Microcontroller based remote control system is a project design of a system that uses infra red transmission and reception principle to switch on or off other appliances. It is a wireless mode of switching appliances to a desired state. When a number is pressed in the transmitter section, the receiver section decodes the signal and utilizes it in controlling the desired appliances.

Several functional blocks of circuit are put together to ensure that the design works as the designer intended. These blocks include; the power supply unit, signal transmission section, signal reception section, the microcontroller unit and the voltage switching section. The power supply unit to the system comprises of a 12volts step-down transformer, a bridge rectifier circuit, a filter capacitor and a voltage regulator.

The signal transmission section sends out signals through an infra red transmitter situated in a remote. This signal transmitted is in the form of a frequency and only devices operating within that range of frequency can detect the transmitted signal.

Signal reception unit uses an infra red transmitter to receive the frequencies transmitted by the remote. The microcontroller section is used to decode the frequencies received by the infra red receiver and this is used to turn on or off the desired appliance. The microcontroller used is atmel89s51.

The voltage switching section uses relay in its operation. It receives signal from the microcontroller and ensures that appropriate voltage is supplied to the appliance being controlled by the operator.