Design of Intelligent Street Lighting Systems Based on Motion and Ambient Light Sensors

Street lighting is essential for nighttime traffic safety and public security, yet many conventional installations still operate at constant full brightness from dusk to dawn regardless of road activity. This practice causes unnecessary energy consumption and increases operational costs, particularly in low-traffic periods. This study aimed to design and evaluated a low-cost intelligent street lighting prototype that combines a passive infrared (PIR) motion sensor and a light dependent resistor (LDR) ambient light sensor to reduce full-brightness operating time while maintaining responsive illumination at night. An Arduino-based controller was implemented using a state-based control strategy with three operating modes: OFF during sufficient daylight, DIM standby at night when no motion was detected, and BRIGHT mode when motion was detected, followed by a configurable hold time before returning to DIM. The prototype was tested under four scenarios representing daylight, nighttime idle, nighttime motion, and motion stop conditions, with repeated trials and serial logging of sensor readings, state transitions, and pulse width modulation output levels. The results showed reliable state behavior across scenarios, rapid activation from motion detection to BRIGHT mode with a mean response time of 0.42 s, and consistent hold-time performance near the 30 s target. During a 30-minute nighttime mixed-activity test, the system operated in DIM mode for 62% of the time and in BRIGHT mode for 38%, yielding an estimated 43.4% relative energy reduction compared with an always-on full-brightness baseline. The findings indicate that integrating PIR motion sensing and LDR-based ambient gating provides a practical and replicable pathway to improve street lighting energy efficiency without sacrificing on-demand illumination for road users.