This IR Remote Can Control Up To Eight Devices | Device Controller

This multi-device controller system uses an Arduino Uno, powered by its ATmega328P microcontroller, to process infrared signals and switch high-power loads. When you press a button on a standard TV remote, it emits modulated infrared pulses. The TSOP1738 IR receiver module captures these pulses, demodulates the 38kHz carrier wave, and sends a digital data stream to the Arduino. Using the IRremote library inside the Arduino IDE, the microcontroller decodes the specific button press into a command. Depending on which command is received, the ATmega328P changes the state of its digital output pins. Because the microcontroller pins cannot supply enough current to drive mechanical switches directly, the signals pass through a ULN2803 relay driver IC. This integrated circuit contains Darlington transistor arrays that safely amplify the low-current logic signals into the higher currents needed to actuate the eight electromagnetic relays (RL1 through RL8). These relays act as electrically operated switches that can physically open or close circuits for external loads. The entire control circuit is powered by a reliable onboard power supply: a step-down transformer reduces 230V AC mains voltage to 15V AC, which is then rectified using 1N4007 diodes and smoothed by filter capacitors. Finally, 7812 and 7805 linear voltage regulators step down and stabilize this voltage to provide clean 12V and 5V rails required by the relays and the Arduino board.