High Intensity Discharge lamps (HID) (https://www.kitsguru.com/electrical-projects/intelligent-real-time-auto-intensity-control) used for urban street light are based on principle of gas discharge, thus the intensity is not controllable by any voltage reduction method as the discharge path is broken. In this kit White Light Emitting Diode (LED) replaces the HID lamps where intensity control is possible by Pulse Width Modulation (PWM). The intensity control helps in saving energy at late nights during which the traffic density is low.
Microcontroller from 8051 family is engaged to provide different intensities. The intensity gradually decreases from full intensity and then finally OFF.
This is very useful use full kit to automate the street lights on roads, or the lights in stadiums, especially in stadiums where the total intensity of the light is assumed to be constant. Here the LDR (Light Dependent Resistor) senses the environmental intensity of light and accordingly regulates the voltage at its output. At output we have DC bulbs connected whose intensity changes accordingly. It consists of manual as well as automatic mode of operation. The people can manual change the operation or in automatic mode the system operates according to physical change in light.
Post time: Jun-22-2017