This is a low cost, and simple RF ASK based wireless joystick transmitter module. It is powered by a 5v supply, which in this version is connected via a 2 way header. The joystick module used here is a DEEK-ROBOT JOYSTICK-02, which consists of 2 pots, one for X, one for Y. The wipers are connected to analogue inputs of the Arduino Atmega328. These inputs are converted to digital by the Arduino and sent to the RF module. Many suitable RF modules are available, and all those tested seem to be interchangeable in that I've had no mismatch issues. It would be easy enough to modify the code to simply monitor the digital switches of an original wired joystick and possibly fit the board inside the joystick body, and then remove the cable of course.

You will need the RadioHead Arduino library by Mike McCauley installed in order to compile the code. I used version 1.122.1. The library is easy to find with google.

Please see my other projects for the matching RX board/Kempston interface.