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Thread: Sensing with Teensy 3.2

  1. #1
    Junior Member
    Join Date
    Mar 2017

    Sensing with Teensy 3.2

    hey guys.

    I am trying to read a voltage from a pH meter. The voltage that I am trying to read its from 2mV to 63mV. It is possible that the analog input from Teensy 3.2 read that voltage?

    I'm taking measurements from the positive and negative input that move the pointer in the pH meter.
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  2. #2
    Junior Member
    Join Date
    Mar 2017
    Never tried this, but I think that the AGND and AREF might help you with this.

    Edit: On second thought, I don't think AGND is related to the ADC, so please ignore this reply.

  3. #3
    Senior Member
    Join Date
    Feb 2017
    So, you’re trying to directly read the output of the pH sensor with the Teensy? I’m pretty sure pH sensors have a very high impedance and a low output level. This means you’re going to need a very carefully designed pre-amp to do anything useful with them. Or, does the pH probe already contain the pre-amp?
    Last edited by gfvalvo; 04-28-2017 at 09:00 PM.

  4. #4
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Indeed if it's a raw sensor, the impedance will be much too high when the pH is close to 7. You will need an amplifier.

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