Good morning Hydrosys friends, I need your help to solve a problem:

I have two water level switches coupled to the GPIO's of the irrigation board, each measuring the water level in a string of capillary boxes in the greenhouse.

Both are connected in the same way (GND and data), but behave differently. One of them does randomly shift level, despite the switch is not activated. I have tried to switch left and right switches, but the problem remain on the same GPIO pin, leaving switch and cable errors out of the equation.

Have you experienced anything similar?

Do I need to add a pull-up resistor to the GPIO?

I have attached a visual of the data as well as a logfile, showing the readings on the time of error.

Brgds

Lars