How to get temperature out of my solar water heater?


I want to read the temperature from my solar water heater controller. Is there a computer vision solution that can run on an old phone aimed at the display?

I thought about tapping into the temperature sensor that it’s already using, but I don’t want to compromise the controller’s operation.

I also thought about using the Fibaro Smart Implant to read the temp off a pipe, but that will be cool until hot water is flowing through the pipe.

I’m hoping that there’s a computer vision solution, or other option, to get the temp that the controller has.

If this should be posted elsewhere, please let me know.

Sorry, but I have never heard of such a device working with SmartThings.