Graphite Pencil Soil Humidity Sensor

Yet another soil moisture sensor, this time using a pure graphite pencil i got from my local art supplies shop. Just break the pencil in half (shave any plastic covering, if any) and connect the rods to the analog comparator.

To make good contact with the graphite, I´d reccomend drilling a tiny hole and some tracks on the pencil to run the exposed wire around, and then cover it with as much electrical tape as my holder would allow me to have.

This also keeps the rod distances consistent between sensors.

Printed with support for the parts touching the heatbed.

The sensor in the picture has more than two years in operation with no hint of breaking up :D