infrared signal is used as the "trigger" for the operation of dc motors(or any other appropriate devices eg:LEDs).
i have used the arduino uno as the microcontroller as it simply does the job!also it's cheap too!!
future application will ultimately lead to IR controlled robot,and perhaps controlling of human mind using nothing but a simple remote control and interfacing hardware with electrodes,so that the physically disabled can attain normal "motor"...
IR controlled DC motors using arduino uno