Measuring power network frequency using junk you have in your closet

So... The setup was already running and they happened to catch the Feb 8 in incident? What a luck!

There is open distributed monitoring for all kinds of signals, like seismometer networks, weather, ads-b... Is there anything like this for the power network? Like a reference design or an esp32-shield?

How would it look like if we were serious?

I would make it three phase, with direct coupling to also see the exact voltage changing over the day. Sometimes we have issues with local voltage rising too high and PV inverters shutting off. I'd like to see and log this. An audio ADC should be good, but needs three channels.

For distributed sensing and logging, you would need a reasonable accurate time synchronization. Raw ntp over internet might not be good enough, at least not for localizing fault propagation issues over the whole continent. Better stick a 5€ GPS module on there.

Anybody seriously working on this..?

I've been thinking about this for a while and did a bunch of research and planning, though had no time for building yet.

Stepdown transformer or 12V AC power bricks with barrel jack output are easy to get and cheap. Lower voltage, easier to measure and you outsource the safety/galvanic isolation.

Zero crossing ICs tied to GPS PPS signal. Add on ADC to measure voltage swings. Esp32 can record and compress data locally, only sending summary frequency, phase/time alignment.

This is obviously nice for outage detection too. For some extra cost add SD card for longer storage buffer and ability to backfill data once connection is restored. Small battery to not lose 1-2 minutes of time sync from GPS on powerup.

My last rough estimate was ~$40 for minimal single phase version and ~$100 for kitted out three phase battery backup, in volume of tens of units. That's pretty decent, I could then mail a couple dozen to people for free to get global coverage.

My main unsolved concerns were: liability (I don't want anyone to sue me if their house burns down), trust in data (it's easy to send spoofed garbage, so initially I would want only trusted parties to send, all data would be public of course), and the most important one: finding time and motivation next to my day job to do this.