MHZ19: Difference between revisions
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The CO2 gas inside the air absorbs light strongly at very specific wavelengths, allowing a determination of the concentration (ppm) of CO2. | The CO2 gas inside the air absorbs light strongly at very specific wavelengths, allowing a determination of the concentration (ppm) of CO2. | ||
This is then compensated for temperature and pressure for increased accuracy. | This is then compensated for temperature and pressure for increased accuracy. | ||
See also [https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor wikipedia] for this measurement principle. | |||
A new measurement is started every 5 seconds, you can actually see a small amount of light coming out of the sensor while it's measuring. | A new measurement is started every 5 seconds, you can actually see a small amount of light coming out of the sensor while it's measuring. | ||
The MH-Z19 is the cheapest optical CO2 sensor I could find on AliExpress. | The MH-Z19 is the cheapest optical CO2 sensor I could find on AliExpress. | ||
Revision as of 10:05, 22 October 2016
| Project MHZ19 | |
|---|---|
| |
| Some research into the MH-Z19 CO2 sensor | |
| Status | Initializing |
| Contact | bertrik |
| Last Update | 2016-10-22 |
Introduction
This page is about the MH-Z19 CO2 sensor and some experiments done with it.
This sensor gives a digital (serial) output of the CO2 concentration in air, in parts-per-million (ppm). It uses the optical measurement principle of measuring CO2, which should be much more accurate than the inexpensive electro-chemical sensors you can find. As far as I know, the optical measurement principle uses a broadband light-source to send some light through an air-sample. The sensor then looks at the relative intensity of the light at two different frequencies. The CO2 gas inside the air absorbs light strongly at very specific wavelengths, allowing a determination of the concentration (ppm) of CO2. This is then compensated for temperature and pressure for increased accuracy. See also wikipedia for this measurement principle. A new measurement is started every 5 seconds, you can actually see a small amount of light coming out of the sensor while it's measuring.
The MH-Z19 is the cheapest optical CO2 sensor I could find on AliExpress.