3D printed 18650 light, playing with the idea

[PeterFH]

It bugs me that i still have to wait for the rest of the parts, i am tempted to use what i have just to see if i can talk to the LED driver.
But at first i have to see if the programmer even recognizes the whole thing:

http://i.imgur.com/dtPIS3X.jpg

 

[PeterFH]

Made a little bit of a mistake when routing the boards... made new ones today, wired it up and it passed the smoke test:

http://imgur.com/DFcAiJM

And we have contact, at lest the chip responds, that is not much of a feat, that is the most basic thing but the rest will have to follow:
http://imgur.com/sQrCk3l

 

[PeterFH]

Made a little bit of a mistake when routing the boards... made new ones today, wired it up and it passed the smoke test:

http://imgur.com/DFcAiJM

And we have contact, at lest the chip responds, that is not much of a feat, that is the most basic thing but the rest will have to follow:
http://imgur.com/sQrCk3l

 

[PeterFH]

Buttons work, status LEDs work and some parts are still missing, but it blinks:

https://www.youtube.com/watch?v=_5W2KEtiZzw

Just got the shipping notice for the rest of the parts, it looks like tomorrow i shall find out if the LED driver even works like intended.

 

[PeterFH]

The cooling of the LEDs will be a problem but i am dead set on building this thing so i always knew that i will have to make it work somehow.
Today i wanted to know how bad it will actually be, so i printed a small spacer to press the LEDs onto a tiny bit of aluminium, slathered on some thermal paste and wired it up with a thermocouple.

Not ideal but the best i could come up with, the thermocouple thouches the side of the small PCBs were the LEDs are soldered on to and sits in a hole filled with thermal paste, here are a bunch of pictures:

http://imgur.com/a/ivWbL

As you see, the LEDs get too warm, as expected, i cancelled the test at the 70°C mark, it was still climbing.
At 100mA@12V it stays at around 50°C, that is still too warm but manageable.

Later on i will get the saw out again, make a few more of the aluminium pieces and stack a few to see what will happen.

 

[PeterFH]

So... i had a productive day, i made a short video, the thing works.
I even made it a talkie and recorded it in color!

https://www.youtube.com/watch?v=fAF2qS8L6hI

And now for a bit of good news, bad news.

It seems either i did my math wrong or the circuit is misbehaving a bit, i poked and prodded it a bit with the scope and it seems to be working like it should.
And since i can barely count to five i will go with, my math was wrong.

The max current is around 160mA when running 4 LEDs in series, otherwise the regulator gets a bit toasty.
I say four since these LEDs have 2 dies in each package.
That either means i could stay with 2 LEDs and get more efficiency or just use one LED and run that one at 250mA, that should work but would be less efficient.
It should be a difference of about 15 Lumen/Watt, that is not much.
It makes more sense to just use one LED, that would mean, i only get 169 Lumen out of this thing, still enough for me but short of my target.

That was the bad news, now for the good news, all that means that the cooling is not as problematic anymore, two PCBs should do it just fine.
But i will test that.