Controlling a washing machine motor with an Arduino
In a modern washing machine, the moter that spins the drum is controlled by a motor driver, which is separate from the main control board that manages the washing cycle. The main control board sends commands that set the speed of the motor, and the motor driver generates the three-phase power needed for the motor and regulates the speed of the motor. In this article I will explain how I reverse engineered the motor driver (Magnetek 4246-99-1) from a washing machine and then controlled it with an Arduino. Reverse engineering the original setup In the washing machine, the motor driver received mains power through a relay on the main control board. The motor driver was controlled by the main control board via a 5-pin cable. The pinout is shown in the image below: The main control board communicates with the motor driver using an SPI bus. Data is transmitted in bytes with the most-significant-bit first. On the rising edge of the clock signal, the main board updates the signal on the MO