Automatic Wash Basin Tap With LED Light

The Automatic Wash Basin Tap With LED Light circuit operates by combining power regulation, infrared object detection, and electromechanical water control with integrated illumination. Power originates from the mains via a 230V AC primary to 12V AC secondary transformer, followed by a 1A bridge rectifier and a 1000µF filter capacitor to convert the alternating current into a stable DC supply. The LM7805 voltage regulator steps this down further to provide a reliable 5V rail for control logic. When a user places their hands near the wash basin, the IR sensor module detects the reflected infrared light and triggers a low-level signal. This signal is processed using the NE555 timer configured to manage the timing sequence of the operation. The output of the timer drives the BD139 NPN transistors (T1 and T2), which act as electronic switches capable of handling the higher current needed to drive external inductive loads. When activated, the circuit switches the 12V normally closed solenoid valve to open the water flow. Simultaneously, the transistor switching arrangement powers the LED illumination array—comprising LED1 and the white LEDs (LED2 through LED10) with their corresponding current-limiting resistors—to illuminate the basin while the water flows.