Arduino Based Washing Machine Timer

• Arduino Based Washing Machine Timer
  • Read Before Continuing!
  • 1. Introduction
    • 1.1. How To Use
    • 1.2. Requirements
  • 2. Installation
    • 2.1. Arduino
    • 2.2. Hacking Start Button
    • 2.3. Covering The Relay For Safety
    • 2.4. Testing Leaks
    • 2.5 Testing The System
  • 3. Photos

Read Before Continuing!

Washing machine, dishwasher and other machines operates at high voltage. Take precautions and always be careful. Wrong decisions may result in DEATH ! Main board of the machines include high voltage even on a simple button.

1. Introduction

There was two main problems:

• Odor comes from wet clothes stayed inside the machine for a long time (6 hours?)
• Noise of the machine

To overcome this problem, I simply set up a timer for the machine.

1.1. How To Use

• Short press will increase waiting time by one hour.

• Long press will reset everything.

• 7 segment display will show remaining time. Uses hexadecimal notation.

• When timeout, machine will be triggered by relay. (Same thing as pressing start button for 1 second)

• Designed finite state machine is located below:

1.2. Requirements

• PC

• A washing machine or a dishwasher which doesn't have timer function

• Arduino UNO and USB cable

• 5V Relay (for controlling 110V / 220V)

• 7 Segment display

• Button

• Wire, soldering iron, insulating tape, zip tie, hot silicone glue, insulating glove, voltage tester pen etc.

• A lot of caution (for staying alive)

2. Installation

Take insulation precautions before starting !

2.1. Arduino

• Install required libraries:

  • https://github.com/dgduncan/SevenSegment
  • https://github.com/jonblack/arduino-fsm
  • https://github.com/SofaPirate/Chrono
  • https://github.com/slavaza/SuperButton

• Connect Arduino, relay and 7 segment display together. Pin configuration located at CONSTANTS section in source code. Relay must be connected normally open.

• Test configuration with uncommenting //#define DEBUG line in source code.

2.2. Hacking Start Button

• Cut off electrics.
• Take of the main board of the machine.
• Locate start button and solder wires to it.
• Put back the main board to the machine.
• Connect wires to relay.

2.3. Covering The Relay For Safety

• Fully cover the relay with hot silicone glue. Do not left empty area.
• After silicone glue gone solid, cover it with insulating tape.
• Bind fully covered relay to a corner inside the machine using zip tie. It must not fall off.

2.4. Testing Leaks

• Turn on the electricity.

• Test every touchable/untouchable area with voltage tester pen.

• Test arduino pins related to relay. Also test relay pins.

2.5 Testing The System

• If you left DEBUG line uncommented, you can test now. Press few times and wait.
• When timeout, relay will close circuit for 1 second.

3. Photos