ESP32-C3 firmware for a DIY YubiKey companion: an RGB-lit case that mirrors the YubiKey LED and can "touch" the key on demand over BLE — driven by a key on your keyboard.
The full backstory (in Russian) lives at ut.buglloc.com/2026/05/whisk3r.
- A TEMT6000 light sensor watches the YubiKey's status LED.
- An ESP32-C3 reads the sensor and mirrors the LED on a WS2812B strip wrapped around the case.
- The ESP32-C3 also runs a BLE HID host that pairs with a keyboard and
listens for vendor-defined consumer-control usages (
0xF000–0xF01F). - On the matching command, it pulses a transistor that drives a copper-tape pad against the YubiKey's capacitive touch contact (same trick as H4ptiX / Twibby).
The intended companion is a NuPhy Halo75 V2 with a small QMK patch that adds
BLE_CMD keycodes — see
buglloc/nuphy_qmk_firmware.
Any QMK keyboard that can emit those consumer-control usages over BLE will do.
| ID | Usage | Action |
|---|---|---|
| 0 | 0xF000 |
YkTouch — pulse the YubiKey contact |
| 1 | 0xF001 |
InFire — toggle / hold the fire effect |
MIT © Andrew Krasichkov