Carbon Monoxide Sensor

[skywatch]

Does anyone have a good suggestion for a co sensor that can be used with my sensors?

I don't need lab quality, just enough to tell me when to get out of the house and/or open the windows.

Thanks

[mfalkvidd]

@skywatch I have bought this sensor but have not had time to try it yet https://se.farnell.com/sensor-solutions-te-connectivity/2316852-1/sensormodul-i2c-5-95-rh-gjut/dp/2848274?CMP=i-bf9f-00001000

Edit: sorry, this is for CO2, not CO.

[skywatch]

@mfalkvidd NO worries - thanks for the reply. I just got a MH-Z19B running for CO2 yesterday. Amazing thing. From levels of about 400 on the landing it went to 1088 when I stir fried my supper!

Interestingly the dust sensor also peaked at the same time probably due to minute particles of oil in the air. I'm learning a lot with all this!

[alowhum]

@skywatch Yeah I had that same experience :-)

About the CO sensor.. I'm still looking for that too.

There's some basic debate about using

• a chemical based sensor (sensitive, but shorter life span)
• an electronic sensor (longer lastig, less precise, responds to other gasses)
• hacking a commercial Smoke/CO sensor.

I bought a CSS811 sensor thinking it could do CO (as a lot of Aliexpress stores market it as such), but it can't.

The MQ-type sensors are cheap, but they hardly work, and respond to a wide range of gasses (overlap).

This is an example of a 'chemical' sensor:
https://www.aliexpress.com/item/1pcs-ME2-CO-Industrial-Carbon-Monoxide-Meter-for-CO-Detector-using-electrochemical-CO-cells-Monoxide-Sensor/32844471365.html
(if I remember correctly there's a company called Figaro that is well respected when it comes to CO sensors)

Perhaps someone has tried this one.

[skywatch]

Well the co sensor has been running fine for many months now and I want to add NO2 and NH3 sensors as well in a module that can be used in the car in standalone mode and when docked in the house it can report to mysensors gateway.

So my question is, would the MICS 6814 above be a good choice?
Does anyone have experience of this sensor?

Thanks..... ;)

[alowhum]

From my experience I would go with the sensors that measures only that only that one thing you're interested in. The others tend to use some voodoo to get something close, even though they respond to a range of gasses.

So for example, that MICS-6814 might sense gas A and gas B. When it senses a lot of gas A it will tend to also report a lot of gas B, and vice versa.

[skywatch]

@alowhum Good point - I was hoping to make it small and portable to use in the car as well as in the home. With a lot of different sensors it will be more expensive, more bulky and therefore less conevnient.

[epierre]

MQ are always a bad choice, saturate air around with any gas and they will react ...

Mics are used by sensely, but even them aren ot calibrated... and they are a hell to get working even when you have the pins soldered to them.