Mick and I have been doing some testing with his soil moisture sensors over the last few months and he’s asked me to give an update on how it’s been going.
Mick posted Version 1 of the sensor to me with the waterproof plug connected to the sensor, leaving me to connect the other end to twin core cable.
He doesn’t have access to a Davis Soil Station and wanted to see how this sensor performed on a recognised system.
It came with instructions on how to connect the plug and also some heat-shrink connectors with low melt solder inside as an alternative. I went for the plug on this version and found it quite easy to assemble.
The sensor was then left submerged in water overnight and planted the next day, at a depth of 4cm.
It was connected to my Davis Soil Station and the data recorded in WD, then uploaded so Mick could see how it performed.
Performance wise, it is good and keeps track with the Davis Watermark sensor, although the readings are a lot higher and the Davis sensor is deeper at 8cm.
Mick produced a Version 2 of the sensor a couple of weeks ago and posted it up to me. On the outside it looks the same, so I assume he has altered clay mix, firing process or something else within the sensor to make it more sensitive.
With this one, I gave it 12 hours submerged in water, 12 hours drying, then another 12 hours submerged before connecting it to the Davis Soil Station.
When first connected, still submerged, it gave a reading of 8 Centipose on the Davis console (the reading for submerged should be zero). Unfortunately I didn’t do this test before planting the V1 sensor as a comparison. #-o
So the V2 sensor has been planted, again at 4cm, and is reading much closer to the Davis Watermark than the previous V1. Saying this, I do feel the Davis Watermark sensor is reading a bit too low because it’s currently at 4 Centpose and I know the soil isn’t that waterlogged at 8cm!
On the results of the tests to date with the V2 sensor, Mick is working on V3 to get it to read from 0-199 Centipose and we’ll be testing that when it’s ready next month.
In the meantime, Mick has asked that if there is anyone else with a soil station who would like to test one of these sensors, can they get in touch with him via PM.
He intends to make four of the V3 sensors for testing, so rather than relying on just my results, it would be good to have a few others trialled. 
Below is the live graph with all three soil moisture sensors and two soil temp sensor, so you can see how they’re performing.
