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Problem with gas sensors. How many calibrations !! Please help. — Parallax Forums

Problem with gas sensors. How many calibrations !! Please help.

JoeJoe Posts: 184
edited 2011-02-18 18:48 in BASIC Stamp
Hi,

I am using the CO (Carbon Monoxide) Gas Sensor Module (code 27931)

My problem is that each time I turn off the sensor module because I need
to replace batteries (for example) I need to calibrate it again.

I am tired of calibrate it each time . I don't know if all CO modules from Parallax have the same problem.

Do you know ?

Thanks, Joe

Comments

  • $WMc%$WMc% Posts: 1,884
    edited 2011-02-16 19:03
    Were are you storing the Cal. data?
    '
    If its not in eeprom,Or in some nonvolatile storage, It will be lost every time you cycle power on the Stamp.
  • JoeJoe Posts: 184
    edited 2011-02-17 06:19
    Hi,

    These modules don't send data. The module sent a 0 or a 1 when gas
    is near to the set point.


    Please , could you confirm?
    Thanks, Joe
  • Mark KiblerMark Kibler Posts: 546
    edited 2011-02-18 18:48
    Joe,

    The carbon DIOXIDE sensor we're using in our project outputs data as millivolts, somewhere in the range of 2500 mV:

    http://forums.parallax.com/showthread.php?122688-ARLISS-Team-NH/page38 (look at the diagrams)

    You have to convert millivolts to parts per million of CO, or CO2. Read the lengthy discussion on our forum and you'll get a better idea. I suggest you read in and around page 36
    > 40 on our forum pages. Some excellent graphs and explanations are included. We had lots of help from others.

    http://forums.parallax.com/showthread.php?122688-ARLISS-Team-NH/page36


    Regards,

    Mark - ARLISS Team New Hampshire
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