Intruder Alarm Using Ldr and IC555

Burglar/Intruder Alarm Using IC 555 and ldr

This is one of the most basic project for beginners. As soon you will cover ldr with your hand resistance will change and buzzer will go on ringing.   

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verified circuit diagram of intruder alarm using ldr

Infrared distance measurement system

Well don't you think how cool it is if we can calculate distance of some obstacle lying in front of us without moving from our place,so here is my guide on how to make a device which can do same using AT89C51 and ADC0804.

Here it goes:

Objective:

Major objective is to make a device that can calculate the distance of any obstacle in front of it by using IR sensors and can digitally display it on lcd.

Description:

     This project mainly consists of three units: a sensor unit,an ADC component and the LCD module. The IR receiver detects the IR radiations transmitted by an IR LED. The output voltage level of this IR sensor depends upon the intensity of IR rays received by the receiver. The intensity, in turn, depends on the distance between the sensor module and the obstacle. When the distance between IR pair and obstacle is lesser, more IR radiations fall on the receiver, and vice-versa. The receiver along with a resistor forms a voltage divider whose output is supplied as the input for ADC0804.

Components Used:

´IR LED | Infrared LED

An IR LED, also known as IR transmitter, is a special purpose LED that transmits infrared rays in the range of 760 nm wavelength. Such LEDs are usually made of gallium arsenide or aluminum gallium arsenide. They, along with IR receivers, are commonly used as sensors.

´Preset | Potentiometer

A preset is a three legged electronic component which can be made to offer varying resistance in a circuit. The resistance is varied by adjusting the rotary control over it. The adjustment can be done by using a small screw driver or a similar tool. The resistance does not vary linearly but rather varies in exponential or logarithm...

´AT89C51 or 89C51 microcontroller

AT89C51 is an 8-bit microcontroller and belongs to Atmel's 8051 family. AT89C51 has 4KB of Flash programmable and erasable read only memory (PEROM) and 128 bytes of RAM. It can be erased and program to a maximum of 10...

´LCD

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of applications. A 16x2 LCD display is very basic module and is very commonly used in various devices and circuits. These modules are preferred over seven segments and other multi segment LEDs. The reasons being: LCDs are economical; easily programmable; have no limitation of displaying special & even...

´ADC0804

Analog to digital converters find huge application as an intermediate device to convert the signals from analog to digital form. These digital signals are used for further processing by the digital processors. Various sensors like temperature, pressure, force etc. convert the physical characteristics into electrical signals that are analog in nature.

´Resistors

´Capacitors