Go Down

Topic: Measuring Kilo to Mega Ohm sensors (Read 734 times) previous topic - next topic

sagi4422

Hello,
I am newbie here and looking for some help in circuit schematics to measure sensors. The baseline resistance of the sensors are 100k-100MOhms and the resistance of the sensors can vary in the same distance, for example, sensor with 10MOhm baseline resistance can exhibit a change up to 90% of its baseline. The readout of the resistance should pass to a computer using Arduino. The working voltage of the sensor is 1V.
Any recommendations for such circuit ?

Thanks.
Sagi

pito

#1
Apr 22, 2013, 09:50 pm Last Edit: Apr 22, 2013, 10:31 pm by pito Reason: 1
You may consider a R->frequency or period converter (with help of a jfet or mosfet op-amp) and do measure the frequency or period with arduino.
See for example below - the period changes from ~1ms (100k) to ~650ms (100Meg). Do measure the period and make some calcs.
Mind the measuring a 100Meg large resistor requires a special construction.. ;)
The voltage on the sensor (Rx) is up to 3.7V (see the fourth picture).

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy