I wanted to try putting MELD into an 18650 light, so I looked around and found this: the Solarstorm SC02, which is a clone of the Olight S20. It's a pretty good buy at $15, better machining than I expected at that price. The firmware is awful, as is the norm, so I promptly gutted it:
I kept the original PCB and stripped off all components except the tantalum input capacitor. This build wouldn't make sense to use MELD hardware in since it will never run on a primary cell, and it should have a higher current on white than the 1.5A that MELD3 is capable of. This one would be run only on secondary cells so I used linear regulators controlled by a PIC16F1825 running the linear version of MELD 2.13 firmware.
The LED board was made using the two-layer method I came up with on my Blackshadow mod, so that the white XP-L gets better thermal performance.
I glued the PIC upside-down onto the stripped PCB and started wiring. The PIC needs 7 connections: 4 outputs, power, ground, and the switch input.
I then started stacking up the AMC7135 regulators. Here's the four that run the color components. They have a pair of wires that ground them together, and individual output wires that will run up to the LEDs.
After those 4 were wired to the PIC, I started on the 6 that will be paralleled to run the white emitter (at 2.1 amps). I made them in two groups of 3 to share the current load between two sets of wires, and to make them physically more flexible for when everything has to be fit into the pill.
Here are all the regulators wired up, insulated with kapton, and the wiring bundled into two groups to pass through the holes.
The driver fit fine, but I was just about at the limit of how much could be fit into the cavity. Here's the LED board going on, with thermal grease under it.
And here's the result of wiring in the individual LEDs.
To get the spacing just right, I cut the original plastic insulator so it had room for the extra LEDs, and then used it under the reflector.
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