Gypson Water Sensor

When measuring soil moisture down several feet you need a good sensor. Watermark makes a great sensor but it is quite expensive and needs a special circuit to read it properly.

A home made Gypson sensor is easy and inexpensive to make. It doesn't last as long but
it gives comparable readings to the professional sensor. It unfortunately needs the same circuit to read it properly but that is included. Simple to make and only has one critical component a .1 uf film capacitor.

I've made several of these over the years to monitor a couple of positions around my foundation that when they get too dry the building starts to move.

To build the sensor you attach low voltage outdoor light wire to 2 U shaped stainless rods. You need to silver solder them or use a spot welder to put on a nickel tab that is solder able.

Put the wiring in the printed form and poor in the Gypson. I've provided a chart to see how long it takes the sensor to become completely dry. I've also included