how to know when the washing machine has finished

If you need to know when a device, like a dryer or washing machine has finished working, get a ‘smart plug with energy monitoring‘. Amazon list many of them but whichever brand you get, you’ll have more versatility if it can be integrated with your home automation platform. For example TP-link has the HS110 with energy monitoring and it connects with the Home Assistant platform. Home Assistant will have the more of the control features that we need than the TP-Link mobile app will have. If your energy monitoring smart socket is labelled Tuya / Smart Life / Sonoff POWR2 / Shelly PM there’s a good chance it works for this idea.

You just need a smart plug with energy monitoring

The idea is simple: leave the smart plug permanently switched on with the appliance plugged into it. Get your home automation software to monitor the current flowing via an automation routine. The routine needs to wait until the current to the washing machine drops below a low level eg 0.1 amp.

I can’t use the timer feature of a smart plug to turn on my washing machine. The washing machine needs an extra button press to start it after turning on. The smart plug CAN send me an alert when the cycle is finished ie the amp level drops and it CAN also total how much energy washing uses.

Other uses for a smart plug with energy monitoring:

• I don’t want my water immersion heater using electricity all the day. I use a Sonoff POW2 (shown above) to switch off my water heater when the tank thermostat switches it off.
• I might use an energy monitoring smart plug with an electric iron, or panini press or curling tongs or a charging laptop to ensure that a device isn’t left switched on. You need a home automation routine that watches for a raised current (say 1 amp) and then waits for say an hour, and then turns off the smart plug.
• This was a quick note to explain the idea: for more detail see my stop over-charging or water heater project.