Measure resistance using arduino

[beakie]

Anyone know a technique?

I can get the voltage using an analog in pin... what about the current?

Cheers
G

 

[CafeLogic]

Use a reference resistor and compare it. For example, you want to know the resistance of something you expect to be in the range of 2k. Connect VDD to unknown, unknown to 1k ref, then 1k ref to ground. Connect junction at unknown and 1k ref to ADC. Assuming the ADC is 10-bit, and VREF is set at VDD, the ADC will read 341 because the voltage at the pin will be 33% of VDD.

 

[beakie]

Thanks man

 

[Russ Hensel]

A common method is to use a constant current circuit to drive the resistor and then just measure the voltage.