Humidity sensor

Discussion in 'General Electronics Chat' started by mindyou, Jan 28, 2009.

  1. mindyou

    Thread Starter New Member

    Jan 28, 2009
    Hello to everybothy,

    I need some advises about how can I read RH of this kind of sensors. The sensor i´m using is hch 1000, and datasheet is here ->

    I´m using a ne555 astable mode, and i have an output square that changes its frequency as long as the sensor change his capacity.

    My question is, how can i convert this range of frequency to an dc voltage? Because i´m planning to use this dc voltage to an analogue input of a microcontroller.

    What do you advise?

    Best regards
  2. bertus


    Apr 5, 2008
  3. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    Microchip has a nice ap note on measuring capacitance directly with a microcontroller. Second, wouldn't it be less complicated to measure the frequency with the MCU instead of doing the analog conversion? Third, have you looked at the CAV414 capacitance measuring chip or the National LM2907 frequency to voltage converter chip?

    Finally, a simple low-pass filter/integrator will convert frequency to voltage.