This Washing Machine Monitor will notify you when the washing is done. Instead of using a timer, Viktor Takacs decides to use Freescale’s MMA7361 3-axis accelerometer to monitor the movement of the washing machine. The device is mounted on side of the washing machine using neodymium magnet. It is enough to absorb any vibration from the washing machine.
The brain of the project is PIC12F683 microcontroller. It read the sensor and processes the output. LED is for visual feedback of some parts of the operation and piezo buzzer as sound indicator. The project uses 4 rechargeable AA batteries as power supply.
How the system works
When you start the washing machine you need to switch on the device using the switch on the side of the board. The monitor provides a visible “heartbeat” pulse roughly every second. This gives you visual feedback to verify it is on. Also, whenever movement is detected it pulses extra – another visual clue to make sure it is operating as expected. Whenever it doesn’t detect movement for about a minute it stops the “heartbeat” and starts beeping. To start things all over you need to switch it off then on again.