This triggers the alarm and shows a burglary attempt. A lamp is also used to indicate the theft when light falls on the sensor. In future, this project can be developed by using a GSM modem and also a microcontroller. This modem can be interfaced to send an SMS to the user in case of burglary. In the proposed system, generally the lighting up of highways is done through HID lamps. Because, the energy consumption of these lamps is high.
This project demonstrates the usage of light emitting diodes as a light source. These lights consumes low power and its life is more as compared to HID lamps. A light depending resistor is used to detect the light. The resistance of the LDR drastically reduces according to the daylight. A bunch of LEDs are used to make a street light.
The microcontroller comprises programmable instructions that controls the light intensity based on the Pulse width modulation signals generated. The light intensity is kept high during the peak hours, and as the traffic on the highways tend to decrease in late nights: and the light intensity also decreases till morning.
Finally, the street lights completely shut down at morning and continues again at evening 6pm. In future, this project can be developed by connecting it with a solar panel, which converts the intensity of the solar into corresponding voltage, and this energy is used to feed the street lights on highways. This sunset to sunrise lighting switch is designed to control the light illuminated on the LDR sensor.
The equation to show the relation between resistance and illumination can be written as. Values usually range betwee 0.
Practical LDRs are available in a variety of sizes and package styles, the most popular size having a face diameter of roughly 10 mm. They need very small power and voltage for its operation. Highly inaccurate with a response time of about tens or hundreds of milliseconds. Author jojo. April 27, These impurities or dopants create a new energy band above the existing valence band. As a result, electrons need less energy to transfer to the conduction band because of the smaller energy gap.
LDR frequency dependence The sensitivity of photoresistors is shown to vary with the wavelength of the light that is impacting the sensitive area of the device. Photoresistor applications Photoresistors are found in many different applications and can be seen in many different electronic circuit designs.
Derating may be applicable above a certain temperature. Maximum operating voltage Particularly as the device is semiconductor based, the maximum operating voltage must be observed. This is typically specified at 0 lux, i. Peak wavelength This photoresistor specification details the wavelength of maximum sensitivity. Curves may be provided for the overall response in some instances. The wavelength is specified in nm Resistance when illuminated The resistance under illumination is a key specification is a key parameter for any photoresistor.
Often a minimum and maximum resistance is given under certain light conditions, often 10 lux. A minimum and maximum vale may be given because of the spreads that are likely to be encountered. A 'fully on' condition may also be given under extreme lighting, e.
Dark resistance Dark resistance values will be given for the photoresistor. These may be specified after a given time because it takes a while for the resistance to fall as the charge carrier recombine - photoresistors are noted for their slow response times. Shopping on Electronics Notes Electronics Notes offers a host of products are very good prices from our shopping pages in association with Amazon.
Note: Electronics Notes receives a small commission on sales at no cost to you. Selected Video What is a Spectrum Analyzer? Supplier Directory For everything from distribution to test equipment, components and more, our directory covers it. Featured articles. This is the maximum power the device is able to dissipate within a given temperature range.
Particularly as the device is semiconductor based, the maximum operating voltage must be observed. This photoresistor specification details the wavelength of maximum sensitivity. Get help. Create an account. Electronics For You. Home Technology Basics. Please enter your comment! Please enter your name here. You have entered an incorrect email address!
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