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CO Gas Sensor — Parallax Forums

CO Gas Sensor

stampedstamped Posts: 68
edited 2010-04-12 23:59 in Accessories
I am doing a bit of preliminary research into the Parallax CO gas sensor. Can the sensor be used to determine Parts Per Million of CO? I run an internal non-flued gas heater and I would like to build a home-brew CO PPM sensor to see how much is in the air in my living room.

Can this sensor output PPM numbers? I am thinking (without a lot of research) of making a simple LCD display on the PPM with a range of say 1 to 999 (or less, say 300ppm).

Post Edited (stamped) : 4/12/2010 4:09:07 AM GMT

Comments

  • John R.John R. Posts: 1,376
    edited 2010-04-12 05:13
    Neither the CO Gas Sensor or the CO Gas Sensor Module will directly give you a PPM reading.

    The Gas Sensor Module will only give you an On/Off reading based on an adjustable threshold.

    The Gas Sensor will give you a resistance reading that is proportional to the PPM, but you need to do some work to get there. You'll need to control the heating circuit, and then measure the resistance of the sensor element. There also needs to be some way to calibrate the sensor based on the environment (other gasses present, temp, humidity).

    If all you're after is a "rough" number and relative change, you could probably make some assumptions.

    If I were doing this for my personal safety, I think I'd at least want a commercial meter/sensor/warning device as a reference. There seems to be some "fuzzyness" in the sensor spec sheet.

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    John R.
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  • stampedstamped Posts: 68
    edited 2010-04-12 23:59
    Thanks John R, for the response. I am hunting around for a circuit so that I can get an approximate PPM. In a nutshell +/-10% will be fine in terms of accuracy.

    We have our Gas setup inspected by a Gas fitter who performs measurements annually. I would just like to have my own gauge more for amusement purposes than a highly tuned instrument.

    Any pointers on a reference implementation would be appreciated.
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