# MH-Z14A, MH-Z19B CO2 ... Module Arduino implementation for MH-Z CO2 sensors such as **MH-Z14A**, **MH-Z19B** and **MH-Z19C** (as I didn't find all info in one place). The sensor is available for ~20 bucks at the usual places. ## Implementation See example. > PPMuart: 602, PPMpwm: 595, Temperature: 23 ### Implementation details ``` C ppm = 5000 * (T_high - 2 ms) / (T_high + T_low - 4ms) ``` The implementation is mostly based on https://forum.arduino.cc/index.php?topic=525459.msg3587557#msg3587557 ## Resources: Datasheet (MH-Z19B): http://www.winsen-sensor.com/d/files/infrared-gas-sensor/mh-z19b-co2-ver1_0.pdf Datasheet (MH-Z19C): https://pdf1.alldatasheet.com/datasheet-pdf/view/1303687/WINSEN/MH-Z19C.html More info about the sensor: https://revspace.nl/MHZ19 ## Further reading: - http://ihormelnyk.com/Page/mh-z19_co2_meter (russuian, but google translate does a good job) - https://geektimes.ru/post/285572/ - https://geektimes.ru/post/278178/