4-Channel Touchless Switchboard For The Post-Covid World

The 4-Channel Touchless Switchboard uses an Arduino Uno to translate physical hand gestures into electrical commands without requiring any direct contact. At the heart of the system are four HC-SR04 ultrasonic sound sensors. Each sensor continuously emits high-frequency sound waves and listens for the echo to bounce back from a nearby object, such as a hand waving in front of it. The Arduino Uno measures the time it takes for these sound waves to return, calculating the exact distance of the hand. When a hand moves within a designated trigger threshold distance, the Arduino registers a command. It then sends a digital control signal from its output pins to the 4-channel relay board. Because the relay board uses a 5V low-level trigger, a low signal from the Arduino activates the internal electromagnetic coils of the selected relay. This mechanical switching action can safely open or close separate circuits connected to household appliances or lights. By mapping each of the four sensors to a different relay channel, users can independently control up to four different devices simply by moving their hand near the corresponding ultrasonic sensor.