# LED light from scrap and left over pieces .....



## wquiles (May 4, 2014)

I have this Dewalt 18V incandescent "lamp" what plugs into the Dewalt batter pack this model, in case anyone wants to buy one for a similar project.  I trade it/barter for it many years ago, and it has been sitting in a shelf in my home office - just sitting there, as I hoped to eventually do something with it.  I like it since with the heavy battery base, it can stand on its own, and have the head pivot at either horizontal or vertical, which might come handy.


I wanted to take it camping with my son's scout pack on March, but I ran into some trouble, and I could not finish on time.  This weekend I finished it 


I measured the threads on the head as best as I could - something like 18TPI:






I started with a scrap piece of Aluminum - gummy, does not machine well (certainly not 6061), but it was "free", so I used it as a base for this project:










To give the new head/heatsink a non-slip surface, I gave it a swirl knurling finish:






Then face, and bore for the thread side:










Then cut the threads, and test fit:










Cut the "excess" in my revamped bandsaw:






After machining the oposite side for the LED and the lens pocket, the head was finished.  Here it is compared to the original plastic retainer ring:










For the LED head/heatsink, I decided on color quality over quantity, so I used several LED's with a high CRI value, which I had in my storage for 3-4 years:






and in the middle, I used on the McGizmo high CRI LED's he sold years ago:












Not pretty, but this is how I decided to plug the head/headsink to the swiveling base:






Now, since these packs charge to higher than 18V (actually in the 21V range), I decided to use one of my own PWM LED controllers, connected in direct drive (for high efficiency), and to make it adapt to the temperature in the head - so as it warms up (new/fresh batter), the PWM duty cycle gets smaller (which lowers the temperature), and once the temperature lowers, it can go back to the initial, higher duty cycle.  Of course I have a 5C histeresys in the software, so that this is all very gradual, and automatic (Tiny85 gets calibrated at programming time).  Of course, I can't connect a 3V PWM signal without some sort of switch, so again, I am using one of my own small MOSFET boards as the switching element.  Here is the setup in my bench - I have a "sticky" thermal pad between the boards and the metal head, and epoxy to keep them in place (that schematic is the one for the "white" PWM controller board I designed):






Bench testing.  The back of the my controller board has the Tiny AVE programming pins, so that I can re-program/fine-tune as part of the development of the firmware settings - right now I am letting the head get to about 48-50C before picking a lower PWM duty cycle:






Here is the initial duty cycle setting - about about 68-69% (yes, I am under-driving everything, for cooler temps, and longer runtimes):






Once the temperature level is "hit" the PWM adjustment takes place, lowering the RMS current, thus starting the "cooling" process for the LED's - here the duty cycle is 50% lower than initial, at about 34%:










Finished product:









I just simply used the original plastic lens, and glued it down in place using epoxy:





Up and running (pun intended!):






Not too bad for stuff/pieces I have laying around, right?


----------



## hvontres (May 4, 2014)

Love your home test equipment setup


----------



## wquiles (May 5, 2014)

hvontres said:


> Love your home test equipment setup



Thanks - it certainly makes things easier to debug. Most everything bought over the last 10 years or so, a lot from Ebay :hi:


----------



## wquiles (May 9, 2014)

I reprogrammed the controller to offer 3x output levels, and low battery detection/shutdown.  Two short videos here:
[video=youtube_share;YPrAtgEb_s0]http://youtu.be/YPrAtgEb_s0[/video]

[video=youtube_share;u7VIDBekM4w]http://youtu.be/u7VIDBekM4w[/video]

Will


----------



## Marco Bernardini (May 10, 2014)

Now a great improvement would be to make a pivot for the four external LEDs, to have a "tele-wide" option…


----------



## wquiles (May 11, 2014)

Marco Bernardini said:


> Now a great improvement would be to make a pivot for the four external LEDs, to have a "tele-wide" option…



Just a "little" outside of my knowledge/capabilities )

But seriously, the multi-level was the best mod for this light.  Now it can be "dialed-in" for the task at hand, and thus have a much longer runtime.


----------



## brino (May 11, 2014)

William, colour me impressed. You absolutely "own" both the mechanical and electrical realms of this.

There's no doubt in my mind that you could a LED swivel or beam focus if you cared to.

Thanks for the great post with lots of pictures and lots of details.
It is very appreciated.

Keep turning scrap into great tools!

brino


----------



## Marco Bernardini (May 11, 2014)

wquiles said:


> Just a "little" outside of my knowledge/capabilities )



Here is my 0.02 euro solution:




The main LED is placed on a central screw.
The secondary LEDs are on pivoting plates with a small spring (those of dead Bic lighters are good) on the external side, pushing up.
When the central screw is moved outside, it pushes the pivoting plates, and the secondary LEDs point outward.
The central screw must of course have a very fine thread, 1 mm/turn or so, since LEDs are very directional.
What do you think?


----------



## wquiles (May 11, 2014)

Marco Bernardini said:


> Here is my 0.02 euro solution:
> 
> (snip pic)
> 
> ...



Looks great.  The only challenge I see is the thermal path for the LED's - without a solid, good thermal path to the heatsink, the LED's will cook themselves and die in a very short time.  If you can figure out that, then it would be a good working solution 

- - - Updated - - -

Now, to have something with good throw, I came up with another retrofit.....

I also have this very heavy duty 26650 host I bought 2-3 years ago, which I had dissembled to change its driver (did not like the modes, levels, etc. - typically low cost AMC7135-based driver).  The light itself is great, with outstanding thermal path, etc., but it sat there in parts in my "shop" for several years:














Well, this LED PWM controller and FET switch worked so well in the DeWalt, that I decided to try to retrofit the same solution in this host.  I started by flattening both sides of the brass heatsink/driver cavity:










Instead of some random XM-L, I found these I bought 3-4 years ago for some other project:






I had to reflow SMT parts to make two more FET switches:








I then epoxied together the the LED PWM controller board and FET board (same boards I used in the DeWalt - just changed the SMW resistors to adjust the battery range in the analog input of the Tiny85):










Then used Kapton tape to isolate the botton board (FET switch) from the heatsink to prevent a short circuit:












Then epoxied the two boards into the brass heatsink:






Finished product:






The exposed pins allow re-programming:






Unfortunately the phone camera auto-adjusts, but you can sorta-see the 3 levels (always starts in low level):
















Of course, this has a deep reflector, so it has very good throw, so now I have a floody and throwy LED work light combo - all with parts I had for several years just laying around the shop 


Will


----------



## Marco Bernardini (May 11, 2014)

wquiles said:


> Looks great.  The only challenge I see is the thermal path for the LED's - without a solid, good thermal path to the heatsink, the LED's will cook themselves and die in a very short time.  If you can figure out that, then it would be a good working solution



Uhm… a whole pivoting heatsink? Perhaps with a lot of holes into it, for venting?


----------



## wquiles (May 11, 2014)

Marco Bernardini said:


> Uhm… a whole pivoting heatsink? Perhaps with a lot of holes into it, for venting?


Yup, that would work better.  Heat-wise, the LED's work like the CPU in a computer - it gets hot, and needs a heatsink to help disipate the heat - otherwise the temperature increases until the chip dies.  But unlike a CPU heatsink, there is no fan in a portable light, so you rely on having a large surface to spread the thermal energy and exchange that into your hand and the air around the light.  That is why a lot of handheld lights have fins - to increase the surface area (again, same as in CPU heatsinks).  Designing and building LED lights is certainly a great hobby )


----------



## mattthemuppet2 (May 13, 2014)

great to see your work again Will, always a pleasure  I have a long list of LED projects to get started on once we move, not much point doing them beforehand.


----------



## Torbo (May 13, 2014)

wquiles said:


> I have this Dewalt 18V incandescent "lamp" what plugs into the Dewalt batter pack this model, in case anyone wants to buy one for a similar project.  I trade it/barter for it many years ago, and it has been sitting in a shelf in my home office - just sitting there, as I hoped to eventually do something with it.  I like it since with the heavy battery base, it can stand on its own, and have the head pivot at either horizontal or vertical, which might come handy.
> 
> 
> I wanted to take it camping with my son's scout pack on March, but I ran into some trouble, and I could not finish on time.  This weekend I finished it
> ...



Exilent! Impressing!


----------

