Here’s a slightly different way to check on the status of your laundry. Instead of checking if the machine is vibrating, or listening for sound, or pulling everything apart and hacking an ESP8266 into it, check the power that the machine is drawing. This is what [Scrand] did in his IoT dryer build.
The secret behind the hack is the Sonoff POW, a small device that sits in between the wall and the dryer. It has a relay in it that controls it, but, importantly for this hack, it’s able to measure the power consumption used by what’s plugged into it. By installing the ESPurna firmware on it, he can now use all the power of the firmware to control and monitor what’s connected to the POW. He wrote a PowerShell script to monitor the http server now running on the POW checking on how much power is being drawn by the dryer. When that power drops, the laundry is done, and in the case of [Scrand], a text is sent saying so.
When you’re sitting on the couch relaxing, why get up every five minutes to check your laundry when you can have it text you when you know it’s done? Then you can decide whether to get up and deal with it or just leave it until later. The whole reason ESPurna exists to begin with is to check on the status of the laundry. Or, you can go a bit overboard with this laundry room monitor.
Have you ever put a load of dirty clothing in the washing machine and set the cycle running, only to forget all about it and discover a mouldering congealed mass in the machine a few days later? [Xose Pérez] has more than once, and to stop it happening again he’s got a project that monitors the machine in his basement and notifies him when his wash is done.
At the centre of his washing machine monitor is an ITead Sonoff IoT mains on-off switch. This device contains a 10A mains relay, an ESP8266 chip to control it, and a small mains switch-mode power supply. The Sonoff doesn’t use the ESP’s ADC pins, so he’s broken one of them out on a lead to a current transformer which captures the power level being consumed by the washing machine. The Sonoff is one of those IoT devices that relies on a proprietary cloud service and doesn’t have its own API, so [Xose] has created his own firmware for it incorporating an ESP port of an Arduino current sensing library. To round off the project and because he could, he’s added an ambient humidity sensor to the device.
The resulting boxed-up unit returns minute-by-minute current readings for the entire wash cycle. To spot when the cycle has finished, he waits for a moment when it has been using no power for more than five minutes, at which point his Node-RED system sends him a notification via Pushover.
This project is a very neatly executed hack on an extremely cheap piece of hardware whose capabilities would ordinarily be somewhat curtailed due to its proprietary interface. Surprisingly it’s not the first laundry monitor we’ve seen here at Hackaday, we’ve had this apartment laundry monitor using an accelerometer and a Raspberry Pi, and a notifier for a finicky dryer that insisted on stopping mid-cycle.