Time Based Intensity Control for Energy Optimization Used for Street Lighting

In this paper we have designed a simple, robust and energy efficient street light control system which requires minimum maintenance. The principle used is sensing time for deciding the intensity of the street light. The astronomical clock depending on geographical area is studied to generate statistical data. The intensity is varied in five steps as per the variations in ambient natural light obtained from the statistical data. The system uses micro controller, real time clock and MOSFET based driver circuit for controlling intensity of an LED array. Energy saving is 15.96 KWhr per street light per year in comparison with simple on-off systems. The system is more reliable than sensor based systems and requires less maintenance as compared to wireless sensor networks.