whisli sense: ESP32 mmWave presence sensor with climate and light

whisli sense, by Tomasz Jaworski (tjaworski997), is a room presence sensor that also notices someone sitting still: its 24 GHz mmWave radar picks up the small movements of breathing, so presence lasts as long as someone is there, unlike a PIR motion sensor. Next to the radar it measures temperature, humidity and light. The hardware is a Waveshare ESP32-C3-Zero, a Waveshare HMMD mmWave radar (S3KM1110 chip; presence, distance and energy in 16 gates of 70 cm, up to 11.2 m), a Sensirion SHT30 for temperature and humidity and a ROHM BH1750 for light, all on the board's 3.3 V and powered over USB-C. Everything stays local, with no cloud or account: each sensor has its own web panel (Polish or English, light or dark) and a JSON API, and sensors find each other over mDNS with no hub. A 1.5-minute calibration wizard measures the empty room and a sitting person's breathing and sets every radar gate's threshold. The panel also shows a live radar view, 24-hour, 7-day and 30-day minimum and maximum climate readings, a status LED you can configure, diagnostics and an event log. Home Assistant is optional: over MQTT Discovery the sensor creates a device with occupancy, distance, temperature, humidity, illuminance and Wi-Fi signal. Ready firmware is in the repo's Releases (flash once over USB, update over Wi-Fi after that), or you build it with PlatformIO and Node.js. The author's working build is a breadboard prototype; a ceiling enclosure and a carrier PCB are in the repo's hardware folder, but as of 30 October 2026 the enclosure hasn't been printed and the PCB hasn't been ordered. Licence: the repo has no licence file, so no licence is granted.