I suspect that a power circuit in my home has an intermittent connection somewhere, and I'd like to test this to be sure (because if I'm wrong, then the equipment running on that circuit needs to be sent back for warranty repair).
I have the idea that if I can take either an isolating step-down transformer, or perhaps just a voltage divider, from the power rail, then feed it into an ADC on a micro-controller (probably ESP8266). I should be able to monitor continuously and trigger an alert, or record some data in a file in an SD card, if it detects that the rail has not reached a proper peak voltage within the last 1/60th of a second.
Obviously, I'm dealing with high enough voltage that it'll bite me if I mess up, and for that matter, if I divide carelessly, I could easily let the smoke escape from the ESP, but in principle I can get those things right. But, are there other concerns (or specifics about the above concerns) that might have eluded me?
It's also possible that there's a device cheaply available on the market that would do this, but if so, I've failed to find it. I'm happy enough to buy something if it's not too expensive, so if such a thing has a name, I'd be pleased to hear what that name is.