“I based my design on the Wii Nunchuk controller for several reasons. First, it’s a versatile, comfortable, well-designed controller; second, it’s cheap and easy to find; and third, its native I2C serial protocol is easy to interface with Arduino. As a bonus, the connector will accept standard jumper wires, so there’s no need to cut up the cable or use a dedicated adapter. The Arduino runs a sketch that reads data from the controller and prints to the computer’s serial port. The computer runs a Python script, which receives serial data and emulates a mouse.”