An example for using MH-Z14A and Arduino Uno to detect CO2 level. It'll receive the result from MH-Z14A via pin 3,4 by UART communication and send the result via Hardware Serial (tx, rx) which is 0 and 1 in Arduino Uno.
MH-Z14A is a NDIR sensor.
- Make sure power supply range is stable and fit, or sensor might output very low number (e.g: 410ppm)
- At beginning (around 30 seconds), the sensor response is not correct.
- When doing zero point calibration, put MH-Z14A sensor in outdoor that CO2 level is 400ppm.