Pointing a camera at a pressure gauge and recording a graph is something that I would have found useful and have thought about writing. Does software like that exist that’s available to consumers?

I'm pretty sure claude will one shot this for you, including making you a home assistant dashboard item if you ask it.

Look into opencv.

frigate can be setup to do this I believe, but its overkill. Openclaw could do it, slightly less overkill.