There is no other tool available which helps in easy prototyping like the Arduino does. The arduino board has all the required circuitry to get the built-in AVR microcontroller running. The output or inputs can be taken from the boards or given to the board using convenient connectors. Both digital and analog I/O pins are available in all Arduino boards. The arduino boards can also communicate with other devices using standard communication ports like USART, IIC, and USB etc. In this project a GSM module is interfaced with the Arduino board using the USART communication port. A PS2 keyboard is also interfaced with the Arduino board with the help of normal I/O pins. The keyboard can be used to type an SMS and the number to which the SMS needs to be send and the Arduino board will make the GSM module to perform the task.
The PS2 keyboard uses a simple synchronous serial protocol using only two wires for communication. Due to its simplicity the PS2 keyboards are widely used with simple microcontroller based boards also. The PS2 keyboard always acts as a slave device which can send the equivalent ASCII value of the key which has been pressed to its master device which can be a PC or a microcontroller.The SD memory card comes in large storage capacities from 1 GB up to 32 GB are available. They are used mostly in costly devices like digital camera, media players etc. The SD memory cards are interfaced in high end devices using SD bus which provides very high speed data transfer between the device and the memory card. They also can be interfaced with a device using the low speed and comparatively simple SPI bus and hence they are widely used in microcontroller based system also.
A key is the most basic input device for a system which can do some process. The key input can be found in electrical, electronic and mechanical devices. In case of the Personal Computers a group of keys are arranged in a single board called keyboard. The PC are mostly using QWERTY keyboard which has evolved from the mechanical typewriter device. Keyboards are interfaced in basically using two methods one is through USB port and the other through PS2 port.The PS2 is a simple synchronous serial protocol using only two wires for communication. Due to its simplicity the PS2 keyboards are widely used with simple microcontroller based boards also. The PS2 keyboard can send the equivalent ASCII value of the key which has been pressed. This project explains how to interface a standard ASCII keyboard having PS2 interface with the Arduino board.