Re:CO2meter: A Python interface to USB CO2 monitor devices
by Hasz on Friday April 03, 2020 @01:01AM
(#22766415)
For $20, you can get the MH Z-19, which is a NDIR type. You can talk to it over UART, and it comes in a 5000ppm and 2000ppm model IIRC. Decent documentation, and a good little sensor.
The S8-0053 looks interesting, but I have no experience with it. Also NDIR, boasts +- 40ppm accuraxy -- the room air might not even be that homogeneous...
The cheap ones are electrochemical, and they're not even that cheap.
Re:CO2meter: A Python interface to USB CO2 monitor devices
by polskibus on Friday April 03, 2020 @09:37AM
(#22768994)
Problem with it is that it autorecalibrates itself every 24hrs as far as I remember. It is a problem in room monitoring where you have constant high CO2- you'd have to take the sensor outside to fix it's reference level.
Re:CO2meter: A Python interface to USB CO2 monitor devices
by petsfed on Thursday April 02, 2020 @07:16PM
(#22764862)
The core device is typically on the order of $50-$150 US, but with many of the sensors that CO2meter sells, you're also getting a microcontroller, display, power supply, etc. You'll frequently find temperature and humidity sensors and also barometric pressure sensors rolled into that, since NDIR is affected by all those things.
So the price of a good, fully realized NDIR CO2 meter is comparable with any low-volume, moderate precision, moderate complexity electronic device.
Re:CO2meter: A Python interface to USB CO2 monitor devices
by Klinky on Thursday April 02, 2020 @07:38PM
(#22765005)
Andreas Spiess has a good video on VOC vs CO2 sensors.
Re:CO2meter: A Python interface to USB CO2 monitor devices
by Rebelgecko on Friday April 03, 2020 @01:05AM
(#22766432)
His channel is a goldmine for anyone who plays around with ESP-32 microcontrollers or similar devices
You're probably going 'Wow that's expensive for a CO2 meter when I can goto Aliexpress and get one for $10!' This is actually pretty cheap for a NDIR sensor which is what one should use for CO2 monitoring. The cheapo $10 sensors are all VOC sensors that require calibration and can be affected by airborne pollutants like alcohol.
I believe this is only 100ppm accuracy, the 5-10ppm resolution sensors are many hundreds of dollars. It's fine enough for casual air quality measurements.