Energy Efficient Smart Street Light System based on Pulse Width Modulation and Arduino

Across the country, majority of the electric power has been utilized for street lights. These street lights are always ON throughout the night and even in day times due to inefficient street light monitoring systems. An enormous rise in population and waning of natural resources has necessitates the prerequisite of efficient street light system. Therefore, in this work an energy efficient smart street light system based on PWM and Arduino has been proposed. In this work, the power efficiency has been achieved through PWM by switching the brightness of the LED from 100% to 20% based on the vehicle traffic. Based on the vehicle traffic per hour, the duty cycle has been adjusted which inherently changes the width of the pulse. Initially, the lights are in OFF during day time regardless of vehicle movements(LDR is high); during night time or cloudy environment the lights are turn ON based on the vehicle motion detected by PIR. The brightness of the LED is 100% up to a specified time delay, thereafter the brightness has been reduced to 20%. These changes in stats of LED (ON/OFF) have been controlled by PWM duty cycle which is specified by analogWrite(). The performance measures have been evaluated for proposed system by means of power consumption. The experimental results demonstrated that, the proposed system archives a power save (delay of 3 seconds) of 95% with zero vehicle movement, 92% with 30 vehicles per hour, 91% with 50 vehicles per hour and 87% with 100 vehicles per hour when compared to conventional street light systems.