ABSTRACT:
Automatic Street Light Control System is a simple yet powerful concept, which uses transistor as a switch. By using this system manual works are 100% removed. It automatically switches ON lights when the sunlight goes below the visible region of our eyes. This is done by a sensor called Light Dependant Resistor (LDR) which senses the light actually like our eyes. It automatically switches OFF lights whenever the sunlight comes, visible to our eyes. By using this system energy consumption is also reduced because nowadays the manually operated street lights are not switched off even the sunlight comes and also switched on earlier before sunset. In this project, no need of manual operation like ON time and OFF time setting. LDR and Microcontroller are the main components of the project. The resistance of light dependant resistor (LDR) varies according to the light falling on it. This LDR is connected as biasing resistor of the transistor. According to the light falls on the LDR, the transistor is operated in saturation and cut off region. This transistor switches the relay to switch on / off the light. The output of the solar panel depends on the intensity of the solar light. Use of embedded technology makes this system efficient and reliable. Micro controller (AT89S52) allows dynamic and faster control. Liquid crystal display (LCD) makes the system user-friendly. AT89S52 micro controller is the heart of the circuit as it controls all the functions. In this project the usage of solar energy by using solar panels are used .A voltage sampler is interfaced with the system to get the voltage stored in the battery to get a display on a 16X2 LCD. A crystal based solar panel is used to charge a rechargeable battery of 6V. LED based lighting is arranged in this project for energy saving application. Additional battery charger circuit is provided for emergency applications. This charger uses regulated 5V, 750mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/18V step down transformer.