Make Multi-house Water Pump Control System using Arduino

The Make Multi-house Water Pump Control System uses an Arduino Nano to intelligently manage and track water pump operations for multiple shared living spaces. Powering the system begins with a 15V 1A AC to DC power adapter, which is regulated down to a stable 12V by the IC-7812 voltage regulator, supported by 100uF electrolytic and 0.01uF ceramic capacitors to smooth out voltage ripples. The Arduino Nano processes control logic using software written in the Arduino IDE. Because the Arduino's digital output pins cannot directly drive high-current components, control signals are sent through PC817 optocouplers to provide electrical isolation between the low-voltage digital domain and the higher-power switching circuits. The ULN2003 relay driver then amplifies these signals to actuate four heavy-duty 12V DC 6A relays. Each relay channel incorporates 1N4007 diodes for flyback suppression to protect against inductive kickback, FZ5.1A Zener diodes for voltage regulation, and 5 mm LEDs paired with 10K and 15K resistors to visually indicate channel status. High-voltage connections are routed through a 12-way power terminal block strip, with each pump circuit protected by a 250V/500V 16A glass-fuse to ensure safety against overcurrent conditions while distributing shared water access.