There's approximately a zillion devices with 7 segment displays, and half a zillion cameras that you can point at things. It's non-invasive and simple to understand. "Just disassemble it and solder in some extra wires" wouldn't fly for monitoring a thermostat in a basement or something, but a camera + rasperry pi might solve the problem at the right price + reliability intersection.

Back in the olden days of hardware RSA tokens, there were stories of people bridging out the TOTP values via setups like this. I've got an amplifier in the garage hooked up to a smart outlet that'll turn it on, but I have to go over there manually and rotate the knob from 20db to 50db.

I've been tempted to hack up some sort of "RC-Car Wheel + WebCam" to be able to remotely control/nudge the volume, but luckily my lack of free time prevents me from going off the rails like that. My other option is some sort of arduino and hacking at the rotary encoder circuit directly from the inside, but again (luckily) my lack of free time has kept the box closed.

The world's bigger than what you've seen so far, I'm guessing!