I know this is a bad idea, but that does't mean I don't want to try it.
Powerline networking is a thing. It could well be they do this in the way I'm considering, but I'd imagine they probably transmit data by superimposing it onto the live waveform and then using filters to filter out the AC on the receiving end. That just seems more responsible.
That being said, is there any electrical reason why I couldn't design a transmitter and receiver that communicated over my house's neutral wire? Assuming it used a low voltage for transmission, say 5-10V, that wouldn't change the potential between live and neutral by any more than standard grid fluctuations would, so I don't think this would present a problem to other devices connected?
If it's relevant, I'm in the UK so we use a 230V@50Hz ring main in our houses.
To be clear. I know this is a bad idea, I probably won't actually do it. So please don't answer with don't do it.
I'm looking for answers as to why it wouldn't work, or why it would potentially damage other devices plugged into my house wiring.