A minor annoyance, but one that plagues me: when you put a wash on, forget
about it finishing, only to discover the damp washing hours later festering in
the washing machine. There’s only one thing to it - a massively overengineered
smart home solution!
Sonoff POW

This is a smart device that can be had from Chinese online retailers for ~$9 -
bargain. In it there’s a wifi microcontroller, the venerable ESP8266, a mains
relay and a current/voltage sensor to measure power usage. It’s the power
monitoring functionality this hack uses.
First, you need to solder on a header onto the POW in the usual place, and
flash custom firmware onto it (I’ve documented this process in the past, and
there’s good docs here). The firmware I used was
Tasmota - it’s a great piece of
fully featured custom firmware for the ESP8266 which includes wifi setup, mqtt
reporting, etc among others.
The rest of the wiring is dead simple - simply slice a single plug extension
socket halfway along the flex, and wire this into the Sonoff POW.

Then plug your washing machine into this and log into Tasmota to configure the
wifi connection and MQTT settings.
The rest of the process involves hooking this into your favourite home
automation system.
I’ve left this as a choice to the reader, below is how it
works with my home automation system
gohome, but it’d work equally well with
popular systems like Home Assistant.
I have gohome alerting me when the washing machine starts (which is triggered
by it detecting the power usage rising), and then 65 minutes later (the hour
cycle is a generous hour!), a following alert to say the washing is done. You
could alert after the power usage drops instead of doing it on a fixed time -
but that gets a bit more complicated to avoid false alerts on mid-cycle pauses
the machine does. A simply timer has worked well, as we only ever use the 1
hour program.
This was all done through a gohome
bot
that messages me through telegram.

Problem solved - so long as I see the alert on my phone!
There are comments.