A custom hardware project featuring a circular PCB designed to fit inside a Mason jar, creating a touch-sensitive LED light. The board uses an STM32L011 low-power microcontroller, a CAP1203 touch sensor, and an AP5724 LED driver. The PCB layout follows a polar grid with artistic elements including a tree and constellation stars etched into the soldermask. Power comes from a 400 mAh LiPo battery with carefully optimized standby modes, achieving up to 67 days in standby at 0.25 mA draw. Firmware was hand-rolled to fit within the microcontroller's limited flash after STM32CubeMX generated code proved too large. The project was made as a small-batch wedding gift for groomsmen.
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