A Traffic Light For Washing With Solar Power

Washing machine and dryer are the two big consumers where timing really matters: run them while the roof is producing, and the energy costs nothing extra.

The problem is that nobody wants to check charts before starting a load. So I built a small device that shows the answer in traffic light colours — green when there is enough surplus solar power, and so on.

It runs on ESPHome, a free firmware for small chips, and gets its data from Home Assistant. My wife and I just glance at it and know whether now is a good moment.