Dead Washing Machine Returns to Life with Arduino MKR

dawnchen Jan 27.2021

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Facing washing machine planned obsolescence with Arduino MKR (sure it works, it has new washing cycles and WiFi but... will it run Doom?)

Things used in this project

Hardware components

Arduino MKR WiFi 1010 × 1

Arduino 4 Relays Shield × 1

Nokia 5110Screen × 1

SCR 2000W Voltage regulator × 1

Zmpt101b × 1

DFRobot Gravity:Digital Push Button (Yellow) × 3

Software apps and online services

Arduino IDE

Autodesk Fusion 360

Story

Hacksung controlling a broken Samsung WS1702 washing machine

After 3 years, my Samsung WS1702 washing machine started to present erratic behavior. Several technicians had different diagnostics (motor carbons, motor coil, cables, pumps, electronic board) but after paying and fixing, the washing machine still doesn’t work and no one was able to explain why.

There is no better moment to open a big appliance than trash time, right?

7 pin washing machine motor

My washing machine AC motor has 7 pins (I was expecting 3 to be honest), so I had to learn a little about these connections. It was required to make a bridge between 2 pins (carbon and phase), apply AC over other 2 and the motor came to life at full speed.

Water in valves

Then I’ve identified valves, measure them, I’ve applied AC and they also seemed to be working.

Water out valve

So… motor was ok, pumps were ok… it seems just another case of subtle planned obsolescence.

Hacksung circuits

I’ve recently won an Arduino MKR in a contest – Original Arduino are not sold in Argentina – and I’ve decided this project worth it. After adding a 4 channel relay and some buttons I was able to manually control motor and valves. But… motor at full speed still needed a workaround. With a Voltage Control board SCR 2000W, motor was able to rotate at lower speeds as well: for example, slow movements to move clothing when water was coming in and full speed to dry clothing later.

Inside the Hacksung

I’ve added a Nokia 5110 screen and connected the MKR to my WiFi router, so when drying is finished, a notification is sent to the entire family through a Telegram group.

Telegram notifications

I’ve added an Extras submenu with dollar quotes (really important living in Argentina with 35%+ annual inflation)

Dollar quotes submenu

There is also a “Will it run Doom?” screen.

Will it run Doom?

Case has been designed using Fusion 360 in 3 parts and 3d Printed

Fusion 360 case

Work in progress

I’m now solving some issues related to automation. One of them is that motor power should be based on the weight. With certain motor voltage, some clothing and little water, motor goes full speed. With more clothing and water, it didn’t even start. So, it is required to measure motor RPM and adjust the voltage control accordingly. There is a tachometer included in the motor but readings are around 40v AC, so I’ve just added a Zmpt101b board to be able to read those values through Analog port A0. With those readings I will be able to change potentiometer values in Voltage Control unit.

Another thing to solve is motor reverse. The bridge has to be changed and one AC has to be assigned to another motor pin, so a 4 channel relay is not enough. I need at least 2 more channels and I could use also 2 more water in valves (hot water and pre washing smooth)

About washing cycles

My washing cycles are not called "Ecobuble" and things like that. Instead I'm using argentine writer names:

Adolfo Bioy Casares - Argentine writer

Lucio V. Mansilla: clothing like after a huge party with Ranqueles indians

Witold Gombrowicz: almost clean sailor clothing

Bioy Casares: clean and smooth, ready for a date.

Telegram integration

Telegram libraries didn't work for Arduino MKR, so I had to make a direct call to https with the bot ID and chat ID.

In order to get those ID's you need to:

Go to Telegram App, search botfather, send /start send /newbot

Go to t.me/sandoombot and get your token

Search idBot in Telegram App

Send /getId

Send a message to the bot created searching by link

Create a Group and add the bot

Load

https://api.telegram.org/botXXXXXXX:YYYYYYY/getUpdates

Extract the ID, like id: -1234567890

Test sending a message to the group with

https://api.telegram.org/botXXXXXXXXX/sendMessage?chat_id=-123456789&text=Washing

Finished

Final notes

Of course I prefer my washing machine to be working as it came from the factory but considering the circumstances, it was interesting to learn new things and to remember that hacking can be used to face planned obsolescence.

I hope this project could be interesting to other people facing similar situations or just wanting to enhance an old washing machine.

Version 0.1 code and circuits are provided here.

Case files can be downloaded here...

Just be very careful while working with AC and water.