Seems like it's not really a great plan, but could maybe be made to work: https://electronics.stackexchange.com/questions/634852/externally-sensing-if-ac-curre

Seems like it's not really a great plan, but could maybe be made to work: https://electronics.stackexchange.com/questions/634852/externally-sensing-if-ac-current-is-being-drawn-over-a-power-cord https://electronics.stackexchange.com/questions/634852/exter... It's also possible that your machine lets off some elecromagnetic noise you can detect directly. The other thing you could try is put some sort of a microphone / vibration on it, then train a small NN on the waveform to distinguish between the washer and dryer.