What it is
A battery-powered lamp for a Helldivers cosplay helmet. A 9 V battery powers an ESP32 and an RGB LED with all three colours on, so it reads as white. A 2N2222A transistor switches the LED, and a 17-key IR remote controls it.
Remote
| Key | Mode |
|---|---|
| OK | on / off |
| 1 | steady |
| 2 | pulse |
| 3 | strobe |
| 4 | SOS |
| 5 | failing lamp |
Battery life
Bench's circuit solver puts it at 87.5 mA on (about 6 hours) and 39.7 mA off (about 13 hours) from a 9 V battery.
Notes from the build
The lamp stayed on at first. Pulling the transistor out turned the LED off, which showed the LED wiring was fine and the base was being fed from somewhere it shouldn't. The cause was a jumper one hole off from the base resistor's row. One OK press could also toggle twice, so the sketch now ignores OK for 600 ms after a toggle.
Bench's compact perfboard layout packs the circuit into 23 × 16 holes, which fits a 5 × 7 cm board.
