ESP32 Dark Sky Quality Monitor
SQMeter measures light pollution in real time using an ESP32. It gives you SQM magnitude, Bortle class, NELM, cloud cover, temperature, humidity, and pressure — all accessible from any browser on your local network.
- Docs: https://deanj87.github.io/SQMeter/
- Demo: https://deanj87.github.io/SQMeter/demo/
- Releases: https://github.com/DeanJ87/SQMeter/releases
- TSL2591 light sensor — SQM, NELM, Bortle 1–9
- BME280 — temperature, humidity, pressure
- MLX90614 — IR cloud temperature and cloud cover estimate
- GPS support (optional) — location and precise time
- RG-15 rain sensor support (optional)
- Real-time web dashboard over WebSocket
- REST API and MQTT publishing
- OTA firmware updates from the browser
- Captive portal Wi-Fi setup on first boot
See Flashing Your Device to get started with a new ESP32.
SQMeter is intended for a trusted local network. The current firmware has no web/API authentication, unauthenticated OTA endpoints, and exposes saved configuration through the LAN API. Do not port-forward the device or place it on guest WiFi.