convert capacitance signal to voltage signal

Discussion in 'The Projects Forum' started by sumani, Mar 13, 2009.

  1. sumani

    Thread Starter New Member

    Mar 12, 2009
    I'm an engineering faculty undergraduate, and new to this field. i m using HCH-1000 Capacitive Humidity Sensors for my project. now I'm facing a problem to connect it with PIC.
    i would like to know that how to interface this sensor with PIC micro controller. could you please suggest me a circuit diagram that can be used to connect humidity sensor HCH-1000-001 with the PIC 16f877a.

    or simply could you please suggest a circuit to convert capacitance signal to voltage signal
    capacitance varies in a range from 300 to 370 pF
    the required out put voltage is 2V-5V

    thank you
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    You could use the sensor as part of an oscillator and feed o/p to a frequency-to-voltage converter.

    Or you could charge the sensor with a constant current source for a precise time interval and then sample voltage.

    Or you could use the sensor as part of a capacitive voltage divider with AC applied, and run the o/p through an RMS converter.

    Or you can do this:
  3. thatoneguy

    AAC Fanatic!

    Feb 19, 2009