# Portable LED desk lamp



## Erasmus (Jun 1, 2008)

Hi there!

These days I'm studying very hard for the upcoming exams (the next 3 weeks). I sometimes love to study during the night, especially when it's very hot during the day. Then the temperatures are better during the night, it's very silent, yet very dark. A few days ago I was playing with a Maglite and started to think about making a portable LED desk lamp to take with me while studying in the garden during the night. 2 hours later a new baby was born, shining bright in the darkness  

Portable LED desk lamp : 

portable : take it anywhere and it will stand on every flat surface
flexible : the locline stalk is flexible so you can aim the light in any direction you want
based on 2 Maglite 2D flashlights
featuring 4 Cree XR-E warm white LEDs, high efficiency and nice warm white color
2 switches on the head : one to switch on/off and another to switch between low and high mode
running on 9 AA batteries, preferably NiMH but alkalines work fine as well
high-efficiency driver circuit with constant current output of 380 mA to each LED
custom heatsink to improve heat dissipation from the LEDs
glass lens
2 modes : high (4 LEDs) and low (2 LEDs) 
brightness : estimated 360 lumen on high, 180 lumen on low
long runtime : full output for 4* hours (high mode) or 8* hour (low mode), many more hours of decreased output (* = based on 2000 mAh NiMH AA) 

Now some pictures! All pictures are clickable to see the full size image.


The portable LED desk lamp : 








Comparison of beamshots (note : all shots were taken at the same manual setting on the digital camera) : 





I actually never planned this project. It popped up in my mind and I started working on it. Barely 2 hours later it was ready and I went studying outside with it. Overall I'm very satisfied with this lamp. Color rendering is very good, long runtimes and a surprisingly high light output. I used Cree XR-E warm white P4-bin (color temperature 3000-3200 K) and I might consider to do another group buy on these since warm white LEDs open a whole new world of LED projects!

Please feel free to share your thoughts and other ideas for more projects with warm white LEDs  

Thanks!
Erasmus


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## darkzero (Jun 1, 2008)

Very very cool! I absolutely love the creativity! Nice job! :twothumbs


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## LukeA (Jun 1, 2008)

I am also in love with the WW Crees.


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## Erasmus (Jun 1, 2008)

Here are some more pictures to make things more clear:




Edited the beamshot picture to make the brightness difference clear : 








Edited some more to compare the high output mode to the 35W halogen lamp : 




The total input power is the power that is drawn from the energy source, not the power going to the light. So all driver inefficacies are included in the ratings.


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## ambientmind (Jun 1, 2008)

very cool light! where did you get the warm white crees? i need to get some.


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## McGizmo (Jun 2, 2008)

Cool build! :thumbsup: I like the base.


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## jch79 (Jun 2, 2008)

:twothumbs Cool! 

Nice innovative thinking there, Erasmus!

john


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## Erasmus (Jun 7, 2008)

Thanks for the nice comments, really appreciate it  I've been through several charges now and some severe testing of the locline (to see whether the wires will break during extensive bending), testing of waterproofness (looks like raining season over here) and testing during any practical use it can be used for. So far it's proved to be an amazingly handy (flood)flashlight!


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## LukeA (Jun 7, 2008)

ambientmind said:


> very cool light! where did you get the warm white crees? i need to get some.



Cutter has them.


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## Erasmus (Jun 7, 2008)

ambientmind said:


> very cool light! where did you get the warm white crees? i need to get some.


I got some of these for a group buy a time ago (January) but sold everything to a project of a fellow CPF'er. I'm planning to do a new group buy, end of June maybe.


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## J.McDonald Knives (Jun 7, 2008)

Looks great man. You thought about making a wider base for it so it doesn't get knocked over easily and make it more stable on uneven surfaces? Also I want one!!!!


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## 1 what (Jun 7, 2008)

+1 for the Base!:twothumbs.
I can remember studying and finding all sorts of things that I simply had to do first but in your case you actually did something worthwhile...not sure that's permitted. Good luck with the exams.


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## Erasmus (Jun 7, 2008)

J.McDonald Knives said:


> Looks great man. You thought about making a wider base for it so it doesn't get knocked over easily and make it more stable on uneven surfaces? Also I want one!!!!


Yes I thought about this, the design will be improved after my exams, I'm even considering building 10 of these lights for CPF members, if there's interest.

Improvements make it possible to attach the flashlight either to a tripod or to a custom made base to improve the stability.


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## J.McDonald Knives (Jun 7, 2008)

Just an idea, Next one you make you could use a 3 cell D and then cut off enough to make base for 2 batteries and use the rest for the lamp head. Save you a little money and would make it nicer looking IMHO. Just my $0.02.


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## Illum (Jun 7, 2008)

Where can I find such "loclines"?


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## darkzero (Jun 7, 2008)

Illum_the_nation said:


> Where can I find such "loclines"?


 
http://modularhose.com/llworld.htm

The Shoppe also has some too:

http://theledguy.chainreactionweb.com/index.php?cPath=90&osCsid=0864f44c226915aed2776fa60d524750


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## LED_Thrift (Jun 7, 2008)

Great idea. Students are sure smart these days. I like the two switch idea also.


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## Erasmus (Jun 7, 2008)

J.McDonald Knives said:


> Just an idea, Next one you make you could use a 3 cell D and then cut off enough to make base for 2 batteries and use the rest for the lamp head. Save you a little money and would make it nicer looking IMHO. Just my $0.02.


Thanks for the good idea  I'll consider it for the next, although I like this one more because the head gives a lot of stability on flat surfaces, even without an extra base.


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## Erasmus (Jun 7, 2008)

LED_Thrift said:


> Great idea. Students are sure smart these days. I like the two switch idea also.


Thanks  The dual switch system is really handy, can save you some runtime when you need it while remaining a very decent light output.


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## J.McDonald Knives (Jun 7, 2008)

Erasmus said:


> Thanks for the good idea  I'll consider it for the next, although I like this one more because the head gives a lot of stability on flat surfaces, even without an extra base.



You could also make a wider base that looks like m*g lite head. Make it almost like a no-spill coffee mug if you know what I mean.


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## Erasmus (Jun 8, 2008)

J.McDonald Knives said:


> You could also make a wider base that looks like m*g lite head. Make it almost like a no-spill coffee mug if you know what I mean.


Hmm interesting idea, but how to make a good waterproof construction of this? I think it's difficult to build this.


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## Jarl (Jun 8, 2008)

Love the design!! I'd love a desk lamp like that, but mags are ridiculously expensive in the UK


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## J.McDonald Knives (Jun 8, 2008)

Erasmus said:


> Hmm interesting idea, but how to make a good waterproof construction of this? I think it's difficult to build this.



Use O rings like are on the tail cap.


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