Solar streets light with auto intensity controller

Abstract

The project is designed for LED based street lights with an auto intensity control that uses solar power from photovoltaic cells. A charge controller circuit is used to control the charging of the battery, and an LDR is used to sense the ambient light on day time. We have also at-tempted to measure the solar cell parameters through multiple sensor data acquisition. In this system, different parameters of the solar panel like light intensity, voltage, current and temperature are monitored using a microcontroller of the PIC16F8 family. The intensity of street lights is required to be kept high during the peak hours. The street lights are switched on at the dusk and then switched off at the dawn automatically by using a sensing device LDR LED lights are the future of lighting, because of their low energy consumption and long life they are fast replacing conventional lights world over. White light emitting diode (LED) replaces the HID lamps where intensity control is possible by pulse width modulation. A programmable microcontroller of the 8051 family is engaged to provide different intensities at different times of the night using PWM technique, for energy saving for solar based system, also using a charge controller for protecting the battery from over charging, overload and deep discharge protection. A light sensing device LDR (Light Dependent Resistance) is used whose resistance reduces drastically in day light for sensing purposes. In the measuring circuit the light intensity is monitored using an LDR sensor, the voltage by voltage divider principle, the current by current sensor and the temperature by temperature sensor.