~derf / projects / CO₂ Monitor
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A CO₂ monitor with Home Assistant and InfluxDB integration implemented in NodeMCU / Lua. It shows the current CO₂ concentration and MH-Z19 temperature on a 128×32 SSD1306 OLED and makes them available to Home Assistant via MQTT. It can also publish readings to InfluxDB.


  • Display for CO₂ and temperature
  • Home Assistant integration via MQTT
  • Optional logging to InfluxDB
  • Powered via USB


  • Processor: ESP8266
  • CO₂ sensor: MH-Z19
  • Display: 128×32 OLED via SSD1306 (128×64 also supported with some changes)