Wood Sensor

Hi friends,

I am insterested is there sensor for wood moisture?
If there is where can it be ordered? If not, is there any alternative to measure wood moisture?

Thank you in advance.

Measure the conductivity using metal probes or capacitance using insulated probes.

I have connected one metal probe on pin 5.5V, and the other one on A0 pin.
The results that I get are not stable. There is very big difference between two measurements.
Is that the right way to do it?

Can you please explain me more about measuring with insulted probe?

Google says that wood moisture measures in the .75 to 4 megaohm (million or M) range.

What you need to do is put a ~2M resistor between 5V and the analog pin, then one probe is also connected to the same analog pin and the other probe is connected to GND. This is creating a “resistor divider”; the analog pin is comparing the resistance of the wood (GND through wood to analog pin) to the resistance of your resistor (5V through 2M resistor to analog pin). If you get a reading of ~512 on your analog pin that means the resistances are equal; your wood has a 2M ohm resistance. Everything else is a ratio, where (analog reading / 512) = ( Xwood / 2M ).

Because this resistance is so high you’re going to see a lot of variance in your readings when you move your probes around. It’s going to take some effort to write a sketch that throws out bad values and averages the good ones so that you can get a decent measurement.

Also see the tutorial on AnalogInput; the photosensor example is more similar to your case.

^ That.
And add a 100n capacitor from analogue pin to ground.
Wires, and a 2Megohm impedance, pick up a lot of hash.
The cap shortcircuits most of that, and gives the A/D a more stable voltage to sample from.
Leo…

I am sorry that I didn’t answer in time, I was very busy.
I did it yours way Chagrin, Wawa. Thank you all alot!
I got better with your help.