Joystick Breakout Board
This is a joystick very similar to the 'analog' joysticks on PlayStation 2 controllers. Directional movements are simply two potentiometers - one for each axis. Pots are ~10k each. This joystick also has a select button that is actuated when the joystick is pressed down. The joystick comes mounted on a breakout board and the pins are broken out to a 0.1" header and includes 4 mounting holes in the corners. There are 5 pins on board: VCC, GND, X, Y and Button. Connect the module with 5V power suppy with VCC and GND, you can read out the joystick status by X,Y and button pins. When using the 5V power supply, the default analog output for X,Y is 2.5V. With the direction of the arrow, the voltage up to 5V, and the opposite direction down to 0V.
Example Circuit- Joystick Controlling Servo