LDRs are very useful components that can be used for a variety of light sensing applications. As the LDR resistance varies over such a wide range, they are particularly useful, and there are many LDR circuits available beyond any shown here. In order to utilise these components, it is necessary to know something of how an LDR works, which has been explained above. (ERT, Light Dependent Resistor, LDR, Vewied 30 August 2010,)

automatic street light controller using ldr

Advantages By using this Automatic system for street light controlling, we can reduce energy consumption because the manually operated street lights are not switched off properly even the sunlight comes and also not switched on earlier before sunset. In sunny and rainy days, ON and OFF time differ noticeably which is one of the major disadvantage of using timer circuits or manual operation for switching the street light system. Disadvantages1. A single LED low power. In order to obtain high power, require multiple parallel to use. 2. Color rendering index is low. Under the LED light shows the color of the incandescent light bulbs, not real, it will come up from spectral distribution analysis, belongs to the technical problems. 3. The light spot. Due to the defect on manufacturing process to add white LED and the matching of the reflective glass or lens error, easy to yellow problem. 4. The problem of the LED light evennessIf not the secondary optical design, the LED light is more concentrated, so be sure to the secondary optical design, make the light intensity distributionFigure a bat form mini integration LED street light. 5. The LED light failure problemCompared with the small power LED, high power LED street lamp light failure will be much better. But small power LED heat dissipation is very small. And high power LED is heat there is no way to solve the problems, and after the fever brightness will decrease, so the power not to do. Now the largest market sales Spark LED street light is 360 w