Soetta Soil Moisture Sensor Arduino Raspberry Pi Noncorroding Sensor Module Watering System 3.3V-12V (1 Pack)

Running on esp32 with 3.3v. AO is about 1.2v in water and 3.2v in air. Calibrated to that. after about a week in my garden with daily watering the max moisture percentage drifted down to negative. Corrosion?? So I then set it up on a PC817 optocoupler power by a GPIO from my board only when its time to read. Drift over time is much less but still degrading over time. I would assume all these resistive type moisture sensors hove the same issues.

Unlike other cheaper water sensors, this one is insulated so it wont erode and breakdown and release possibly harmful chemicals as it breaks down. I took seconds to connect it to my Arduino UNO and get data from it. If you are looking for a sensor to use with plants that is safe and will last spend the extra couple bucks and get this one.