I am using Genesis v.16 and FarmBot OS v15.4.1. Recently, I’ve noticed that the soil sensor readings fluctuate significantly, ranging from approximately ~230 to ~1000. I tested the sensor with a pot of very dry soil, and both readings taken 5 minutes apart showed ~1000.
I also tested the readings in air (~230) and in water (~530).
When I checked the UTM, I noticed some corrosion, as shown in the image below. Could this corrosion be causing the erratic readings? Thank you.
If the soil sensor is not seated on the UTM properly and the POGO pins are not making good contact with the soil sensor, it can cause random readings. Based on the information that you give in your post, that is the most likely issue that you are encountering.
You can go through these troubleshooting steps from our Tool Verification Troubleshooting Guide.
Using a dry toothbrush, you may want to clean off any corrosion that you see on the UTM electronics board.
Another thing that you could try is to disassemble the UTM and to change the position of the pogo pins. Over time, commonly used pogo pins loose their spring force and they will need to be changed out.
Pins A, B, C, and D are commonly used. The rest (E,F,G,H,I,J,K,L) are available spare components and so you can use them as replacement parts. Please review the following documentation:
If you are still having trouble after trying the above suggestions, you may consider a full replacement the UTM . Sometimes in climates with high humidity, this component can fail over time so it may be a good idea to have a few available spare parts.
I managed to clean off some of the corrosion on the UTM and swapped the pogo pins. However, I believe the issue may lie with the soil sensor. While I can mount and operate the rotary tool without any problems, I’ve noticed that the green light on the soil sensor doesn’t stay on consistently. Sometimes it is off or flashing, and I have to manually adjust the sensor to fix the issue when that happens.
If you believe that the soil sensor is faulty, you can replace that individual component.
However, I would suggest that you do a trace of all the soil sensor wires (VCC - Red, GND - Black, SIG - Yellow, SDA - Green, SCL - White) to each respective UTM terminal. Verify that each wire has good continuity to the soil sensor PCB.
Then connect the soil sensor tool to the UTM and trace each respective terminal back to the Farmduino PCB. The terminal that is not giving you good continuity back to the Farmduino is the likely the culprit.