Arduino is an open source platform and easy to use software. The chapter is about to discuss the advantages of Arduino with brief description to each Arduino board including UNO, MEGA and NANO. Arduino Integrated Development Environment is used to write the program for Arduino, this chapter elaborates step to step description of writing and compiling the program. Proteus simulator is also introduced, which is used for checking the feasibility of program and working of the designed system without actual implementation on hardware. Design steps are described for the beginners.