Yup. I live on a river. We flooded catastrophically in 2019, which made me suddenly care about the government’s network of river level meters.

Turns out, they abandoned most of them in 2008, as it was the local council who were meant to maintain them, but they couldn’t afford it - a chat with the president revealed they’d been paying €15k a year for each station to maintain it and they’d cost about €100k each.

I went and looked at the battered remains. Sounding tube. Ultrasound transducer. Box of 90’s electronics.

Anyway, long story short I banged out six of them for them for about €80 a piece - the expensive bits were the batteries and the dinky solar panel. ESP32, ultrasonic transducer, GSM and LoRa (as two are outside of the cell network), haven’t had to touch them in five years and we now know when it’s time to evacuate, rather than wading out in the night while trees sail past us at 60kph.

So much stuff like this.