The mouse and keyboard are the basic input devices of a computer which can be connected with using PS2 protocol and nowadays with the help of the USB. The PS2 protocol is a simple two wire synchronous protocol which makes it possible for the simple microcontroller board to interface the standard PS2 mouse or keyboard with it. The PS2 mouse can continuously generate output data which contains the details of the movement in the X-Y plane and also the status of the buttons on it. The data read from the mouse can be decoded to get the amount of change in position of the mouse with respect to the position at the previous read. The mouse generates each set of data after equal interval of time and hence the change in position can be considered at the velocity at that particular interval of time. These velocities can then be used to find out the change in velocity for a number of periods and hence the acceleration can be found. 

The microcontroller based systems implemented in any kind of applications are actually stand-alone tiny computers. They can give output through display screens, loudspeaker etc. like a personal computer does. The microcontroller systems can take input also from standard input devices like keyboard, mouse etc. like a PC does. This article explains how to interface a standard PS2 mouse with the easy prototyping platformArduino.The arduino board is built around an AVR microcontroller and it has all the required circuitary to get the built-in AVR microcontroller running. The arduino can communicate with the other devices using its digital I/O, serial port, I2C port, SPI port etc. Any AVR microcontroller based board which follows the standard arduino schematic and is flashed with the arduino bootloader can be called an arduino board.