DIY DENTAL HEADLIGHT PROJECT

Daneland

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Hello Guys and gals.
I will try to explain my DIY project on this thread. I am a dentist (my wife is a dentist too and she is the one wants to have the light on her loupes) who hates to be ripped off :scowl: and refusing to pay £300 (at least) for a 3w LED, an aluminium case and a battery pack.I have no electronic knowledge and skills but I am good at finding solutions (at least thats what I think:grin2::grin2:).
I have looked for DIY project or a simple conversion of a decent torch in to a LED headlight but I cant find a completed guide including this forum. All I can find here is half way projects and ideas.
I initially bought a cheap dental LED headlight from e-bay. It was claiming it was that it was a 3W LED but it was not. However it gave me a chance to try different optics I harvested from different cheap torches and jeweler loupes. Even the LED is not powerful enough, I managed to get a bright focus but this was not really homogeneous and there was some considerable spill around it. I thought, if I could have changed the LED with 3W power LED, possibly I could have had a better light. So, I have decided to find a decent torch to harvest parts and try to assemble them. I have purchased a couple of LED Lenser TTs( they have not arrived yet).I am hoping to get a bright and homogeneous light in the end. I am planning to use an aluminum round shape apertura (made from iphone's back cover, widely available, cheap or even free) to let the light shine through a small hole to create a small area. If TT's flood light is powerful enough on short distance, I am hopping w/o any more adjustment I will get something good enough. If not I will try to create improve it's focus light with some other optics.
If you dont mind me asking I have some basic question.The dental loupe I purchased has a battery unit. I opened it up and they are a couple of AA size batteries connected with a small electronic unit which makes possible to adjust the light intensity.Do you think I can use this pack to power up TT's LED(TT originally uses 3 X AAA battery) ?Will the potentiometer ( I guess this is the name of the part of the device to adjust brightness) work on TT's LED.a

As soon as I have TTs I will send pictures of the project. Please do not forget when commenting , I am not very knowledgeable about LEDs, electronics and optics:mecry::thinking: and dont get frustrated with me please :banghead:
 

DrafterDan

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Hi DL,
Yes, that's what we call "Asian manufacture Lumens", meaning there is no real international standard on lumen output. Each manufacturer can set their own yardstick. So when they say a 3" light fed by a AAA battery can put out over 1,000 lumens, take it with a grain of salt. The good thing is that manufacturers that give a damn put a lot of their reputation, so when they say it has xxx lumens, they feel confident it will be at that range or better.

I looked up those Lenser TT's, I don't know much about the driver in them, but they do make pretty solid products. I think it's a good idea for a first-round trial.
On the battery, the TT is originally fed by 3x AAA, or 4.5 volts. Two AA cells would be 3 volts, so you are already running a deficit. You might consider a single 18650 Lithium Ion cell, which fully charged is 4.2 volts, but runs at a nominal 3.7volts. It would also give way more runtime than alkaline AAA cells.

What body are you thinking about using for the LED's?
 

Daneland

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Hello DD
I have had my TT yesterday.It is a beautiful piece of kit. I've tried the lenses I had, unfortunately I can get a nice round sharply defined round focal spot the size I want.But I can get a very well defined LED shape bright enough w/o much spill around it. To be honest with you there are small dark dots on the LED shape light but they are so small and they are impossible to notice on the working distance I will use. All I had to do, adding an LED lens I harvested from a cheap torch in to the screwed front housing of the TT's original front bit (I guess there is a name for this part but dont know) As soon as I learn how to add photos, I will send its pictures. I compared the light with a very expensive (https://www.orascoptic.com/products/headlights/endeavour-2 ) dental LED headlight and it is not any brighter than TT.
If I can find a single lens to get same result it will be a lot easier. Depending on the lens(es) I will use, either I will use 22m copper plumber pipe or cheap dental headlight I bought from the ebay but it is sort of plastic and cooling might be problem.Second challenge will be sorting out the battery. I need a battery can give 4 hours min with constant current.

A quick question, is the front surface of the LED going to get too hot after 1 hour usage? I am asking it because with two lenses set up the cheap lens get too close to LED
 

Daneland

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This is the sharpest and most homogenous spot I can get. It is not round but it is very bright and there is very little spill. Today I removed the lens and managed to get a similar spot with a single lens. I might need to find a better quality lens ( the one I use is a cheap acrylic lens) Anyway I can definitely think it will work for mw. I now need to remove LED and managed to find it to transplant in to a suitable housing.As I am busy with many other things, it progresses slowly.Today, I attempted to remove the LED but so far I have only managed to cut the part that holds the lens ( the part you slide to adjust the zoom) I hate to cut the aliminum and it realy pissed me off.But still cant remove the part holding the LED> I will take some more pictures next week and send them, maybe you can enlighten me how to disassemble the body of TT.



 

The_Driver

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I hope you have thought this through thoroughly...
No offense, but I wouldn't go to a dentist who uses homemade apparatuses of any kind.
 

Daneland

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I hope you have thought this through thoroughly...
No offense, but I wouldn't go to a dentist who uses homemade apparatuses of any kind.

Actually it is offensive.But you are entitled to your opinion and I do not care what you think.
 

The_Driver

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I said that because as a patient I of course always have an opinion of my doctors and it can be influenced by many differenct aspects of their treatment. I don't want you to lose patients because you wanted to save a buck on a light. ;)

Here are some tips anyway:
As a doctor I would only use high-cri LEDs, basically full-spectrum light sources. These render colors correctly like the sun, incandescent bulbs or proffesional grade medical lights allowing you to accurately see things. I would probably use a 5700K LED (closest to daylight) or maybe 5000K. This number tells you the color temperature of the light source.
The Nichia 219C LED with 90CRI and 5000K or 5700K is a good candidate. It can be bought here. It requires a pcb for mounting (here) and a driver (electronics, depends on what batteries you want to use).

How much runtime do you need a what brightness each day? Are you willing to charge the batteries every day?
 
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HarryN

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Learning about LEDs, drivers, and optics can be a lot of fun. Building your own lights (no matter how well they work in the end) is a great learning experience.

Dental lights are one of the most challenging, from an optical viewpoint, IMHO. The reason is that the quality of light, (smoothness, brightness, color quality) have to be very high within the lit area, but essentially be at "zero" outside of the desired area.

The things that you would do optically to achieve a highly focused, efficient beam, also tend to downgrade other required qualities. In other words, don't worry too much about efficiency and concentrate on the beam quality because the two are sort of opposites.
 

HarryN

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Small aperture hole in a piece of metal
- Conceptually, this seems like it should work well, but it works sort of mediocre
- If the light source is close to the hole, then light which is diverging tends to pass through and diverge
- If the light source is very far away, then a lot of light is lost by reflection off the sheet metal barrier
- In spite of what might seem obvious, the edges of a hole in a sheet will still act somewhat like a lens, and give odd edge effects to the final beam shape.

I guess the message is - don't be surprised by these effects - they are normal.
 

HarryN

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Sorry for making these short posts - for some reason if I try to type longer posts, something goes wrong and the content gets lost.

As far as taking things apart, most likely you will need a heat gun to soften the adhesives. Optical assemblies need to be aligned fairly carefully to work well, and usually simple mechanical alignment is not sufficient for high end lights. Professional optical assembly builders use laser pointers, multiple holders, and optical glue to build things up. It is a pain in the neck to do mechanically, but with a laser pointer - fairly easy. Just hang the laser pointer from the ceiling pointing down and let nature do it's thing.
 

HarryN

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Your beam photos are very useful for a discussion on beam shaping.

The fact that the beam is square ish is often associated with a TIR type optic. It could also be a 2 stage reflector + lens but it is a classical TIR type output and those are much lower cost than a 2 stage optical system. I have built lights using both methods and it takes someone exceptionally interested in flashlights to bother with 2 stage optics, and I mean above and beyond normal flashlight forum members.

There are a couple of EU companies that specialize in TIR optical components and they are very good quality, easy and inexpensive to purchase. (as in a few dollars) True 2 stage optics are going to sell for at least 20X that much.

The other thing that makes me think that the beam is from a TIR optic is that the face of the LED is being projected on to the wall in one of the photos. This is the downside of TIR optical systems as the beam really is what the LED face is. Sometimes you can reduce this effect by light sanding of the front of the optic, or slightly defocusing.
 

Daneland

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I said that because as a patient I of course always have an opinion of my doctors and it can be influenced by many differenct aspects of their treatment. I don't want you to lose patients because you wanted to save a buck on a light. ;)

Here are some tips anyway:
As a doctor I would only use high-cri LEDs, basically full-spectrum light sources. These render colors correctly like the sun, incandescent bulbs or proffesional grade medical lights allowing you to accurately see things. I would probably use a 5700K LED (closest to daylight) or maybe 5000K. This number tells you the color temperature of the light source.
The Nichia 219C LED with 90CRI and 5000K or 5700K is a good candidate. It can be bought here. It requires a pcb for mounting (here) and a driver (electronics, depends on what batteries you want to use).

How much runtime do you need a what brightness each day? Are you willing to charge the batteries every day?

Hi ,thank you taking time and contributing.

I will make sure that the light will not look like a hideous piece of DIY equipment. I can use the casing I bought it does look quite good actually.

Related to your comment about the certain colour temperature and rendering, I am not so sure that it is that important. There are a couple of good reasons for it: Firstly, a common dental light uses halogen bulb @ 3200 with CRI 100 but new LED dental lights are a lot more complex and they are around 4000-6000 K ( https://www.kavo.com/en-uk/dental-practice-equipment/kavolux-540-led-operating-lights and http://docs.wixstatic.com/ugd/9a4afd_e5d922ba73fe4fb288b98dc1633ca410.pdf ) and funny enough well know dental headlight are significantly different than this values (https://www.orascoptic.com/products/headlights/endeavour-2 ) So ,it shows that many different colour temperature could be good enough.
Secondly, main light source is the dental light not the loupes headlight, inevitably hands and instrument block the dental light and a secondary light is quite handy to illuminate obscured areas. Light is significantly important when taking the shade but if I am making a restoration requires a good colour match I will never ever use my loupes headlight, room light or any artificial light source. Simply I ask my patient to see my lab and they can take the shade.

I do not think that I will use it more than a couple of hours daily, I will use them when I use my loupes and I dont think that I will need them on all times.

What I try to do ,which seems more complicated than the beginning; to harvest different parts from reasonably priced equipment and assemble them. If I can get the rectangular spot shown on the photos after I put the LED and lens in to the ebay headlight, my mission will be fulfilled. But I guess it will be the first step for exploring more complicated solutions.

Learning about LEDs, drivers, and optics can be a lot of fun. Building your own lights (no matter how well they work in the end) is a great learning experience.

Dental lights are one of the most challenging, from an optical viewpoint, IMHO. The reason is that the quality of light, (smoothness, brightness, color quality) have to be very high within the lit area, but essentially be at "zero" outside of the desired area.

The things that you would do optically to achieve a highly focused, efficient beam, also tend to downgrade other required qualities. In other words, don't worry too much about efficiency and concentrate on the beam quality because the two are sort of opposites.

Yes, I do agree with you, I have always enjoyed to build/produce things. It is a very satisfying feeling.

Your beam photos are very useful for a discussion on beam shaping.

The fact that the beam is square ish is often associated with a TIR type optic. It could also be a 2 stage reflector + lens but it is a classical TIR type output and those are much lower cost than a 2 stage optical system. I have built lights using both methods and it takes someone exceptionally interested in flashlights to bother with 2 stage optics, and I mean above and beyond normal flashlight forum members.

There are a couple of EU companies that specialize in TIR optical components and they are very good quality, easy and inexpensive to purchase. (as in a few dollars) True 2 stage optics are going to sell for at least 20X that much.

The other thing that makes me think that the beam is from a TIR optic is that the face of the LED is being projected on to the wall in one of the photos. This is the downside of TIR optical systems as the beam really is what the LED face is. Sometimes you can reduce this effect by light sanding of the front of the optic, or slightly defocusing.

TT's LED fac is pretty smooth and there are only tiny tinny dots on it and with high intensity due to short distance they are near to impossible to notice.But if project on to a surface far away compared my ideal distance , they become more noticeable.

As soon as I remove the LED and its driver from TT, I will test them and see how it goes. I have a feeling that I will need some good advice on this point.

Many thanks for all your contribution
 
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The_Driver

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Indeed, it's a bit weird that only the first of the linked lights seems to have a high light quality.

Another way of choosing a suitable LED would be to just try to match your other illumination sources. The color temperature should be the same.

What are you using?

BTW: the LED I linked to has a very high light quality, is reasonably bright, has a good efficiency and is not expensive.
 

newmind

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Jan 31, 2018
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Hi. I too am a dentist. I am just a novice at this DIY project and so I am looking for some advice.
Dental manufacturers are charging extortionate amounts for these LED lights. I've been quoted nearly £1000. And considering I spent so much money on courses, other dental equipments etc, I would like to save some money.
Keep us updated.
I will soon start my own project too.
And regarding what The_Driver said, we are just trying to make an additional light to see things better. We won't be using this in the patient's mouth. Seriously it's no big of a deal. We are not trying to make our own DIY dental drills, xray equipment , etc
 

Daneland

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Do not think that I have given up. I am too busy and as soon as I have time I will work on it and keep you guys updated
 

vmaldia

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I gave advice to a friend of mine who is an ENT doctor. As an ENT doctor he always looks down narrow deep holes, even more so than a dentist so the light must ideally be right between the eyes. We looked around aliexpress and I advised him to get something like this

... hotlinked image removed ...

But the mount looked more like this, just ignore the eyglasses and the loupe. It was just the light, the battery, the wire and the mount.

... hotlinked image removed ...

He mounted it on what looks like the headband from a contruction worker's helmet.

... hotlinked image removed ...

He said he was quite happy with it.

My other friend is a cardiovascular surgeon. He has the real thing, bought in the USA during a medical convention. And except for the fact that it came with eyeglasses and loupes and the mount was a little shorter, it looks almost identical if you ignore the brand names printed on the battery. Although I have not seen both headlamps side by side the intensity of the light of the cheap chinese copy looks only a little weaker than the original one.
 
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