Solar pocket light white
Using the colorful Solar pocket light
it turns out a pocket light with white LEDs would be more useful.
Having a second PCB from the first version left, the schematic required only
minor modifications. The red green and blue LED were replaced by warm white
ones and instead of the UV LED, there is a red one.
The voltage was lowered from 4V to 3,5V to fit the forward voltage of the white
LEDs with better efficiency.
The software was adjusted to this new voltage and instead of a colorful disco
mode, there is now a simple flashing mode.
Because the reset pin is used as I/O pin, a HV programmer
might be required.
A custom aluminum case
Instead of using a cheap plastic case, a custom aluminum case has been
designed and milled.
This took a long time and did not always worked as expected, but was a good starting point to learn how not to mill.
The use of a rechargeable battery with a soldering lug saved the space of a battery holder and therefore allowed to make the case 2mm thinner.
So for the bottom part an 8mm plate of EN AW-7075 was used.
The upper part requires a plate with a thickness of 10mm.
Having 1mm overlap, this results in a case with 17mm in height.
The solar cell requires a piece of Plexiglas with a thickness of 2mm.
Both parts of the case are hold together with a 4mm screw.
From the outside
The two half shells with the PCB, battery and solarcell. And two wooden shells milled for testing.
Upper half of the case in FreeCAD
Lower half of the case in Heekscad
Software and schematics
As always, use at your own risk.