Soilwatch 10 erratic readings

[liddelljs]

Hi all,
New to the forum and I have had a soilwatch 10 operating for about a month now.  Was initially getting very stable readings as per the first attachment (Moisture1) but the readings have recently become very erratic (moisture2) with very big swings between each hourly reading which can't be real.  The sensor is connected to a Wemos D1 R2 board with a 12v power supply via the 9-24V barrel jack.  The only thing I'm wondering is whether it could be a power supply issue as the supply is about 7 metres from the Wemos board.  Unfortunately the moisture sensor is at our holiday house about 250 Km from where I live so can't just step out the back and do some checks.

Hoping someone can give me some pointers.

Steve

[pinolec]

Hi Steve,

Welcome to the forum!
The readings got really erratic on the second graph. But I see a few strange readings on the first graph as well. I think the power to the board is OK as on the graph you have WiFi strength reports. I would suspect connections of the sensor. Do you have the sensor wires soldered to the board or screwed? Breadboard for a long-term project is not recommended as with time connections go bad. How do you power SoilWatch sensor? It's hard to diagnose without actually check it all.
When you have a chance you can test the sensor with a multimeter in the air and in water.

If it is a problem with the sensor, we will send you the new one.

[liddelljs]

Hi,
Thanks for the prompt response.  At present the sensor is connected to the board header pins directly with standard arduino connecting cables but they aren't soldered.  The connectors just slide over the header pins so I guess every chance one of the connections is problematic.  Power supply is from a 12V transformer but, as I mentioned, is located about 7m away from the board.
I'll solder the sensor directly to the board and see how it goes.  Will probably be a couple of weeks until I am next at the house so will report back when I have tested.

Cheers
Steve

[pinolec]

Hi,

Before you solder the sensor to the board check if the sensor works with a multimeter.
Let us know when you check the sensor.

Best,
Piotr

[liddelljs]

Hi Piotr,
I've checked the sensor and all seems good.  Measured 2.83V in water and 150 mV in air which matches values you quoted in another post.  I have soldered directly to the board and has been stable for 24 hrs or so.  Will keep monitoring and report back if I strike trouble again.

Many thanks for your help.

Steve

[pinolec]

Hi Steve,

I am glad all works well. If you have any issues with the sensor then let me know.

Kind regards,
Piotr