to have something in mind.

One fantastic thing with the leds is the ability choose very low levels AND very high.
I was hoping to use two MC-Es, one flood and one spot, and use the flood at highest level for hall-light, but it seems impossible to get satisfying beams with the MC-E.


----------



## Tobias Bossert

Hi Gille,
I think I should clarify some words I have used.
There are 4 light sources in the headlamp as shown in the picture:






One of them - diffuse-light - is tilt downwards. Three of them are not tilt, they are mounted horizontal to the case: shaft-light, light-up and hall-light.
Shaft-light (XR-E and optical lens) is used alone in switch position 5.
Hall-light (SSC P7, OP reflector and diffuser frontlens) is used allone in position 6.
Light-up (XR-E and Carclo 10201) is used in three different switch positions:
in switch position 2 alone as pause-light
in switch position 3 together with diffuse-light as work-light low
in switch position 4 together with diffuse-light as work-light high​Diffuse-light is never used alone in test device_2, it's always used together with light-up as work-light.

This means I can tilt downwards the whole case only, because all four lights in it are fixed with respect to the case. I cannot preset the light-up with any tilt, because than it will no more do its job for worklight: its job is to lighten up the upper area of the wide beam of diffuse-light).



gillestugan said:


> Regarding the pause-light, why cant you use the work light as pause light? If you tilt the pause light downward they will probably have about the same angle, so all you need is to adjust the output by adding another resistor (and diode).


 
I plan now just to swap the usage in the switch position 2 (pause-light) to use the diffuse-light alone rather than the light-up allone.

Because the beam patterns of light-up and hall-light are not to much different and the strong hall-light anyhow is luxury, I plan to use the light-up allone additionally as hall-light too. Naturally light-up isn't optimized for this additional task, but I think it will work satisfyingly. With MC-E instead of XR-E in the new version of light-up I need another optic naturally, e.g. Carclo 10194 or 10195. If both donot work well, I will try the BOOM reflectors from Ledil.



> As you only is going to use it on full you may save some space by wiring it in serial and using a step-up driver like the Shark.


 
Good idea, thank you, I will think about!

Regards
Tobias


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## Barbarin

I'm having now a few days vacations, but just received some pictures testing zoom optics on caving. I asked my friends to test no optics + optics at the same time, but it was not possible. 

As the pictures and testing are very related to Barbolight products I have posted the results on a differente thread, but you may find it interesting as they come to explain better the approach of caving headlamp with this capability.

Javier


----------



## gillestugan

Sorry, I forgot it was in use in your two-beam worklight setup... 
Sounds like a great idea to swap the usage in the switch position.
Regarding the MC-E optics I would not recommend the 10194 as it has a bad dark cross. It is even worse in real life than in carclos beamshot. 
The 10195 is smoothest of the carclo 20mm optics, I like it, but it is very wide. Hotspot is about 25 degrees with a 30 degree corona. You can find a wall beamshot taken from 2,2m in this thread.
Beamshots of Boom can be found in the same thread and also in this massive test by IFOR at MTBR.

What shematics program did you use? I started drawing in LTspice but couldn't find any rotary switches in the component library.

That cable looks nice. Is it silicone insulated? Oh how nice cables makes me drool


----------



## Barbarin

Well, it is time to work again on this project, after some vacation time.

Tobias, do you want me to send you some optics?

I'm sure if you try them that you will agree with the idea of the two LED caving headlamp.

Regarding the electronics it is not difficult to make a custom drive, but we should reach a quantity to get it at reasonable prices. I'm decided to start this project not as a Barbolight one, but as personal with the CPF'ers who are interested on it, so if we can have a starting point regarding settings, numbre of LEDs, and some basics, that would help a lot.

Regards, 

Javier


----------



## gillestugan

Javier, your zoom optics seems very nice, but are they small enough? From your pictures of the U-04 ZOOM it seems to be quite large. 

If small and light enough I believe it would work perfect in a 2 led setup. (I prefer ultrawide without hotspot, so 2 leds setup is fine.)

Have you tried it with a MC-E or P7? probably not working, but i have to ask. Higher output would make the lamp more versalite and you would be able to sell it to many others than cavers. It would for example be great as a helmet lamp, bikelight or orienteering lamp. The ability to zoom would make it far superior to almost any high-end headlamp on the market, for example the €400 Petzl Ultra, the Silva Alpha or the Mila Nova.


----------



## Barbarin

gillestugan said:


> Javier, your zoom optics seems very nice, but are they small enough? From your pictures of the U-04 ZOOM it seems to be quite large.


 
Hello Gillestugan. Is not that big, just 29 mm. 



> If small and light enough I believe it would work perfect in a 2 led setup. (I prefer ultrawide without hotspot, so 2 leds setup is fine.)


 
I'm sure we can get everything we need with just two LEDs.



> Have you tried it with a MC-E or P7? probably not working, but i have to ask. Higher output would make the lamp more versalite and you would be able to sell it to many others than cavers. It would for example be great as a helmet lamp, bikelight or orienteering lamp. The ability to zoom would make it far superior to almost any high-end headlamp on the market, for example the €400 Petzl Ultra, the Silva Alpha or the Mila Nova.


 
Tried, and yes, it doesn't work. It produces an awfull "window". Not very good job collimating neither spreading. Definetively not quad chip freindly. 

Looking at the picture I posted last day you really think we need more than two LEDs? We had more than enough to beat a 40mm carbide flame, so keeping things within a reason, I think two LEDs at 700 mA each one would be more than enough for 99,5% of the situations.. and it makes no sense having weight, complexity and cost in your head for 0,5% of the situations, while you can carry a handheld flashlight for that moments. 

I'm not thinking on this project as "Barbolight" but as "Barbarin" so by now I want to keep it away from business side. If we go for it it will be this way, more like a modding project. Meanwhile it will be more than interesting to keep on talking here about what we cavers do really need.

Javier


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## Barbarin

I made this simple drawing to show you more graphically this concept of "beam pattern selectable headlight"

Hope you like it.

Javier


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## gillestugan

You are right, sorry for going off topic. 2X3W is definitely enough for caving. Especially for caving here in Sweden, haha.

29mm sounds great. Too small is not good as it probably would be hard to adjust focus with gloves on.

Khatod has some ultrawide optics that looks good on the paper. The 21mm 70 degree KEPL120908 and the 8.5mm 60 degree PL111806. I will try to get them to try them out. Both are very shallow and would not take much space inside the housing.

Im not too happy with the performance of a bare XR-E. Colour uniformity is not so good when driven at low levels. The WG tinted I have for testing gets very green/brownish to the sides and bluish in the middle. This gets better when driven att high level. 
The problem can be avoided by using PWM regulation, but then I need a driver with custom programmed levels and I have no knowledge in how to program the pics common on cheap PWM controlled drivers.


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## Barbarin

gillestugan said:


> You are right, sorry for going off topic. 2X3W is definitely enough for caving. Especially for caving here in Sweden, haha.


 
Not so off-topic. I sincerely think that any headlamp wiith 200-300 lm is enough for most activities, not just caving. Of course we all would like the ouput and runtime of the sun, with the size of a nut.




> 29mm sounds great. Too small is not good as it probably would be hard to adjust focus with gloves on.


 
At the end if you consider the housing and the o-rings it will be like 40 mm OD.



> Khatod has some ultrawide optics that looks good on the paper. The 21mm 70 degree KEPL120908 and the 8.5mm 60 degree PL111806. I will try to get them to try them out. Both are very shallow and would not take much space inside the housing.


 
According to my testings any beam narrower than 110º is less than confortable atthe end of some hours, as it will force your neck.



> Im not too happy with the performance of a bare XR-E. Colour uniformity is not so good when driven at low levels. The WG tinted I have for testing gets very green/brownish to the sides and bluish in the middle. This gets better when driven att high level.


 
I agree, but from a realistic point of view those are "taxes" we are going to pay anyway. I mean that unfortunately as long as the technology is by now what it is -and I think is amazing compared to just three years ago- a CREE with no optics is one of the best things we can find anywhere, and as Tobias pointed, its "glare" is one important defect that we should try to fix even paying some loose on efficiency.

The Nirvana of Caving Headlamps ( I borrowed this from Tobias too  ) is not achievable with today technology, but our mission in this thread is to get the best with the technology we have. Even if it is not perfect from a utopist point of view. 



> The problem can be avoided by using PWM regulation, but then I need a driver with custom programmed levels and I have no knowledge in how to program the pics common on cheap PWM controlled drivers.


 
Well, the idea here would be to make a custom driver capable of driving two LEDs at the same time with different levels of current, and controlled with a rotary switch with 6, 7 or even 8 positions. In order to have such a design done we must start an interest list, but, it should be after we agree in how many levels and how many LEDs... and just if we can get enough people to make it viable and not too expensive for just a few.


Javier


----------



## gillestugan

Barbarin said:


> According to my testings any beam narrower than 110º is less than confortable atthe end of some hours, as it will force your neck.
> Javier



Mmm . you are probably right, I used a 80 degree and thought it was perfect. But that was from comparing it to a 40 degree lamp. And those bad colours from a bare XR-E emitter are actually hard to see as they are far out in periferic vision. 
I measured my field of vision some time ago. About 85 degrees lateral and 150 degrees horizontal. But my two-eyed horizontal is only 65 degrees.
Hmm, how about using two lamps overlapping each other the in the same area as the eyes? I will do some testing. Probably not a good idea, but Im curious. 

I have also tried the XP-E as bare emitter. It is more uniform in intensity than the XR-E and it's 120 degrees. Very similar to the SSC P4. I didn't measure intensity, but it looked seemed almost half as bright as the XR-E at the same current. But I like how small it is. The dome is only 2,5mm in diameter.

/Anders Gille


----------



## uk_caver

gillestugan said:


> Mmm . you are probably right, I used a 80 degree and thought it was perfect. But that was from comparing it to a 40 degree lamp. And those bad colours from a bare XR-E emitter are actually hard to see as they are far out in periferic vision.


At least at lower power levels, on the extreme edges of a spread beam where light levels fade off, it's possible to have light levels dropping to the point where colour vision just doesn't work well because there simply isn't enough light.


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## hank

Good for you for starting this topic.

I have half a dozen carbide lamps, some from my caving days, and a few more I've picked up at garage sales. If I ever come up with any fresh carbide, I'll pull them out and do some beamshots. They are still awesome light sources.

It would be nice to see measurements of brightness for actual working carbide lamps to compare to the LEDs.

I've always thought that someone could take a carbide lamp reflector, fit a string of LED emitters where the flame sits, and have a stunningly bright light. It's the 2" or 4" or 6" reflector that really helps. Even thought about hiding a set of batteries and a driver inside a carbide lamp body -- but could never bring myself to gutting one, as they all still work.


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## uk_caver

hank said:


> I've always thought that someone could take a carbide lamp reflector, fit a string of LED emitters where the flame sits, and have a stunningly bright light. It's the 2" or 4" or 6" reflector that really helps. Even thought about hiding a set of batteries and a driver inside a carbide lamp body -- but could never bring myself to gutting one, as they all still work.


I'd thought of doing a retro-mod to one of the small 'Premier' carbide caplamps that some cavers used to use here, maybe having the water-control lever as a brightness control.
I suppose one or more LEDs could be fired backwards into the [typically shallow] reflector, but I think the reflectors I've seen are understandably just spherical, rather than parabolic, so they wouldn't give a tight beam.


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## gillestugan

uk_caver said:


> I suppose one or more LEDs could be fired backwards into the [typically shallow] reflector,.


One of the real advantages of the carbide lamp is its wide beam, if using total reflection by pointing the led into the reflector you will get little spill. If you point it forward you will get a more carbide looking beam.



hank said:


> It would be nice to see measurements of brightness for actual working carbide lamps to compare to the LEDs.



There is actually a link to such comparison in this thread. Barbarin has posted interesting beamshots from a cave. One 3W cree Led without reflector against one carbide lamp. The carbide lamp doesn't have a chance.
This is actually not a surprise as a carbide lamp have a output of 35-100 lumens. (reference) Normally around 50-60 lumen and most of those lumens are spread 200 degrees unless you have a really big and shiny reflector. So 200+ lumens at 80-90 degrees from a LED sure makes a difference.


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## uk_caver

gillestugan said:


> One of the real advantages of the carbide lamp is its wide beam, if using total reflection by pointing the led into the reflector you will get little spill. If you point it forward you will get a more carbide looking beam.


If you point it forwards, next to nothing would hit a shallow reflector.

The carbide reflectors I've seen on the smaller caplamps are sections of a sphere, rather than parabolic - they were only ever designed to reflect a flame that had significant length, rather than a point source, and to avoid wasting light backwards, so a spherical-section reflector was fine, and rather easier to make.
They're also typically not highly polished, so back-firing one or more LEDs into one would probably still give a decent flood, without having a dazzling naked LED to look at.



gillestugan said:


> There is actually a link to such comparison in this thread. Barbarin has posted interesting beamshots from a cave. One 3W cree Led without reflector against one carbide lamp. The carbide lamp doesn't have a chance.
> This is actually not a surprise as a carbide lamp have a output of 35-100 lumens. (reference) Normally around 50-60 lumen and most of those lumens are spread 200 degrees unless you have a really big and shiny reflector. So 200+ lumens at 80-90 degrees from a LED sure makes a difference.


_*Some*_ carbide lights are quoted as having an output of 35-100 lumens, but I suspect a proper remote-generator light would be rather brighter than that, at least when turned up for short bursts of extra light when required.

In my experience with carbide, the main failings were the expense and practical inconvenience of keeping the light supplied with carbide and water.
That practical side made it a clearly good move to switch to LED lighting, (particularly for extended expedition use), even when I was making my first lights with ~20lm/W Luxeon Is.
However, I'm sure that most people who used carbide still miss the warmth of the light, not to mention the wonderful heat of a generator clamped between the thighs while sitting around in the small hours in a cave that's still basically at freezing point even in August.


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## gillestugan

Yes, the lumen output is of a carbide lamp is more than enough in most situations. And with a 10cm flame you probably get more than 100Lm. But that is really unimportant. I was just trying to make a comparison for hank.
Regarding the pointed forward led: Some light do will hit the reflector. If the 4" premier reflector is 20m deep it gives an angle from bottom to rims of about 130 degrees. I you put a SSC P4 in the middle 12% of the light would still hit the reflector. (you,re right, it's useless.) And if pointing it towards and old reflector you will probably get a diffused beam, It'll be "almost" like an orange peel reflector, just that is made out of oxide and chrome peel  
And yes. Nothing I've seen beats the colour rendition from a carbide lamp. But its getting better. I have a 3000k cree in a petzl micro mod that is very warm, just a little brownish in the tint.

Good idea with the water-control lever for brightness. Many lights have fixed steps, which would make it very convenient if used with a potentiometer. (for example a PT4150 driver) And keeping the batteries loose inside the carbide container will give you the rattle of a full light. That would actually be funny, but I too would not be able to bring myself to gutting one. Not a Premier, but maybe a Justrite... hehe


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## Barbarin

I've been thinking about a "CarbiLED" too. In fact that would be the most similar to a pure flood style light. (as carbide is)

Let's imagine. Using a 70 mm diameter alloy disc , 7-8 mm thick, with some finning on the back would allow enough heatsink . A protective "frozen" polycarbonate lens like 3 mm for a single XR-E (maybe 3 in series to reduce glare and improve efficiency) , and the batteries placed on a kind of "generator" holding 4x18650's or alternatively 8 x CR123 , with a potentiometer from 1% to 100% ( 10-1400 mA). Runtimes from 6 hours at 300 lm;24 hours if we just need to be over a good carbide specs (more than 100 lm) ; and ranging from one day to two weeks on low levels.

The generator hanging from your waist, hitting every rock, that flat disc on your helmet will look like an old style flamme reflector, the control next to your waist, the cable... That would be for sure really similar to carbide. (Not _replacement_, but _similar_). And simple and "cheap"* to make. Sorry, no smell, no heat.

In fact making a pure flood light will make things really easier... and if you just need a "thrower" for very short moments, why don't carry it on a pouch?? Just a different approach. 

Not the purpose of this thread, as the idea is to get the best lamp available designed for the needs of caving, with the technology we have today. But just wanted to talk about it.

Javier

_*It could be made cheaper if using no driver, DD resistored down with the potentiomenter, and a 3 X D NiMH battery pack with __this battery holder__ on the 3D version and "moddified" to be IP67 at least.(The C version looks better and can be used for 26650's )._


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## gillestugan

Regarding the anti-glare: 
I just made some tests with a piece of lightly frosted glass from a reflector bulb. The loss was very small and it reduced the glare significantly. Unfortunately it is frosted on the inside, so it wont be possible to glue it on top of the led with optical resin, and it is very fragile in it self. Would be nice to find some kind of thicker and curved lens that is just as lightly frosted.
Do you think it would be possible to diffuse the Carclo 10403 120 deg Bubble optics? 
The Khatod PLJT20 20mm Diffused dome has been mentioned, but I am afraid it will give too low output. Especially as it is 170 degrees. The test report doesn't give any information on the output, as the output the led used in the test is not specified. 

EDIT: I just saw there is. But I cant understand and match the numbers to what is said in the text. Someone please explain. How much lower is the lux level of the LED with the lens on? 1/3,2?


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## Tobias Bossert

I will complete the test report. Gottfried, the tester of test device_2 ('Bucherl'), took some photos. With the link you can compare Scurion P4, Petzl Ultra and my test device_2 (Tobi) side by side.

http://www.hirlatz.at/lampenvergleich.html

"Anmerkung 1:" = Note 1
*"comparison of light distribution 1
*

*left: "Scurion P4" flood on level 3,
right: "Tobi 1" work-light low
*

The light of Scurion decreases strongly with distance, with Tobi's worklight you can see more far. This is achieved by the light-up with smooth transition."


"Anmerkung 2" = Note 2


It is the same text but comparing Scurion P4 maximum flood (level 4) with Tobi's work-light high.


(_Comment: Please realize that level 4 of Scurion is about 1A to the LED, but my work-light is 295mA + 91mA only.)_


The room in the cave is covered with very dark loam, absorbing a lot of light. The caver stands immediately beside a wall (left to him). The floor decends slowly, increase again a little bit and - in a distance of about 15m - falls again and thus is hidden. The wall at the other side of the large room is far away. With the adapted eye you can see it with each light ghostly, but in the photos with fixed exposure it seems to be totally black - with the exception of my shaft-light.

My personal conclusion from these photos is, that it is NOT possible to use a two-LED construction with fixed beams! For normal use as a work-light, a relativly narrow beam makes no sense - even when combined with a diffuse light: You need a very soft transition from beam to flood and the beam should not reside in the centrum of the flood.

I'm verry interested in Javiers two-LED solution with zoom - but I'm jet not convinced that the transition of the superposition of both parts would be smooth enough to use it round the clock. I'm not shure whether the two-LED solution will be easyer to construct and will have lower weight as the three-LED solution with fixed diffuse/medium-beam/extra-narrow. 

But never the less, I'm very eager to see some photos from Javier dealing with this. He is experienced in manufacturing and he also convinced me with his zoom-light: Much better than all I have seen in the past.

I agree with the schematic drawings of Javier completely: That's what we need.

At the moment I'm still looking for spherically domed front glass with diameter 18 to 20mm and dome height of 4 to 5 mm (spherical cap with 90 deg opening) to make some experiments with domed diffusers. This diffused light would be need to avoid glaring anyhow, whether we end up with a two-LED or with a three-LED solution.

Tobias


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## uk_caver

Tobias Bossert said:


> My personal conclusion from these photos is, that it is NOT possible to use a two-LED construction with fixed beams! For normal use as a work-light, a relativly narrow beam makes no sense - even when combined with a diffuse light: You need a very soft transition from beam to flood and the beam should not reside in the centrum of the flood.


Maybe it's not *ideal*, but a fixed two-beam solution is not only possible, it's what most people would consider as good enough.
If you mix a flood beam with a rather narrow spot, _even a spot that's really too narrow for optimal floor-lighting close-up *and* with a fairly defined edge_, that still seems to work as a usable light, since the flood lights up nearby things adequately, if not perfectly.



Tobias Bossert said:


> At the moment I'm still looking for spherically domed front glass with diameter 18 to 20mm and dome height of 4 to 5 mm (spherical cap with 90 deg opening) to make some experiments with domed diffusers. This diffused light would be need to avoid glaring anyhow, whether we end up with a two-LED or with a three-LED solution.Tobias


Practically speaking, I think even having a small and somewhat matte 'reflector' round a flood LED *might* make the glare problem less severe.
Though I'm only speaking from a subjective viewpoint, after I (and most people I cave with) moved from using naked LEDs for flood to LEDs with a small reflective collar, I got less feeling of the other people's flood LEDs being annoyingly glaring.

Possibly it's just that a larger source is somehow easier to avoid looking at than a bare LED, possibly it's just that over time I got gradually better at avoidong looking at other people's lights and the small reflectors had nothing to do with it.
However, when _making_ lights, I do find that there's something about naked LEDs that just doesn't seem to annoy my eyes enough to make me automatically look away from them.
I wouldn't be surprised if there's some kind of brightness-avoiding reflex that isn't properly triggered by very small sources


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## gillestugan

uk_caver said:


> Possibly it's just that a larger source is somehow easier to avoid looking at than a bare LED, possibly it's just that over time I got gradually better at avoidong looking at other people's lights and the small reflectors had nothing to do with it.


The smaller the light source is, the smaller is the area it is hitting on the retina when focused by the eye. The smaller the area the lumens hit, the brighter and more annoying it it is to the eye.
This is a problem when you want to make a small and light lamp, as you ideally would have a very large dome on your head 

Looking at the pictures (thank you Tobias!) I agree that it is not working very well with the two lamp system. That is with those very narrow optics. 

I still think you could get satisfying results with only two lamps, but then I would choose a wider spot and softer edge, around 10 degrees. Of course this gives a loss in shaft lighting performance, but it is not often you have to look down those terrible deep shafts. You usually know beforehand if the caves have shafts like that and can carry a small CR123a handheld for those moments. But then, one Boom medium on a MC-E for hall light would also be very nice to have.


----------



## uk_caver

gillestugan said:


> The smaller the light source is, the smaller is the area it is hitting on the retina when focused by the eye. The smaller the area the lumens hit, the brighter and more annoying it it is to the eye.
> This is a problem when you want to make a small and light lamp, as you ideally would have a very large dome on your head.


I take your point, however, I'm talking about surrounding flood LEDs with small semi-matte reflectors, not optics or diffusers.
With a small reflector, someone looking at the light from within ~50 degrees of the lamp axis can still see the naked LED just as before, and just as bright as before, only now with a surrounding area of lit reflector. That does _seem_ to be less dazzling, even though the peak brightness on the retina is the same as previously - possibly it's just easier to automatically avoid looking at.


----------



## gillestugan

Thanks for the clarification, I thought you meant the light reflected by the orange peel reflector. I see your point and agree with you, although a large diffused lens is much less annoying. I have no idea of the cause of the effect with the reflector, it may very well be like you say that the very small sources doesn't trigger the reflexes as it should. Sometimes body (and mind) works in strange ways. The pain caused by dazzle in one eye will for example get lower if you close the other eye. This is really weird.
When talking about glare: Older people suffer more from glare than young people as may take them 3 times as long to recover from it, so if you feel like shining someone in the eyes- go for the youngest.  
One thing to consider is that blue light gives a more annoying glare than warmer tints, compared at same brightness level. Another reason to go for a warmer tint... I am a big fan of neutral-warm tints.


----------



## Tobias Bossert

uk_caver said:


> I take your point, however, I'm talking about surrounding flood LEDs with small semi-matte reflectors, not optics or diffusers.
> With a small reflector, someone looking at the light from within ~50 degrees of the lamp axis can still see the naked LED just as before, and just as bright as before, only now with a surrounding area of lit reflector. That does _seem_ to be less dazzling, even though the peak brightness on the retina is the same as previously - possibly it's just easier to automatically avoid looking at.



I also made tests with semi-matte reflektors. This works relatively fine with SSC P4 but helps not really with Cree XR-E, since the reflector is hit by a too small fraction of the overall flux when you use an ful width angle of 90 deg. Than the reflector gathers the yellow-greenisch surrounding of the original beam of the XR-E only.

And there is another problem with "only reflector": You get a visible edge!

Therefore I remain so far by the solution of test device_2: XR-E plus Carclo wide angle reflector plus diffuser front lens. This works fine, it gives about the same spatial distribution as a bare XR-E but glaring is reduced dramatically. And the diffuser - I used a plane glass lens etched on the inner side - guarantees that there is no visible edge.


----------



## uk_caver

Tobias Bossert said:


> I also made tests with semi-matte reflektors. This works relatively fine with SSC P4 but helps not really with Cree XR-E, since the reflector is hit by a too small fraction of the overall flux when you use an ful width angle of 90 deg. Than the reflector gathers the yellow-greenisch surrounding of the original beam of the XR-E only.



That's true - I tend to use SSCs most of the time since they work better for me in my layout than the more centrally-biased Cree.
I think that adding a small collar to an SSC can give a nicer flood beam than a naked Cree, while also increasing the apparent size.


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## gillestugan

Ledil is coming up with a new lens that looks quite interesting. Twiddle. It has a tiltable diffused lens and will be available in a wide version, but there is no specs of the wide on their website. I emailed them and asked but they said it will take a few weeks until they have the specs, but tefficiency will be over 85%. It probably will be too narrow, but the combination of a tiltable head and diffused lens caught my attention.


----------



## Barbarin

Tobias Bossert said:


> I will complete the test report. Gottfried, the tester of test device_2 ('Bucherl'), took some photos. With the link you can compare Scurion P4, Petzl Ultra and my test device_2 (Tobi) side by side.
> 
> http://www.hirlatz.at/lampenvergleich.html
> 
> "Anmerkung 1:" = Note 1
> *"comparison of light distribution 1*
> 
> 
> *left: "Scurion P4" flood on level 3,*
> *right: "Tobi 1" work-light low*
> 
> 
> The light of Scurion decreases strongly with distance, with Tobi's worklight you can see more far. This is achieved by the light-up with smooth transition."
> 
> 
> "Anmerkung 2" = Note 2
> 
> 
> It is the same text but comparing Scurion P4 maximum flood (level 4) with Tobi's work-light high.
> 
> 
> (_Comment: Please realize that level 4 of Scurion is about 1A to the LED, but my work-light is 295mA + 91mA only.)_
> 
> 
> The room in the cave is covered with very dark loam, absorbing a lot of light. The caver stands immediately beside a wall (left to him). The floor decends slowly, increase again a little bit and - in a distance of about 15m - falls again and thus is hidden. The wall at the other side of the large room is far away. With the adapted eye you can see it with each light ghostly, but in the photos with fixed exposure it seems to be totally black - with the exception of my shaft-light.
> 
> My personal conclusion from these photos is, that it is NOT possible to use a two-LED construction with fixed beams! For normal use as a work-light, a relativly narrow beam makes no sense - even when combined with a diffuse light: You need a very soft transition from beam to flood and the beam should not reside in the centrum of the flood.
> 
> I'm verry interested in Javiers two-LED solution with zoom - but I'm jet not convinced that the transition of the superposition of both parts would be smooth enough to use it round the clock. I'm not shure whether the two-LED solution will be easyer to construct and will have lower weight as the three-LED solution with fixed diffuse/medium-beam/extra-narrow.
> 
> But never the less, I'm very eager to see some photos from Javier dealing with this. He is experienced in manufacturing and he also convinced me with his zoom-light: Much better than all I have seen in the past.
> 
> I agree with the schematic drawings of Javier completely: That's what we need.
> 
> At the moment I'm still looking for spherically domed front glass with diameter 18 to 20mm and dome height of 4 to 5 mm (spherical cap with 90 deg opening) to make some experiments with domed diffusers. This diffused light would be need to avoid glaring anyhow, whether we end up with a two-LED or with a three-LED solution.
> 
> Tobias


 
Great job!!! Makes my comparison to look like a child work....

This weekend there will be more real cave testing, so I hope to publish pictures by Monday. This time we will test the TWO LED configuration, with different levels of zooming. 

Regarding your concerns about blinding your own friends, I think that won't happen with low level pure flood, even with a non diffused CREE... and when it comes to "work light" it is near impossible to avoid if you look at their eyes. I just believe that warmer colors, with less "bluish-greenish" tints should help to reduce the glaring effect, as those colors are the real scotopic vision killers. So according to this, what do you preffer?

1. Use cool white (high lm/watt) and diffusers (efficiency lose) to reduce glare.

2. Use warm white (lower lm/watt) no diffuser. You get better higher CRI, but you need more energy to get the same light.

3. Cool white, no difusser. On a cave efficiency is the priority, above CRI. Less weight, more light. Glare is unavoidable anyway, so will try to not look directly to my friends when work light is on.

What do you think, guys?

Javier


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## Tobias Bossert

I just found a sherical diffuser (Khatod PLJT 35 and PLJT 35/02) which I will try to modify:

http://www.optomarket.com/jsp/index.jsp?p_gadgetURL=pagemapping.jsp%3Fid%3Dcatalog_illus&p_contentTopic=&pocs_bnav=yes&p_containerTopic=0000121203&p_Navigator=0000043212|0000043244|0000121203

It is just a hemisphere made from poly carbonate, outer diameter is 30.4mm and inner diameter is 24.4mm, so the material is 3mm thick.
There are two types. One is extremely milky (PLJT 35) and the oher one (PLJT 35/02) they call "transparent". I will test both of them.
The modification will be lathing (or sanding) it down to a hight of about 6..7mm remaining a spherical cap with an opening angle of about 90 deg, an inner diameter of 17..19mm and an outer diameter of 23..26mm.

I guess the milky type diffuses much to strong. 
In case the "transparent" one diffuses to weak, I will sand blast it at the inner surface.

Unfortunately the register page of Optomarked.com doesn't work propperly at the moment, so I emailed them.

I will post whether this ends up in an improvement against the plane edtched glass lense.

I'm still convinced, that changing another tint will not solve the glaring problem sufficiently. The 'diffus-light' of test device_2 does the job very well, but to the expense of about 20...30% loss of overall luminous flux depending upon the "etchedness" of the lens.

Tobias


----------



## Barbarin

Tobias Bossert said:


> I just found a sherical diffuser (Khatod PLJT 35 and PLJT 35/02) which I will try to modify:
> 
> http://www.optomarket.com/jsp/index.jsp?p_gadgetURL=pagemapping.jsp%3Fid%3Dcatalog_illus&p_contentTopic=&pocs_bnav=yes&p_containerTopic=0000121203&p_Navigator=0000043212|0000043244|0000121203
> 
> It is just a hemisphere made from poly carbonate, outer diameter is 30.4mm and inner diameter is 24.4mm, so the material is 3mm thick.
> There are two types. One is extremely milky (PLJT 35) and the oher one (PLJT 35/02) they call "transparent". I will test both of them.
> The modification will be lathing (or sanding) it down to a hight of about 6..7mm remaining a spherical cap with an opening angle of about 90 deg, an inner diameter of 17..19mm and an outer diameter of 23..26mm.
> 
> I guess the milky type diffuses much to strong.
> In case the "transparent" one diffuses to weak, I will sand blast it at the inner surface.
> 
> Unfortunately the register page of Optomarked.com doesn't work propperly at the moment, so I emailed them.
> 
> I will post whether this ends up in an improvement against the plane edtched glass lense.
> 
> I'm still convinced, that changing another tint will not solve the glaring problem sufficiently. The 'diffus-light' of test device_2 does the job very well, but to the expense of about 20...30% loss of overall luminous flux depending upon the "etchedness" of the lens.
> 
> Tobias


 
Hi Tobias, 

A small exposure to cyanocrilate glue vapours is enough to "frost" slightly almost any transparent plastic. Faster than mill, and easier to test different exposure times.

Javier


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## Tobias Bossert

Barbarin said:


> Hi Tobias,
> 
> A small exposure to cyanocrilate glue vapours is enough to "frost" slightly almost any transparent plastic. Faster than mill, and easier to test different exposure times.
> 
> Javier


 
Hi Javier,
thanks, that's a good idea! 
I always tried to wrap with a solvent moisten cloth, but the result was very irregular, even when the cloth was nearely dry. I will play around with vapour, this is very easy to apply for freezing the inner side of a dome: just put a small drop of glue on a plane surface and place the dome over it.
Tobias


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## uk_caver

Frosting from cyanoacrylate does seem to be particularly likely if the dome has a tiny amount of grease from normal fingerprints on the inside.

It also seems possible to wipe the frosting off from at least *some* surfaces, just using a paper tissue.


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## gillestugan

Yes, I also have experience of "frost" that is quite easy to scrape it off, but as long as it is sitting on the inside it will be protected. 
Just a thought, but is it better to have it on the outside? Most frosted lenses are frosted on the outside and not the inside. Is there a reason?


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## likeguymontag

gillestugan said:


> Yes, I also have experience of "frost" that is quite easy to scrape it off, but as long as it is sitting on the inside it will be protected.
> Just a thought, but is it better to have it on the outside? Most frosted lenses are frosted on the outside and not the inside. Is there a reason?



I would recommend having the frosting on the inside. Caves are dirty, and a frosted lens would be very hard to clean. Perhaps there are additional considerations. Also, look into diffusing filters for photography or theater lighting. I would expect that you could get performance data for such products.


----------



## Barbarin

Off-Topic.

This is and extraodinary thread. I'm really happy with it because there is an active discussion about many facts related to portable lighting, reconsidering it from a starting point created one century ago.(carbide lamps)

There has been, there are and there will be billion threads about "tactical" and "notsotacticalbutgadgety" lights, basically handheld lights. But this one is being discussed from a perspective focused on real usage and real users which are not flashaholics, considering visual field, CRI, output, angle... Surprisingly no one has asked or insisted on the importance of a strobe setting (or five of them) and cavers are exposed to real dangerous situations. (IMHO it can be usefull, but not on every flashlight). 

Well, as I said an extraordinary thread on every sense of the word. Thanks for starting and following it.

Javier


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## uk_caver

gillestugan said:


> Yes, I also have experience of "frost" that is quite easy to scrape it off, but as long as it is sitting on the inside it will be protected.


The upside is that for experimentation, excess frosting may be reversible.



gillestugan said:


> Just a thought, but is it better to have it on the outside? Most frosted lenses are frosted on the outside and not the inside. Is there a reason?


I don't know enough optics to be be able to guess, but could there possibly be a small difference in light transmission for a given amount of frosting?
That is, if the outside surface is frosted, might some fraction of the light reflected back from the frosting into the lens be internally reflected off the inside of the lens and have a second chance at making it out through the front?

The intuitive feel is that optical setups should tend to be 'reversible', but that's maybe more appropriate to point-to-point systems (tracing light paths through lenses) than the kind of more random ('dirtier') point-to-spread setup involved in diffusers.


----------



## gillestugan

uk_caver said:


> That is, if the outside surface is frosted, might some fraction of the light reflected back from the frosting into the lens be internally reflected off the inside of the lens and have a second chance at making it out through the front?


That sounds likely.

I have been looking at the Ledil wide optics. They have this kind of tiny bubble texture on the top that works almost as good as a frosted diffuser in reducing glare, but with higher efficiency. I have ordered a pair for some testing. Will also test them on the MC-E as the larger die area tend to make the beam even wider. Using a MC-E is of course more expensive, but you can gain a lot in efficency from driving each die with 1/4 of the current.
I have also ordered a carclo 10403 which I will try to frost slightly.

Here is an overlay comparision of some wide lensens. Of course it doesn't tell the whole story, but it can give a hint. I would have liked to include the carclo 10170 reflector, but couldn't find a graph for it.


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## uk_caver

Is having a wider spread than a 'naked' LED (like the Carclo 10403) actually useful underground?

Typically, when moving roughly horizontally, a caver is looking along a passage, or across a floor.
Objects lit up by the centre of a flood beam are typically relatively far away - many times further away than the floor by the caver's feet, and possibly much further away than nearby walls.
Also, despite the fact that eyes can move, typically a caver will tend to turn their head if there's anyuthing of particular interest.
Peripheral vision, being more biased towards non-colour receptors can probably get away with less light than central vision needs.

Personally, I find a more centre-biased flood to be a more useful beamshape - having a little more throw, it has less need for supplementation with a spot beam, while still giving the benefits of a smooth flood.

I can see that there's a use for flat-flood optics like the Carclo 10403 for building lighting, giving a ceiling light with less of a hotspot underneath than a naked LED, but that's for applications where the LED is lighting a flat perpendicular wall, not lighting the inside of a tube or angled shallowly across a floor.


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## Tobias Bossert

I agree with with uk_caver: there should be as much light going to the center of the viewing area. Since no visible edge is comfortable, the spill should reach outside of the viewing area.
I like the pattern of XR-E very much, it is much more adopted to our needs than that of P4 - but I don't like its artefacts!

I have made some test in my cellar with some light distributions. First we start lightning a plane wall. The light is oriented rectangular to the wall giving a circular 'spot' on the wall. The following diagramm shows some pattern. The X-axis is the ratio of the distance from the spot center and the distance of the light source from the wall.
So '80%' means e.g. for a light that is 1m apart from the wall, that this point was measured 80cm away from the center of the spot.






'reflector' means Carclo wide angle reflector 10170. SSC P4 as well as Cree XR-E were measured as bare emitter, with the reflector pressed directly against the starboard and with the reflector clicked into an appropriate holder.
As you can see, the reflector does a very good job when used with P4 and its holder. Very good for architectural lightnings - not for caving, because we don't have a plane wall in front of us most time.
The reflector works well for us with XR-E increasing the flux inside of our viewing area. I took the combination without holder as a startpoint for my 'diffuse-light'. There is a sharp edge with this reflector - not good for using round the clock. But that's no problem, because we need a diffuser anyhow to reduce glaring.

The pattern given in the first diagram has no sense for walking in the cave. Therfore I calculated the spatial pattern out of it.






As a next step I used different diffusers with the combination XR-E and reflector direct. Until now I have made tests with plane diffusers only. They reduce glaring strongly, they do not reduce the 'beam' on-axis so strong and they nicely smoth out the edge. But with increasing off-axis angle the loss increases dramatically. Therefore I decided to study domed diffusers next. I'll come up with those results...

Regards
Tobias


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## gillestugan

Beautiful! 
Makes me want to delete my posted overlay as your post makes it look like child-play (which it really is in comparison). 
May I ask how you were able to create those diagrams?

I too don't think Carclo 10403 or a similar optics will be of any use. Im mostly curious. Was able to get free samples, so why not try them. They will probably be less than half as bright in the centre as a bare XP-E, and even less when diffused.

A flat-flood glare just as bad to the sides as to the front, so it is better to have more centre-biased for less problems with the glare. That is without a diffuser of course.


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## Tobias Bossert

*Revised diagrams in post #103 now*

In post #103 I explained the different scaling of X-axes of the diagrams but not the scaling of Y-axis and how I measured it.

I compared a SSC P4 USXOI with a Cree XR-E Q5 WC at 100mA. So the overall luminous flux may be different too, probably the XR-E delivers about 10% more than P4. Manufacturer specs state [email protected] for P4 U but [email protected] for XR-E Q5. So the ratio XR-to-P4 could have taken any value between 0.9 and 1.25 (luminous lottery). I’m not able to measure real overall luminous flux in my cellar.

I put the light source 50cm apart from a plane wall. I measured every 10cm from center of beam along the wall covering -60cm to +60cm. I allowed Excel to spline the curves. I did not normalize the values, it’s just the reading of my lux-meter.

I now have changed the vertical scaling of the diagrams in post #103:
All values are now normalized to “P4 center-value = 1,0”

I hope this clarifies the diagrams.

Regards
Tobias


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## Tobias Bossert

*Revised and translated comparison now!*

In post #84 I gave a link to Bucherls comparison of cave headlamps.
This was German.
Now we prepared an English version:

http://www.hirlatz.at/lampenvergleich_en.html

The explanations are extended now and a switchable comparison mode was added in 'detail 1'.

The original link to German page

http://www.hirlatz.at/lampenvergleich.html

still works and has the same extended explanations too.

Tobias


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## Tobias Bossert

*Testing diffusers*

Post #103 dealed with various combinations of LED-types and wide angle reflectors. I came to the result, that the combination XR-E and Carclo 10170 without holder (bond to the board directly) give the best distribution to start with tests of diffusers. 

The diagrams in this post here are normalized to the brightness of the bare emitter in the center (black curve). As in post #103 there are two different diagrams. 

The first one shows the normalized brightness of all the eight combinations tested on a plane wall. The light source was 50cm spaced from the wall. The distance along the wall is given as percentage of this spacing; 0% means on axis and 100% means 50cm away from the center (this equals 90 deg full width angle).





The second diagram shows the according angular pattern.





Both diagrams show the pattern of the bare XR-E without any optics (black curve as a reference). The pattern of the bare XR-E is very suitable for illumination of the whole viewing area - but a bare LED glares extremely.

For each of these eight curves i took a photo with identical camera setting. The camera was 125cm apart from the wall with wide angle optic. The bearer will never encounter such a situation, because the patterns cover a very wide angle. You can see the linear distance along the wall at the folding rule (hard to read at 800x800) and the full witdth angles on the yellow labels (30deg, 60deg and 90deg).

This photo is for bare emitter and belongs to the black curve 'bare emitter':





The 2nd curve (light blue) is the combination XR-E and Carclo 10170 without holder (reflector bond to the board directly) similar to that one described in post #103 but with a plane clear uncoated glass lens in front of it.

This photo is for XR-E with Carclo 1070 and glass lens and belongs to the light blue curve 'clear glass':





The flatness on a plane wall is nice, but not suitable for walking in a cave. The edge is much too sharp and artefacts are visible. And the glaring is the same as with bare emitter.

*Domed diffusers*

I tested a Khatod PLJT 35/02, which is nearely clear. I cut it down to a spherical cap with 6,5mm hight. the remaining diameter is about 24mm. This cap neither reduces the glaring nor improves the light distribution dramatically. I was astonished, that this dome provides some collimating effect and concentrates the brightness to the center!

This photo is for XR-E with Carclo 10170 and clear PLJT and belongs to the reddish long-dashed curve 'clear PLJT':





I made many experiments with PLJT 35/02 and vapor of different bonding agents (also cyanocrylat), but it was not possible to get a defined and homogeneous mat finish. I also tied to sand the internal surface - not good. The best result was achieved with a cleaner polish as used in the household. With this domed diffuser no glaring is left, the light source is about 300mm².

This photo is for XR-E with Carclo 1070 and clear PLJT and belongs to the reddish short-dashed curve 'sanded PLJT':





*Plane diffusers*

Next I tested three commercial and one home made plane diffusers.

First I tested XR-E with Carclo 1070 and L2optics OPTX-1-DIF8, which is a clip-on device for their 26mm optics. I bond it with the polished side onto a clear glass lense with epoxy to achieve a stable front lens. So the light enters at the rough side, quite the other way round than intended use. The glaring is reduced but still annoys, the light source appears 10mm² subjectively.

The photo belongs to the greenish long-dashed curve 'OPTX-1-DIF8':





Next I tested XR-E with Carclo 1070 and Ledil Ledilstar P SUB, which is a clip-on device for their 35mm optics. I bond it onto a clear glass lens as explained above. The glaring is reduced very well (30mm² subjectively).

The photo belongs to the greenish short-dashed curve 'Ledilstar P SUB':





Additionally I tested XR-E with Carclo 1070 and a diffuser not looking frosted but structured: OPTX-1-016S from L2optics. The glaring is reduced dramatically (200mm² subjectively) but the loss - especially at higher angles - is dramatical too! This belongs to the alternatingly dashed greenish curve 'OPTX-1-016S':





At the end I tested a selfmade diffuser: XR-E with Carclo 1070 and a plane glass lens etched at the internal side facing the LED. The glaring is nearely absent (200mm² subjectively) and the loss is acceptable. This belongs to the not-dashed blue curve 'etched glass':






*Conclusions*


A domed diffuser is much more difficult to produce and brings no real benefit as I thought before :-o
Some 'diffusers' concentrate light to the center too!
All diffusers I tested povide increasing losses at high off-axis angles.
It is possible to compensate the losses of a diffuser in the range of full beam angle up to 80 deg by using a wide angle reflector: This costs higher losses outside this range.
The angular pattern of a bare XR-E can be 'reconstructed' in the range -40 to +40 deg at a comparable level. But outside this range the 'reconstructed' pattern drops below that one of the bare emitter naturally. The etched plane glass is a cheap part for that.
I decided to use the combination XR-E with Carclo 1070 and a plane glass lens in front of it, etched at the internal side facing the LED. This will give a nice 'diffuse-light' when tilt down about 30 deg.


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## Tobias Bossert

For those who don't like to scroll so much, here is a picture containing all eight photos.


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## gillestugan

Thanks a lot. Those are great pictures and there is a lot of work you have done, and done very well. A bit disappointing the domed diffuser didn't work as well as hoped, but its good to know a cheap alternative works well. 
Losses from the diffuser seems to be a little more than 20%. Maybe this can be improved with a holographic diffusing film for example the LSD.
What are the numbers on the scales i the pictures? I will try to make a similar picture and plot for the Ledil SSS-W I am considering.
The Boom-W for SSC P7 also looks quite good with a beam pattern similar to a bare XR-E. But its probably better to use separate optics for the hall light.

Has anyone found a good cable gland? It would have been nice to have a good waterproof gland, but they all seem to be too bulky. Smallest I've found requires a 12mm hole for a 6mm cable.
I've previously used rubber grommets but they don't feel secure and have no strain relief.


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## likeguymontag

gillestugan said:


> I've previously used rubber grommets but they don't feel secure and have no strain relief.



For homemade strain relief, I've sometimes used several layers of heat-shrink. Heat shrink also changes the diameter of the cable in small increments, so you can experiment and get an extremely tight fit through your grommet. You can tightly attach a zip-tie around the cable on the inside face, and be fairly sure it won't pull through the grommet.

The Underwriter's knot is designed to address pull through, but probably wouldn't work well with the kind of cable I expect you're using.


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## Tobias Bossert

gillestugan said:


> Losses from the diffuser seems to be a little more than 20%.


Yes, you are right, 20% at least! Imagine that the wide angle reflector catches all light outside +/- 45 deg, that's a lot. Most of the light catched by the reflector is necessary to compensate the diffuser losses inside this angle, since bare emitter and emitter-reflector-diffuser combination just achieve comparable brightness inside of +/- 45 deg. 



> Maybe this can be improved with a holographic diffusing film for example the LSD.


This looks very interesting. Pleasy give some links where such a holographic diffusing film is discussed and where to order some samples.



> What are the numbers on the scales i the pictures?


There are two scales in the pictures.

The folding rule is scaled in cm and is centred with its reading "100" in the center of the beam. E.g., if you read "140" this means, this point at the wall is 40 cm out of the center of the beam; the same is true for a reading "60". Since the source was separated by 50 cm from the wall, readings of "50" and "150" are those points at the wall, were the distance at the wall from the center of the spot equals the separation between source and wall. In the first diagram these points are scaled as "-100%" or "100%".

The yellow paper labels above the folding rule mark the edges of beams with 30 deg, 60 deg and 90 deg full width. The yellow labels "90°" correspond to the reading at the edges of a beam with full width of 90 deg and thus both are 45 deg out of axis. The X-axis in the second diagram is scaled in "°" (=deg) off axis, that means, the yellow labels "90°" correspond to readings on the scale of the second diagram of "-45°" and "45°.

Readings "50" and "100" on the folding rule equal scale points "-100%" and "100%" in the first diagram and correspond to "90°" on the yellow labels, which are equal to the scale points "-45°" and "45°" in the second diagram.



> Has anyone found a good cable gland?


I'm not experienced in building water- and bombproof housings, this is a task for manufacturers commercially producing headlamps. My mission is to improve the light distribution of headlamps only.


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## Tobias Bossert

*Now the aspect of glare*

In post #107 I posted the test results with respect to the achieved light distribution. That is what you will see when you bear the helmetlamp. This post now deals with what your friends will see, when you look to them - quite different point of view!

In post #107 I also gave a rough subjective estimation of glaring. This was done with the light source 1m apart from my eyes and the eyes beeing in the center of the beam. The XR-E Q5 WC was driven with 100mA.

In this post I'll try now to document the amount of glaring with photos. That's a difficult task, because the dynamic range of photos is limited.

The result leads me to assume that the subjective sensation of glare is not "linear". Anyway, the subjective glare and the "measured" brightness and extension of the light source don't comply directly.

I mounted the LED with its axis tilt downwards by 30 deg and shot the photos from horizontally in front of it. This simulates the situation when you talk to another person face by face. The camera settings for the photos in post #107 were f=1:8, t=1s @ ISO100. The current to the LED was 100mA and the spacing between LED and white wall was 50cm. For these tests here, the settings were f=1:22, t=1/1000s @ 100ISO.

Even with the camera turned down in this manner it was necessary to reduce the LED-current to 10mA. Nevertheless the pictures are overdriven at the most bright parts. On the other hand, the dark parts are drowned out.

Here is a picture with the photos of all 8 combination tested. The layout of the photo corresponds to that one in post #108:





As I stated at the beginning, the subjective sensation of glaring doesn't compare directly to the photos - but you can see how the diffusers work.

The photo "clear-glass" is a good excample to demonstrate dynamic range of photo and eye: I had no problem to see the reflector in total, althoug the die glared me. on the photo you can see the lower part of the reflector only, that is the area wich is active in the upper beam direction.


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## gillestugan

I was not able to make the measurements on the Ledil SSS-W with the photo resistor and ohm meter as I hoped. It was too inaccurate, maybe I will try again later in combination with a diffuser over the resistor.
Post some beamshots instead. Emitter is a XR-E 50cm from wall. 





The Ledil optics have very high efficiency and doesn't glare much at all, but Im not sure I want to trade 20 degrees more narrow optics for 15% higher output.



Tobias Bossert said:


> I decided to use the combination XR-E with Carclo 1070 and a plane glass lens in front of it, etched at the internal side facing the LED.


I get significantly higher losses from my etched glass when I place the etched side on the inside (towards the emitter) than on the outside. 
The LSD seems (too) expensive, $80 for a 10x10cm sheet. Samples can be requested here.


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## Tobias Bossert

gillestugan said:


> The Ledil optics have very high efficiency and doesn't glare much at all, but Im not sure I want to trade 20 degrees more narrow optics for 15% higher output.


 
Definitly I would not accept further 20 deg reduction of beam angle for 'diffus-light' even when this would result in about 15% increased efficiency.
The Scurion uses room light with about 160 deg - too wide for the person bearing the helmet lamp. I reduced it to about 90 deg, tht's the absolut minimum, which could be accepted only when the edge is very smooth. 



> I get significantly higher losses from my etched glass when I place the etched side on the inside (towards the emitter) than on the outside.


 
The lamp will be used in caves and there is a lot of loam. With the rough surface out you may get problems with loam, since it is difficult to clean it only by hand. Therefore I excluded 'rough side out' up to now.

Visually I didn't experienced this heavy difference. But I will make some relative measurements and post the results soon...

What will be tested? Not all possible combinations, since some exclude from other reasons.

With etched, sanded or sandblasted glass lense I can turn them to matt side out without any problem.





Cheep plastic diffusers like OPTX or LEDILSTAR are thin and not solid enough for a cave lamp. So I need to cover them by an additional glass lens (or a thick polycarbonate lens). The problem with this is, that I get 4 surfaces with backscatter instead of 2.





I avoided 2 of these backscattering surfaces by bonding the polished surface of the plastic diffuser directly onto the inner side of the glass lens. This works fine, because the refractive index of epoxy is similar to those of glass, polycarbonate and acryl.





It is not possible to bond the rough side of the diffuser to the glass lens, because the epoxy will fill it up and the diffusion disappears.

I'm interested how big the difference is objectively?



> The LSD seems (too) expensive, $80 for a 10x10cm sheet. Samples can be requested here.


 
Yes, much too expensive for you and me. And at the end - if I can find a manufacturer using our findings and ideas - it will not be used because of price. So I must accept the losses of 20 to 25%.


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## gillestugan

Beautiful drawings, but I feel a bit guilty. I didn't mean to give you more work. Just was a little bit surprised when I got more than 5% lower output when I turned the frosted side in (measured with a photoresistor). 5% is hard to notice, but it means you can lower the power consumption of the leds by at least the same %.
The frosted glass I use is a quite heavy frosted photo filter.

The first idea is often the best, and this search for lenses and diffusers are a good example. but.. Im still hoping for another solution as I would like a more simple method. It is a lot of work to get a frosted lens in the right dimension, then mount it to the reflector and then make it securely mounted to the headlamp at an angle.


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## Tobias Bossert

*Here is a comparison of rough surface inside and outside*


I tested the thre "winners" of the last test:

etched plain glass lens
OPTX-1-016S
LEDILSTAR P SUB
In all diagrams there is a grey curve for bare emitter XR-E, which was measured with a plane glass lense (uncoated clear glass), since in caves we can't use the bare emitter without protection. This glass lens takes some % of light (4 to 6%).

All tests were carried out with the combination XR-E / Carclo 10170 without holder and in front of this either the etched glass or a combination of commercial diffuser and clear glass lens as explained below.

The etched glass is compared with etched surface inside (facing the LED) and with surface looking outside:





This is the result with the etched glass lens:





As you can see, no one orientation is really better than the other, but the effects are different: With the "usual" orientation "etching outside" the brightness in the center is about 12% higher, but with "etching inside" the beam gets considerably wider.

With both commercial diffusers the effect is comparable. They were tested in combination with a plane glass lens:





This is the result for OPTIX-1-016S, which is not frosted but has a rectangular texture:





This is the result for LEDILSTAR P SUB, which is rough-frosted:





The subjectiv glare is uninfluenced from the orientation of the diffuser.

At the end I can verify the general rule to use "diffuse side out". But especially if you want to get a very wide smooth pattern, the opposit works better.


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## Tobias Bossert

*Using 1 or 4 dies of MC-E with a Carclo 10195*

As you remember, my "testdevice_2" had four independant LEDs. I announced trying to reduce the device to three LEDs without loss of functionality.
I was not sure on this, because I didn't know the result of useng one die of MC-E only in a TIR. Now I'm sure, the approach of a 3-LED-Lamp will work!
I made some photos from that. The optic was 50cm apart from the wall. the yellow labels mark a full beam width of 30deg (+/-15deg). As usual, those photos don't show what you will imagin subjectivly, because the eye has a quite different dynamic as a photo.

XR-E Q5 WC @100mA with Carclo 10195 (20mm medium frosted) and Holder 10205 





MC-E K WC all four dies @25mA each with Carclo 10195 and Holder 10512 




As you can see, the beam is broader with MC-E than with XR-E (may be full beam witdh is about 10deg wider) and the pattern tends slightly to a rhombus. The LED was mounted diagonal so that one die is on top, one on bottom and two side by side horizontally. But there is no artefact and no donut - esthonishing since Carclo 1095 was developed originally for Rebel, quite the opposit, a small emitter!

MC-E K WC only the uppermost die @100mA with Carclo 10195 and Holder 10512 




As you can see, the center of the beam is declined downwards by about 10deg now ans seems to be slightly higher than broad. But it is still smooth without edges and rings.
This could be used to light-up a diffuse light smoothly without anoying edges.

In the following picture I mounted both photos of MC-E beams together. On the left side the uppermost die is driven allown and on the right side al four are used.





*Conclusion for my project*


I can use the combination of Cree MC-E / Carclo 10195/10512 to integrate the strong 'hall-light' (2.8A) with the week 'light-up' (30mA) without the need for a driver-dynamic of 100:1.

For my 'work-light' I want a superposition of 'light-up' and 'diffuse-light' diverging by about 30deg. Since the tested combination with only one die is displaced by about 10°, the champfer in the casing for the diffuse-light can be reduced to about 20deg.

Thus the 'testdevice_3' should look like this...




...in theory, but I'm not professional manufacturer and my hand made result will look more improvised!


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## gillestugan

Here comes my test of diffusers. (at last)
The meter was connected to the led with a string som distance to led was constant. I also measured light level every 5 degrees, so I ended up with 200 measurements... PM me if you want the numbers.

The diffusers were placed tested 7mm in front of the bare emitter. When using the carclo 10170 80 degree reflector it was placed direclty in front of the reflector.

The lenses and diffusers used were:

KD multicoated 1,5mmX50mm lens
KD Sodaglass 1mmX26mm lens
LSD 5 degrees (light shaping diffuser) from POC
LSD 30 degrees (light shaping diffuser) from POC
LSD 80 degrees (light shaping diffuser) from POC
Fastcar 5L diffuser (unknown manufacturer)
Fastcar 10L diffuser (unknown manufacturer)
Frosted Glass (Rowi international photo filter)

XR-E emitter, Linear scale






Carclo 10170 on XR-E, Linear scale






XR-E emitter, logarithmic scale






Carclo 10170 on XR-E, logarithmic scale






Now, it is in the area around 40 degrees it gets interesting. 
Notice for example how the Fastcar 5L has the same brightness as the frosted glass at angles between 40 and 50 degrees, while at the same time having 15% higher brightness in lower angles. Not bad at all.






I also have taken some photos for evaluating anti-glare performance. Unfortunately I was not satisfied with the fastcar diffusers and it seems frosted glass is still a good solution as the LSD:s are horribly expensive.







And Tobias, good it worked fine with the single-die carclo 10195 setup. Thanks for testing. 
I tried it with the 10194 and it looked really bad. Going to use that setup too. Looks good and makes for less components than driving all the dies at low level.


Edit:
Some more information:
I placed rough side towards the emitter on all diffusers.

The fastcar 10L was not as effective as frosted glass for reducing glare. Better than LSD5, but the "grain" is quite large. I would estimate the frosted glass is 50% better. It is still much better than a bare emitter/reflector, so if someone wants to trade some glare for better output it may be a good alternative.
It is 0,3mm thick, and quite though, it would probably hold for a while if placed in front of a 20mm reflector. Not bombproof, but i think it would work.


I took new close-up pictures to show grain size.


----------



## Tobias Bossert

Hi Anders,
very good work and very informative posting!

Could you add the secondary grid to the logarithmic diagrams (not only 1, 10, 100 but also 2, 3, 4, 5, 6, 7, 8 and 9) please, this would be better to compare bare emitter to emitter&carclo. Just replace the uploaded diagramms...

I like your results of 'Carclo - Fastcar 10L' since this combination seem to reduce glare and has losses lower than the frosted glass you tested. What is the subjective effect of glare suppression of this combination, does it match to frosted glass? 

Which orientation of diffuser did you use during test, rough side in or out?

Your findings are corresponding with my results: A diffuser reducing glare sufficiently will reduce the 'gain' of the Carclo reflector 10170 to about zero, that means you just can achieve the pattern of the bare emitter within a beam of +/-40° and pay for glare suppression with losses outside this angle.


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## gillestugan

Thanks. I have added the grid to the diagrams, good suggestion, I was a bit tired yesterday when I posted them and didn't think about it. 
Also added some more information at the end.

I still think a 20 degree LSD would have been great, but the cost is way to high to justify. 

I am still working on the single pole rotary switch circuit based on the AX2002 drivers. Have some problems with diodes and will post eagle schematics when solved.


----------



## Tobias Bossert

Hi
I'm back again. Now I finished the 3-LED-testdevice.

Pause-Light
XR-E WD R2 and Carclo 10170 and internally etched glass lens @50mA

Work-Light
Diffus-part: Same XR-E WD R2 and Carclo 10170 and internally etched glass lens @150mA(low)/250mA(high)
plus
Light-up: One die of MC-E WD M and Carclo 10195 and clear glass lens @30mA(low)/125mA(high)

Hall-Light
All four dies of same MC-E WD M and Carclo 10195 and clear glass lens @4x750mA

Shaft-Light
XR-E WC R2 and aspherical glass lens 21,5mm dia x 20mm fl @1150mA

In the lab it works similar to the former 4-LED-testdevice.

We will test it at the weekend 8/9 August in Hirlatzhöhle - I will post some results, shure.

If this new test device holds what it promisses in laboratory, I'm finished developing a reasonable headlamp for big caves. In this case I will post circuit diagram, layout and mechanical specifications, so everyone can build such a lamp by its own. It's rather for self made man than for commercial manufacturer. But may be there will be some manufacturer taking the ideas and developing a commercial device from it - would be very interesting!

We started a poll on our caving club website to find out the wishes and requirements of cavers with respect to helmet lamps.
http://www.hirlatz.at/umfrage/fragebogen_en.html
The more cavers participate, the better the data basis to develop new improved headlamps.

Regards Tobias


----------



## morow

*Edit for readability - sorry it was in paragraphs when I hit submit I promise!* 
I am working on designing a dedicated caving headlight as well. Right now I am looking at using 2 Endor Rebel stars with 3 emitters on each. 

Flood - I plan to use one star with a very wide angle reflector and either frosted glass or some other diffusing coating/film. I want a wide even spread. probably about 150 degree. A fairly strong diffusion would be necessary using any small reflector with these due to the widely spread emitters. 

Throw - The second star I hope to test the available 20 degree colmenating lens. This will be more for lighting up wide passages then a narrow beam to spot deep pits. Until I test it or see a review I am concerned about the throw pattern, and efficiency. I doubt it is much over 85% efficient and could be worse. For controls I am planning a 4 position switch. 

1. off 
2. Flood only - set at about 35 lumen or less. This is my resting or break time setting. I don't need any distance lighting, and am very concerned about glaring my companions. We will often be facing each other or consulting a map or such. 
3. flood and Throw in parallel - set around 150 lumen. This setting will be my most used for moving about the cave. I hope the combination of flood and fairly wide throw beam will give good coverage for all needs. 
4. Flood and Throw in parallel- set around 600 lumen. For large rooms and distant targets. This setting would be used only in short bursts. Taking into considerations losses in the optics I shouldn't need more then 1A of drive current to hit my #4 setting target. I could do this with a single externally dimming driver using multipole multithrow switch(s) and resisters. 

I don't often get the chance to do very deep pits, so a narrow beam is of little use to me. The farthest I need to project is typically 300 feet at the most and often well under 200 feet. 

Concerns and thoughts. 

I wonder if 2 additional settings would be handy. 1. A setting between #2 and #3 above for close in work. Something around 70 lumen for small passages. Probably a combination of Throw and Flood. 2. A stronger distance setting dedicating the full 1A of current to the Throw. Of course if I only intend setting #4 to light up the big rooms the flood may not have much effect at all. I could just drive the Throw in setting #4 and be done with it. 
I plan on mounting the batteries to the back of my helmet. I am looking at LiFePo batteries for a compromise in safety, energy density, and voltage. Running the batteries at 1/2C for only short bursts and at 1/8th C for extended times I think I can safely shrink wrap then rubberize the battery packs for safety and water resistance.


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## TorchBoy

_Pleeease_ use paragraphs, morow.


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## morow

O, I like your idea of the down angle light for close in work and lighting up the area infront of your feet without having to swivil the entire headpiece. It would be nice to have a usable light without the need for an hinge to move it up and down. Less complex and it would probably be easier to keep the weight close to your head and limit how far out the light extends.

In my use I normally swivel up/down my light when I need to look at something close. I don't think I often need to swivel the headlight to spot a distant object. So a flood pattern like you have works for looking forward and down.


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## TorchBoy

Wow, morow. So much more readable. I like the different LEDs (and optics) for different uses approach, and I'm slowly working on something like that myself. I take it that you and Tobias don't find that frosted/etched glass cuts down the intensity too much?

Tobias, I've just filled in your survey. Thanks for an English version!


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## Tobias Bossert

Hi all,
last weekend we took some photos in Hirlatzhoehle to compare the new Testdevice_3 using a 3-LED aproach with the old Testdevice_2, which used 4-LED approach.
You can see this at http://www.hirlatz.at under 'New comparison'.

There is still the 'Old comparison' too, but we changed the layout a little bit: Now its on a dark background, because the photos are dark too.

As you all know now, I'm not expert in machine-made bombproof cases. But I'm glad I that got what I got - handmade without machines!





My fingers are for demonstrating the size of the device





The dimensions of the case (without knob and cable-feedthrough) are 86mm x 56mm x 24mm. The wight together with 1m cable and connector is 140g.

The real-world-test in the cave resulted in some minor modifications to be done - thats the reason why it takes one week to come up with this posting.

The changes at the cirquitry are done now, so I can post the circuit diagram and description for everyones free use:
http://www.bossert-inet.de/tobias/Circuitry_Testdevice3.pdf

The layout of the small motherboard will be changed too, so I'm posting it later.

The case is a Hammond 1591 XXM, which I deformed termally with a selfmade molding press. I will have to change this molding press too, because I got problems with sealing the lenses.

It is prooven now, that we can combine the Hall-Light and the light-up part of the Work-Light. When you compare the beamshots of 'Old testdevice 2' with 'New testdevice 3' you will see, that the old Hall-Light was a little bit better. But any Hall-Light is luxury anyhow, so I optimized the compromise towards a good light-up of Work-Light.

Work-Light has two levels: low and high. Distance to forground doesn't change much with room size, therefore the diffuse part of Worklight is increased by 66% (150mA to 250mA) only from low to high. But distance to background changes strongly, thus the light-up part of Work-Light is increased by 300% (30mA to 125mA). 

Some cavers accompanying our photo session last weekend think, that it would be sufficiant to have Pause-Light, Work-Light low and high and Hall-Light. They proposed to leave away Shaft-Light completely.

If so, the lamp would be reduced to 2 LED only.

But I myself like to have a narrow thrower. This is not new idea of me, since I hand-made my first "Halogeny" in *1978*, as you can see here:




Fully regulated at that time!





One caver proposed to switch to a TIR instead of the px glass lens. O.K. this will result in a higher lumen output, because all light not reaching the px lens is waste, that's true. TIR like Carclo 10199 (or 10048, the maximum size I could use in this small case) provide soft edges and a litle bit of spill, so you will recognize the surrounding too. He thinks, this would be better. But personally I think:

If the shaft is narrow, than any spill will annoy you
If the shaft is wide, than why not using the Hall-Light?

As you can see, it's unpossible to satisfy everyone: That's life!


Next to do?
I will correct the motherboard and the molding press and than 'produce' about ten samples. 

Why? 
These ten devices will go to active cavers at cost price and without guarantee. I hope these cavers work as multiplicators. If so, than more and more cavers will demand such optimized light distribution - and at the end some professional manufacturer will produce commercially machined helmetlamps providing good pattern.

All parts together cost about 150€ at the moment, cost of labor would be much much higher, because all is handmade.

I hope you enjoy the beam comparisons, they are much more meaningfull than beamshots onto a white wall.

Regards Tobias


----------



## Tobias Bossert

*All clear*

Now it works. 

The reason for this confusion was:
We developed the site and tested it with Firefox 3.5.2 only. It worked correctly. Than I gave the link in post #126.
Only some hours later we got the information that some text in the tables is black and some tables ar much broader than the frame when usin MS IE8. Oh MS!
Than we looked for a work around under time pressure. Gottfried found it - but with these multible cut and past he copied the wrong table.
Now it works fine - and we know, that we got the better browser with Firefox...


*Attention*

We got some confusion in the table for Scurion P4 at the 'New comparison'
The pictures are not the right order at the moment.

I will give the all clear when we have solved the problem.
Hope it will be soon...

Tobias


----------



## patudo

Hi from Spain :

I haved read your post very slowly(my english is not good) but i understanded every each word. The planification is espectacular and i hope you will arrive to the perfect cavinglight. Here in Valencia (Spain) i am working with standart leds(seoul p4) regulation cards and Li Ion batts 18650. I wont emulate the carbide light i am looking for a new kind of light, but it is hard. 

Notice that, never the light movement has got this trubble since its creation by Edison. It's a new light world into our cave world. We are pioneer and selfcontructers, that is the esence of the right caving people.

Nice to talk you i hope i can help you in the future, and cave togheter.

Carlos Vergara Speleological Society La Senyera. www.espeleosister.com


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## TorchBoy

Tobias Bossert said:


> All parts together cost about 150€ at the moment, cost of labor would be much much higher, because all is handmade.


:thinking: I'm struggling to figure out where that cost has gone to. Would you care to elaborate?

Edit: I'm reminded of John Harrison, who went on inventing marine chronometers until he came up with a design that could be manufactured comparatively inexpensively.


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## Tobias Bossert

TorchBoy said:


> :thinking: I'm struggling to figure out where that cost has gone to. Would you care to elaborate?



Hi TorchBoy
if you are a prifessional than you are allowed to struggle:
I calculated all costs on base of enduser ordering one part only from each type and having to pay tax (in Germany 19%) and postage.

The most costy part is the rotary switch 6x2 with IP68: about 30 Euro
Next is MC-E WD M with about 25 Euro
Two XR-E WD R2 together about 15 Euro
Motherboard about 12 Euro
Glass lens about 8 Euro

The sum of only these six parts is even 90 Euro!

In case a manufacturer starts a serial production, these parts will be much cheaper at quantities of hundreds. For me the total sum of all parts are just below 150 Euro; I guess a manufacturer can get them all for half this price.

But remember please: 
I definitly do not plan to produce this lamp commercially - so the costs don't matter for me. I'm happy being able to demonstrate that light distribution can be improved dramatically.


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## Tobias Bossert

Tobias Bossert said:


> One caver proposed to switch to a TIR instead of the px glass lens. O.K. this will result in a higher lumen output, because all light not reaching the px lens is waste, that's true. TIR like Carclo 10199 (or 10048, the maximum size I could use in this small case) provide soft edges and a litle bit of spill, so you will recognize the surrounding too. He thinks, this would be better.



O.K., let's look what we can do...

I gathered some "narrow beam" optics and build a device to compare them under real world conditions. Here it is:




That's no well designed model, it's simply a device to make some comparative tests.

The optics are as follows:


Spherical pcx glass lens 21mm (Anchor Optics AX77183), 20cm diam. at 1m (11°), scharp edge, rel. center brightness 100% (referenz, this is the lens of testdevice_3)
Aspherical pcx acrylic lens 24mm (DX sku:4614), 30cm diam. at 1m (17°), scharp edge, rel. center brightness 52%
Aspherical pcx glass lens 28mm (DX sku:5297), 49cm diam. at 1m (27°), scharp edge, rel. center brightness 29%
TIR 20mm plain thight (Carclo 10199), subjective ~35cm diam. at 1m Entfernung (18° subj.; 8° spec.), rel. center brightness 82%
TIR 20mm frosted narrow (Carclo 10200), subjektiv ~26cm diam. at 1m (15° subj.; 10° spec.), rel. center brightness 59%
TIR 26mm clear (L2 OPTX1006), subjective ~20cm and ~40cm diam. at 1m (11° / 22° subj.; 20° spec.), rel. peak brightness 103%
TIR 26mm diffused (L2? Ledtech LT-1452), subjective ~30cm diam. at 1m (17° subj.; 16° spec.), rel. peak brightness 82%
TIR 26mm plain thight (Carclo 10048), subjective ~28cm diam. at 1m (16° subj.; 6° spec.), rel. peak brightness 117% (points) and 71% (middled)
TIR 26mm frosted narrow (Carclo 10124), subjective ~28cm diam. at 1m (16° subj.; 11° spec.), rel. center brightness 81%

Here you can see comparative beam shots from these 9 optics.





The device doesn't look so nice, because all those optics were fixed with silicone. There is a severe reason for this:

I first tried to use the original holders as intended. But it worked very bad.
This was a new finding for me, since in past I always used the original holders to center the optics. But in past I always used frosted or rippled wide or at least medium - and whith those broad angled beams adjustment doesn't count so mutch.

So I had to adjust every optic manually. I modified all holders to allow adjustment of at least 0.5mm in every direction. This helped dramatically.

As an example I show you Carclo 10199/10425 without modification (above) and with manual adjustment (below):









In this case the x/y-centering of LED and optic was already o.k. but the size of die images from TIR and from center lens was different. Therefore an adjustment in z-direction was necessary by about 0.6mm, that means I had to get the LED out of the optic by about 0.6mm, to acieve maching sizes of both images. This smothed the beam pattern but increased the spot fom about 10° to about 18°.

Result: Carclo 10199 may be optimized for lambartian sources but gets problems with the primary lens of Cree XR-E.

In principle, such corrections were necessary with all six TIR I used. Sometimes also adjustment in x/y-directions were neccessary too.

I realized adjustment by putting the holders into a bed of silicone on the starboard. As you can see, with some optics I didn't found an optimum adjustment. Additionally the adjustment somewhat disappeared during drying.

At the end I came to the conclusion:

You can use the original holders with medium or wide beam
You'll have to adjust the optic manually for narror beams

With pure lens no such problems arise.

Now this device with 9 optics is on the way to be tested in Hirlatzhoehle, I'm interested which one will be testers first choise...


----------



## Tim

Hello Tobias,

First i would like to felicitate all members in the forum that have participate activily in this thread.
I am triyng to devolope a headlamp but using just 2 LED. and my perference go to MC-E Warm white.
In the devolop 3 i do have some questions...
Where do you put all the drives, with such a small box?
Why dont you use just one drives and use mosfet as switch is less space and power lose in driver.
I would like to help you in the electronics part if you want, need!
I will include in my project a power meter with 5 LED to see how much power remains in the battery and a PWM for power control the drives with a microcontroller.

Tim


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## bordali123

Hello,
there is another lamp on market with much lower cost than Scurion. 
http://www.spelemat.com/ledlampe/
Maybe you could make some comments.


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## Tobias Bossert

bordali123 said:


> Hello,
> there is another lamp on market with much lower cost than Scurion.
> http://www.spelemat.com/ledlampe/
> Maybe you could make some comments.



Hi Bordali123,
this lamp is new for me. There are not enough technical specifications on the web site, so I can't say anything about its features.


It has a modified standard case, making it cheaper for small series.
The user interface seems to be similar to that of Scurion.
The 'room light' is not as wide as Scurion - this should result in less power consumtion during worklight (may be similar to my testdevices).
The thrower looks similar to that of new Scurion K, I don't know the beam pattern at the moment.
As with Scurion you can combine flood and throw - but I don't know how good both sources will complemet each other (this isn't optimized with Scurion).
Both beams are concentric and thus there will be no effect 'light in the foregroud and light in the background' at same time without realizing a two-beam-pattern all time.

At the moment I know nobody who owns this lamp, therefore it's unpossible for me to make meaningfull comments on it.

We have to wait untill this lamp is tested by somebody...

Regards
Tobias


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## Tobias Bossert

Tim said:


> I am triyng to devolope a headlamp but using just 2 LED.



Hi Tim,
as some testers in our club claim too, two LED would be sufficient and the shaft thrower ist not necessary. So you may be on the right way with your two LED project.



> my perference go to MC-E Warm white.



I know many cavers prefering warm white instead of cool white (there is normal white in between). But this doesn't realy make any technical difference, since you can decide which color bin you put into work at the end of producing the sample - all other parts are totally independent of this decision.




> Where do you put all the drives, with such a small box?



Please wait for some weeks, I'm developing a complete set of documentation of testdevice_3 at the moment in parallel with building ten samples of it. In this documentation you will see how I managed it to put 5 driverboards, my mainboard and all three optics inside this small box...




> Why dont you use just one drives and use mosfet as switch is less space and power lose in driver.



Because it's easier for me to use five complete driverboards than to develop one universal type and switch (and split) its output to several LEDs. But you are completely right: This method is unuseable for a professional manufacturer producing high counts of devices.

Thank you also for offering help. At the moment I definitly do not plan the become professional manufacturer and for my small count of samples, I found a practical way to realize it.



> I will include in my project a power meter with 5 LED to see how much power remains in the battery and a PWM for power control the drives with a microcontroller.



This will work with lithium rechargeables only...

Regards
Tobias


----------



## Tobias Bossert

Tobias Bossert said:


> Now this device with 9 optics is on the way to be tested in Hirlatzhoehle, I'm interested which one will be testers first choise...



And now it's back again. 

The testers say that with a strong and not too wide Hall-Light indeed a Shaft-Thrower is unnecessary. But Hall-Light of 'testdevice_3' is additionally used as light-up for Work-Light and therefore needs to be wide enough (I took a frosted medium with more than 25° FWHM). This is optimum for combination with the diffuse part of Work-Light and good as Hall-Light too but too wide and too much spill for looking into deep pits.

The testers disliked the Shaft-Thrower of my original 'testdevice_3' because it is too narrow (10° FW). That was the reason I gave them the device with 9 different throwers to test.

Result:

All lense optics and 'plain tight' TIR are better than the 'frosted' ones, because frosted optics produce to much spill far apart from the center of the spot
Other than I predicted, the beam should not be narrow but more like medium (15 to 20° FW instead of 5 to 10° as I thought)
The thrower should provide a reasonably flat pattern inside the beam and than fall down at the edge rapidly but not with too strong edge on the other side

They say, the beam shots I posted have no direct correlation to the subjective sensation when used in real cave. The sensation much more depends upon the spill and the pattern outside the 'half maximum angle', which you can't see on those beam shots.

The first choice was #4, Carclo 10199 20mm optic plain tight for XR-E, displaced mechanically to align both images (from internal lens and from internal reflector).
Estonishing... not the same as I thougt looking to the white wall in my cellar!

I will follow this finding and replace the lens by that TIR for the 10 samples I'm producing now.


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## Tobias Bossert

Tim said:


> I would like to help you in the electronics part if you want, need!



Hi Tim,
I'm producing 10 samples of modified testdevice_3 at the moment. This takes me much time, because I'm preparing in parallel complete documentation of the whole lamp. One part of that documentation is existing at the moment but naturally is still preleminary. I give you the actual version; please realize that this may change until publication!
http://www.bossert-inet.de/tobias/Circuitry_of_Helmetlamp.pdf

In this document you will find other links to the board layout too.

The circuitry uses either Kennan_II (PT4105) or Kennan_II (AX2002), but for my application with dimmed output the old PT4105 is much better, as you can see here:

http://www.bossert-inet.de/tobias/PT4105_vs_AX2002.pdf

I still had left 17 Kennan_II and 3 Kennan_I, so I can produce all 10 samples with PT4105 boards. But afterwards these are gone! Since PT4105 is discontinued and I dislike AX2002 for that application, I will need an alternative.

You offered to help me with my electronics and proposed to use one converter only and distribute the currents to the LEDs via MOSFETs.

Do you know a DC/DC converter delivering an output voltage of 3.5 to 4V suitable for an output current range from 50mA to 2.5A? Minimum current is during Pause-Light, maximum is for Hall-Light.

All circuitries I know so far provide poor efficiency when loaded with 2% of max current only!

Regards Tobias


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## TorchBoy

Tobias Bossert said:


> The testers disliked the Shaft-Thrower of my original 'testdevice_3' because it is too narrow (10° FW).


That's interesting. I use a 5° aspherical lens-focused beam for shaft throwing because I've found 8-10° from a TIR optic is too wide to have really good throw. Maybe we mean different things by "shaft thrower"; I doubt our shafts are bigger. Maybe they weren't actually using it for shaft throwing.


----------



## Tobias Bossert

TorchBoy said:


> That's interesting. I use a 5° aspherical lens-focused beam for shaft throwing because I've found 8-10° from a TIR optic is too wide to have really good throw. Maybe we mean different things by "shaft thrower"; I doubt our shafts are bigger. Maybe they weren't actually using it for shaft throwing.



I'm with you completely. That was the reason I used aspherical lens with testdevices 1, 2 and 3. Starting nearely focused so that the rectangular structure of the die was just gone (about 5°). Than after some criticism of the testers I defocused it so that there was just no increased intensity at the edge (about 8°).

I think you are right, they didn't used it for really narrow deep shafts during testing indeed! It seems they tested it rather in big halls with infinitly high ceiling or in very large canyons, which you can find more oftenly in Hirlatzcave than narrow shafts.

O.k., that will be up to the manufacturers to decide whether to implement a thrower at all and of which type if so. The most important thing of my work is the combination of flood and soft throw to a usefull worklight. I would be happy if some manufacturer would adopt this strategy, independently whether he adds a thrower or not.


----------



## uk_caver

I'm just wondering how efficient the aspherics are at capturing light from the LEDs - does much light miss the lens?


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## Tobias Bossert

uk_caver said:


> I'm just wondering how efficient the aspherics are at capturing light from the LEDs - does much light miss the lens?



It depends...

Especially XR-E is good for use with aspheric lens with respect to caching a high portion of the emitted light, because it has its own internal lens narrowing its initial beam to below 90° FWHM. Some PCX asheric lenses with a usefull diameter of e.g. 21mm have a back focal length of below 7mm. So really a very small portion of light is missing the lens. 

Nevertheless, with a good TIR you achieve higher efficiency but to the costs of more spill and not such a uniform beam.


----------



## Tobias Bossert

There was a longer pause now ...
but not for doing nothing!

I added temerature control and overdischarge protection to 'testdevice 3' in the mean time. To get this all into the very smal casing I modified the circuitry: The rather big rotary switch able to carry the supply current must go and I replaced it by a tiny one for low level signals only. Also the mechanical arrangment had to be modified. 
The result is below.





The AA cell is for size reference only.

The light distribution of this 'device_3a' is exactly the same as with 'testdevice_3' discussed at last in this thread - the optics are just indentical.

I handcrafted 10 samples of this headlamp for the cavers in our Austrian and German caving clubs.
Here you can see, which versions were produced: http://www.bossert-inet.de/tobias/three_variants.pdf
and here you find the very detailed manual for it:http://www.bossert-inet.de/tobias/usermanual.pdf
The samples were delivered in spring of this year - and must be recalled immediately after that, because of thermal problems. That's all corrected now and these devices are used now continuously under real caving conditions.
From this experience I learned, that a good headlamp needs an aluminium casing for cooling - not ABS as mine with an aluminium lid on the back side only.

I had contact to some European manufacturers of headlamps. Most of them told me, that the market for cave specific headlamps is too small to start such a rather complex development. For very low numbers of pieces it is not economical to use a proprietory casing developed for this device only. 

One manufacturer asked me, whether I could modify the optical arrangement of the light sources to allow a standard rectangular aluminium casing. If so, he will develop the electronics and all other things needed and will offer such cave-proof headlamps commercially at a much lower price than common. Naturally with modern programmable digital switching, because rotary switches are too expensive and tend to be not really watertight.

That's it, what I'm developing at the moment ...
... and it seems to be feasible!

The fist prototypes achieve nearely the same light distribution as 'testdevice_3' - but all front windows lie in one plane, allowing a standard rectangular casing:




This demontration sample has no electronics inside, it has a six-pole cable so each led can be driven externally. As you can imagin by those scratches, it even was tested inside a cave. For this purpose I developed a (not so compact) box with electronic inside: No problem for demonstrating feasibility only.

Now I hope that this progression satisfies the needs of the manufacturers and one of them starts to develop an inexpensive headlamp optimized for huge caves on this basis.


----------



## Barbarin

Hello Tobias, 

I could point you in the right direction...


Javier


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## Tobias Bossert

We made new comparisons in Hirlatz Cave (Austria)
3rd Comparison
4thd Comparison

This time we compared the light output of 10 different headlamps:
LedLampe IV
Scurion P7 (discontinued)
Scurion 1300
Petzl DUO LED 14
Petzl ULTRA
Petzl ULTRA WIDE (comming soon)
Device 3a (shown two posts above)
Prototypes 1 to 3 (model 2 shown above)

If maximum achievable output counts, there are three favorites delivering roughly about the same light output (1300 lumens): LedLampe IV, Scurion 1300, Prototype 3.
The first one is quite cheap, the second one is quite expensive and the third one is just a laboratory model only.

If optimum light pattern counts, Device 3a and Prototypes 2 & 3 outperform all others - but they are not achievable on the market. 
LedLampe IV has the best flexible superposition of narrow and wide beam parts of all headlamps on the market and additionally uses diffusers to avoid glaring. But it has no real thrower (narrow spot).
Scurion 1300 is improved with respect to older Scurions, but still both patterns do not supplemet each other reasonably. In our opinion it makes no sense to superpose both, because the FWHM of both parts are too different.
Petzl ULTRA WIDE is much better than Petzl ULTRA for walking in caves, but provides one pattern only - neither narrow thrower nor really wide diffuse light. This headlamp has six LEDs but uses them allways in parallel, just as one common light source.

Here is a short description of those Prototypes:





This device has only two independent light sources like LedLampe IV and all Scurion models. On the right is a XP-G with wide angle reflector, optical deviation and diffuser giving FWHM >90° (from 75° downwards to 15° upwards). On the left is a XP-G with a ripple medium TIR with deviation giving FWHM 28° (from 4° downwards to 24° upwards). Hall light is about 350 lumens. There is no shaft thrower.





This device has three independent light sources like Device 3a. The wide diffuse beam on the right is identical to that of Prototyp 1. Also the medium beam on the left is similar to Prototype 1 but with FWHM 32° (from 6° downwards to 26° upwards). Hall light is about 450 lumens. The thrower for shaft light uses XP-E and 20mm TIR with FWHM 8° at 250 lumens.





This device has three independent light sources like Device 3a. The wide diffuse beam on the right is identical to that of Prototyps 1 and 2. The medium beam on the left uses three XP-G, deviation and diffuser giving FWHM 28° (from 4° downwards to 24° upwards). Hall light is about 1300 lumens. The thrower for shaft light uses XP-G and 26mm TIR with FWHM 8° at 450 lumens.


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## gheza1976

Hi Tobias,

You are doing a great job on this reasearch! I read this thread from begining til end and backwards. I started my own project in building a helmet lamp based on leds firstly for me, then if I stabilise the prototype for my buddys from our caving club. 
I managed to buld the electronics at least in test phase. Now i-m working on the electrical and mecanical part of the project. I use a standard aluminium enclosure box: http://esales.eldon.com/IDS/ArticleData.asp?ArticleID=HALP061004GE&ProductID=4545 . It's rated IP65 but I think i can make it more whater tight. Further I have some questions on this part...
1. Can you point me some rotary switches that you used. Especialy i am intrested in low power ones with at least IP66 protection rate. The IP68 would be the best. I searched the internet and i dont find any relevant results. I think rotary switches or rotary encoders are esential for this project in making the lamp easy to use in caving contitions when ur hands are mosly covered with dirty gloves. I tell you about the rotary encoders because I managed to program some simple pic microcontrollers (PIC12F683) in order to do the digital switching feature and you can use this encoders or push buttons as input. 
2. Regarding battery box my first option would be the petzl duo's. You can order it separatly i didnt asked for price yet. Do you have other options?

Thanks in advance,

Geza.


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## Tobias Bossert

gheza1976 said:


> ... I use a standard aluminium enclosure box: http://esales.eldon.com/IDS/ArticleData.asp?ArticleID=HALP061004GE&ProductID=4545 . It's rated IP65 but I think i can make it more whater tight. Further I have some questions on this part...



I used Hammond 1550 WP http://www.hammondmfg.com/1550W.htm which is IP66 with standard gasket and upgradable to IP68 with a separate gasket.



> 1. Can you point me some rotary switches that you used. Especialy i am intrested in low power ones with at least IP66 protection rate. The IP68 would be the best. I searched the internet and i dont find any relevant results. I think rotary switches or rotary encoders are esential for this project in making the lamp easy to use in caving contitions when ur hands are mosly covered with dirty gloves. I tell you about the rotary encoders because I managed to program some simple pic microcontrollers (PIC12F683) in order to do the digital switching feature and you can use this encoders or push buttons as input.



I used Marquardt 9037, which is IP66, not upgradable. 

The Swiss manufacturer TechTonique http://www.spelemat.com/ledlampe/ has developed a new "LedLampe V", which is a improved commercial version of my prototype 3. This headlamp will be availlable in August 2011. Comparable to "LedLampe IV" this modell is controlled by a toggle switch (moment - off - moment) and is IP68.



> 2. Regarding battery box my first option would be the petzl duo's. You can order it separatly i didnt asked for price yet. Do you have other options?



I myself and most of my fiends use a NiMH battery for model flights 4,8V 3,7Ah wrapped in heatshrinking sleve http://www.conrad.de/ce/de/product/206019/NIMH-48V-EMPFAeNGER-AKKUPACK-3700MAH and worn in the chest pocket of the overall. TechTonique offers the yellow Petzl Duo battery case, but the contacts of this box are not so good I think and four AA cells are not strong enough to support up to 17W. For LiIon I know no usefull box (you can't buy the box of Scurion separately); TechTonique offers the Battery packs of Petzl Ultra at a special rate.


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## gheza1976

Thank you for the quick replay and the useful information about the casing, switches and battery.



Tobias Bossert said:


> The Swiss manufacturer TechTonique http://www.spelemat.com/ledlampe/ has developed a new "LedLampe V", which is a improved commercial version of my prototype 3. This headlamp will be availlable in August 2011. Comparable to "LedLampe IV" this modell is controlled by a toggle switch (moment - off - moment) and is IP68.


 
Thats a great news! For that price and with functionality developed by you i think it will be the best choice to buy. 
Electronics and caving are my hobbys so self made devices have more like a spiritual value. Thats why i will continue the development.
I'm anxious to see the new LedLampe model and maybe test it too. I hope they will provide soon the long pomised opensource code for programming the microprocessor of the lamp.


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## gheza1976

Any news on Ledlampe V which will be manufactured based on your prototype 3? On their site is stil not available.


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## Tobias Bossert

gheza1976 said:


> Any news on Ledlampe V which will be manufactured based on your prototype 3? On their site is stil not available.



There is a note at the bottom of the French homepage of the manufacturer:

"Pour info
Afin de répondre efficacement à la demande croissante et parvenir à réduire les délais de livraison, une nouvelle structure de production est en création. Basée en Valais/Suisse, elle sera opérationnelle courant septembre 2011. C'est également là que sera produite la nouvelle LedLampe V. D’ici là, nous vous remercions d'ores et déjà de votre indulgence !"

Neither on the English nor on the German page are comparable notes.

Translation:

"For information
Our new production plant is under construction in Valais / Switzerland. We hope we could satisfy an increasing request efficiently and reduce delivery time in future. The facility will start up some time in September 2011. Than we will sart production of new LedLampe V. In the mean time we apologize for any inconvenience!"

There seem some delay setting up the new production plant, it is end of November now.

A friend called them for ordering a lamp and was told that the delivery will start in January now.

I'm very interested to get a first sample of LedLampe V in my hands for testing.

Tobias


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