• DIY (you can modify it and improve it)
• Low cost equipment
• Easy and cheap replace of sensors
• Comprehensible air quality level indicator (good-green, fair-yellow, bad-red)
• History records
• Graphics
• Portable (battery included)

• M5Stack Core2 ESP32 IoT Development Kit
• TVOC/eCO2 Gas Sensor Unit (SGP30)
• Temperature, humidity & barometric pressure sensors: ENV II Unit with Temperature Humidity Environment Sensor (SHT30+BMP280)
• NDIR CO2 Sensors: Sensirion SCD30, SenseAir Sunrise

Visual Studio Code + PlatformIO (arduino libraries, ESP32 SDK)

• Publish first version
• Realtime data in text mode [done]
• Webserver [done]
• JSON output [done]
• Save history records
• New: Add LVGL library to improve interface (GUI)
• New: Include history graphics
• New: MQTT integration
• New: Home Assistant integration

• Readings each 1 or 2 minutes for battery powered devices.
• Calibration according to manufacturer CO2 sensor (minimum 20 minutes outdoors, avoid to be near persons, vehicles and other contaminants)
• Lifetime of NDIR CO2 sensors: 5, 10 or 15 years.

• Codos
• Anaire
• eMariete (project) (FAQ problemas)
• TTNMAD CO2 Free & this
• co2meter
• Medición de CO2
• M5Stack ESP32 Core Ink + SCD30
• CanAirIO Citizen network for monitoring air quality
• Medidor CO2 DYI. WemosD1-Wifi. Sensor NDIR. Oled. HA
• Air Particules Monitor
• Monitoring CO2 using APP (LILYGO TTGO T-Display ESP32 + Bluetooth (includes Sensirion APP) + Sensirion SCD30 CO2)
• LibreCO2
• CO2 Watch
• Zigbee + CO2 sensor
• Wemos D1 Mini + SCD30 + Thingsboard + Telegram
• Upload your CO2 data to public server and see on map
• Projects using traffic lights: Project 1, Project 2
• Power plug model: Components, source code, 3D model, assembly, schematic
• French makers

• Cupertino Truetype Font (icons)
• Font Converter (to use TTF o WOFF truetype icons in your C code, supports LVGL)
• truetype2gfx (to convert fonts to Adafruit GFX, you move icons to begin of TrueType font using FontForge)
• FontForge (font editor)

• Daily global CO2
• IAQ Rating Index (english)
• Aireamos project (spanish)
• Guía para ventilación de las aulas CSIC (spanish)
• Cómo ventilar las aulas pasando menos frío. Aulas como espacios saludables (spanish)
• CanAirIO Air Quality Sensors Library
• CO2 expelled by a person seen from a thermal camera (spanish)
• Improving Indoor Air Quality in California Schools

• Comparative table of commercial products (japanese)
• Teardown of several CO2 meters
• Aranet 4 (spanish info) (english info) (teardown) (forum)
  NDIR sensor: SenseAir Sunrise
• CO2Panel PI (spanish info)
• Carbon Dioxide Detector EM002 (manufacturer) (reseller) (interactive guide in spanish)
  NDIR sensor: Honeywell CRIR M1 / SenseAir S8 / Cubic CM1106 / ZyAura ZG09
• Dienmern DM306C (manufacturer) (distributor)
  NDIR sensor: Winsen
• Temp. RH CO2 Meter 7755 AZ (info)
• Temtop M2000 Air Quality Monitor (info) (video)
• Netatmo (teardown)