moisture sensor

Guest,

Your question is a little vague...

Are you looking to measure moisture in the air (i.e., relative or absolute humidity/dew point), or in a solid material (e.g., wood, concrete, soil, etc.) ?

Different types of sensors and technologies are used - and can use differences in impedence (resistance), capacitance, or thermal conductivity to measure the moisture...

Wheatstone bridge

- current sensing

- feed back resistor of op amp = gain changing

- frequency change

all based on resistance changes de to humidity.

I made one out of a spring clothespin, two wires, and an aspirin tablet to turn on my pool pump while i was having my sump pump rebuilt.

water dissolves aspirin, clothespin closes circuit, turning on sump pump and ringing a bell to tell me to go turn off the pump.

I thought it was cool.

wife thought I was to use a del the cat term "daft"

but it worked!

milo