Handling moisture sensor corrosion

Slack Message from Kai

Below’s how my soil moisture sensor looks after 6 days continuously operating, quite corroded. I now switched to the method @Sam Freriks suggested here. I guess that it makes sense to use a digital pin (D1) to switch on the current/voltage to the sensor only while taking a measurement. Every 5 minutes or even longer intervals should be totally fine.

/reply from Sam Freriks
Woah corrosion goes fast! The method should slow it down quite a bit :smiley: nice idea to put a heat shrink around the connector btw!

1 Like

From Slack

Ben Blaine 3 days ago

checking this out as a non-corroding alternative moisture sensor https://www.robotics.org.za/CAP-SW-12

Ries 1 day ago

On the corrosion, I take a measurement every one hour for less then 75ish millisecond. And only in that period of time I turn on the probe, I can just see a very short flash on the probe. Somfar after a week no significant corrosion.

Ries 1 day ago

I am wondering if just with the esp we can make a capacitive version reliable, it just properly just a matter of measuring rise time after voltage is applied, properly need some series resistor of 100…500k… not sure what the average inductance is of the probe.

From Slack

Sam Freriks 17 hours ago

You can use a digital pin for the voltage needed instead of the 3v pin, and only enable when needed plant_tech_ams/README.md at master · OfferZen-Make/plant_tech_ams · GitHub