Cheap and integrated CO2 sensors are finally available. I got mine from Athom . They cost $25 per device. The device uses an ESC32C3 (4M) as a foundation and sports a Sensirion SCD 40. It does measure CO2 in range from 400-2000 ppm with 5% accuracy (that’s the Sensirion Spec), and also acts as a Bluetooth Proxy (because the ESP32 can do that). Unpacking is easy enough. Connecting to the Wifi AP offered by the unconfigured device with an iPhone did not work (“Cannot join …”), but confi...
