3. Use

3.1. Basic

3.1.1. Local display

Upon powering up there will be a short delay and following which sensor readings will shown on the display.

If the screensaver is activated, simply touch the screen to wake up.

3.1.2. Shutting down

The Raspberry Pi should be properly shut down before removing power. This can be done by pressing the bottom of the four black buttons.


Failure to shut down before removing power may result in data loss.

3.1.3. Restarting

If the device needs to be restarted, e.g. after making configuration changes, the following procedure should be used:

  1. Shut down

  2. Remove power

  3. Reconnect power


Soft reboot (without power cycling) will result in the CO2 sensor going offline.

3.2. MQTT

MQTT functionality can be tested by connecting via SSH and entering at the command prompt:

mosquitto_sub -h localhost -t '#'

Or Alternatively using an MQTT client on another computer and connecting to host airquality.local.

Sensor readings should be printed out every 5 seconds.