LIGHT SENSITIVE ALARM A PROJECT REPORT

Submitted by

ASHUTOSHANAND SINHA PARTH JADHWANI NIKUNJ MEHTA

IN PARTIAL FULFILLMENT FOR PROJECT OF

BACHELOR OF ENGINEERINGIN

ELECTRONICS & COMMUNICATION(3rd Sem)

SHANTILAL SHAH ENGINEERING COLLEGE, BHAVNAGAR

GUJARAT TECHNOLOGICAL UNIVERSITY (GTU) NOVEMBER-2011

1

CERTIFICATE

This is to certify that this project report ”Light Sensitive Alarm Project” is a bonafide work of “Ashutoshanand sinha,Parth Jadhwani & Nikunj Mehta” carried out the project work under my supervision.

Signature of guide signature of HOD

Date:Place:

ACKNOWLEDGEMENT

Of the many people who have been enormously helpful in the preparation of this report on “Light Sensitive Alaram Project”. I

2

am especially grateful to Dr. S.B. Parmar, head of Department of Electronics & communication, who has always been providing me all possible help and resources required for preparing this report successfully. I am heartly grateful my Project Supervisor Mr. Manish Purohit who has always been rendering his untiring support, advice and encouragement for preparing this report without which it was not possible for me to complete the project so efficiently. I would like to give very special recognition to the respondents who have provided their valuable experiential feedback and at last I am thankful to my parents who co-operated me at every step.

CONTENTS

INTRODUCTION...........................................................................................................................5

PROJECT OVERVIEW..................................................................................................................6

COMPONENTS DESCRIPTION………………………………………………………………………….7

3

WORKING…………………………………………………………………………………………………10

APPLICATIONS & ADVANTAGES………………………………………………………………….....11

DATASHEET………………………………………………………………………………………………12

1.Introduction

The 8-pin 555 timer must be one of the most useful ICs ever made and it is used in many projects. With just a few external components it can be used to build many circuits, not all of them involve timing!

A popular version is the NE555 and this is suitable in most cases where a '555 timer' is specified. The 556 is a dual version of the 555 housed in a 14-pin package, the two timers (A and B) share the same power supply pins.

4

Low power versions of the 555 are made, such as the ICM7555, but these should only be used when specified (to increase battery life) because their maximum output current of about 20mA (with a 9V supply) is too low for many standard 555 circuits. The ICM7555 has the same pin arrangement as a standard 555.

The circuit symbol for a 555 (and 556) is a box with the pins arranged to suit the circuit diagram: for example 555 pin 8 at the top for the +Vs supply, 555 pin 3 output on the right. Usually just the pin numbers are used and they are not labeled with their function.

The 555 and 556 can be used with a supply voltage (Vs) in the range 4.5 to 15V (18V absolute maximum).

Standard 555 and 556 ICs create a significant 'glitch' on the supply when their output changes state. This is rarely a problem in simple circuits with no other ICs, but in more complex circuits a smoothing capacitor (eg. 100µF) should be connected across the +Vs and 0V supply near the 555 or 556.

The input and output pin functions are described briefly below and there are fuller explanations covering the various circuits:

Astable - producing a square wave Monostable - producing a single pulse when triggered Bistable - a simple memory which can be set and reset Buffer - an inverting buffer (Schmitt trigger)

2.Project Overview

The circuit detects a sudden shadow falling on the light-sensor and sounds the bleeper when this happens. The circuit will not respond to gradual changes in brightness to avoid false alarms. The bleeper sounds for only a short time to prevent the battery running flat. Normal lighting can be used, but the circuit will work best if a beam of light is arranged to fall on the light-sensor. Breaking this beam will then cause the bleeper to sound. The light sensor is an LDR (light-dependant resistor), this has a low resistance in bright light and a high resistance in dim light.

5

The light-sensitivity of the circuit can be adjusted by varying the 100k preset.

The length of bleep can be varied from 0.5 to 10 seconds using the 1M preset.

Parts Required resistors: 10k, 47k, 1M ×3 presets: 100k, 1M capacitors: 0.01µF, 0.1µF,

10µF25V radial transistor: BC108 (or

equivalent) 7555 low-power timer IC 8-pin DIL socket for IC LDR (light-dependant resistor)

type ORP12 bleeper 9-12V on/off switch battery clip for 9V PP3 strip board 12 rows × 25 holes

3.Components description

RESISTOR :A linear resistor is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element. The current through resistor is in direct proportion to

the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's terminals to the intensity of

6

current through the circuit is called resistance. This relation is represented by Ohm's law:

I = {V \ R} CIRCUIT SYMBOL :

CAPACITOR :A capacitor (formerly known as condenser) is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely,but all contain at least two electrical conductors Separated by a dielectric (insulator). Capacitors are used as parts of electrical systems, for example, consist of metal foils separated by a layer of insulating film.

CIRCUIT SYMBOL:

PRESET: 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 asimilar tool. The resistance does not vary linearly but rather varies in exponential or logarithmic manner.

7

Such variable resistors are commonly used for adjusting sensitivity along with a sensor.

CIRCUIT SYMBOL:

TRANSISTOR: A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, a transistor can amplify a signal.

CIRCUIT SYMBOL:

PHOTORESISTOR (LDR):A photoresistor or light dependent resistor (LDR) is a resistor whose resistance decreases with increasing incident light intensity. LDRs or Light Dependent Resistors are very useful especially in

light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as

8

high as 1000 000 ohms, but when they are illuminated with light resistance drops dramatically.

CIRCUIT SYMBOL:

9

4.WORKINGThis project is one of the alarm base project , which detects the sudden light falling on Light Dependent Resistor(LDR). In this circuit 7555 timer IC is used in monostable multi vibrater operating in edge triggered mode, which use less voltage to prevent excess of batrry voltage. After applying external voltage of 9V to the circuit is brought in active operation and bleeper make a sound for a while. Since our project is active,suuden change in light intensity will be detected by LDR. As a result bleepr will make sound. Duration of bleepr can be varide by using 100K preset to 0.5to10 second and sensitivity of LDR can be varide by using 1M preset.

10

5. Application S & ADVANTAGES : For security purpose. Burgerer Alarm For Counting Application For Speed Measurement Small circuit project. Low power supply required. Output can vary using pre-sets.

11

6.DATASHEET

7555 Timer IC:The ICM7555 is a CMOS timer providing significantly improvedperformance over the standard NE/SE555 timer, while at the sametime being a direct replacement for those devices in mostapplications. Improved parameters include low supply current, wideoperating supply voltage range, low THRESHOLD, TRIGGER, andRESET currents, no crowbarring of the supply current during outputtransitions, higher frequency performance and no requirement todecouple CONTROL VOLTAGE for stable operation.The ICM7555 is a stable controller capable of producing accuratetime delays or frequencies.In the one-shot mode, the pulse width of each circuit is preciselycontrolled by one external resistor and capacitor. For astableoperation as an oscillator, the free-running frequency and the dutycycle are both accurately controlled by two external resistors andone capacitor. Unlike the bipolar 555 device, the CONTROLVOLTAGE terminal need not be decoupled with a capacitor. TheTRIGGER and RESET inputs are active low. The output inverter cansource or sink currents large enough to drive TTL loads or provideminimal offsets to drive CMOS loads.

Pin Diagram:

The ICM7555 is a CMOS timer providing significantly improvedperformance over the standard NE/SE555 timer, while at the same

12

time being a direct replacement for those devices in mostapplications. Improved parameters include low supply current, wideoperating supply voltage range, low THRESHOLD, TRIGGER, andRESET currents, no crowbarring of the supply current during outputtransitions, higher frequency performance and no requirement todecouple CONTROL VOLTAGE for stable operation.The ICM7555 is a stable controller capable of producing accuratetime delays or frequencies.In the one-shot mode, the pulse width of each circuit is preciselycontrolled by one external resistor and capacitor. For astableoperation as an oscillator, the free-running frequency and the dutycycle are both accurately controlled by two external resistors andone capacitor. Unlike the bipolar 555 device, the CONTROLVOLTAGE terminal need not be decoupled with a capacitor. TheTRIGGER and RESET inputs are active low. The output inverter cansource or sink currents large enough to drive TTL loads or provideminimal offsets to drive CMOS loads.

FEATURES• Exact equivalent in most applications for NE/SE555• Low supply current: 80mA (typ)• Extremely low trigger, threshold, and reset currents: 20pA (typ)• High-speed operation: 500kHz guaranteed• Wide operating supply voltage range guaranteed 3 to 16V over fullautomotive temperatures• Normal reset function; no crowbarring of supply during outputtransition• Can be used with higher-impedance timing elements than thebipolar 555 for longer time constants• Exact equivalent in most applications for NE/SE555• Low supply current: 80mA (typ)• Extremely low trigger, threshold, and reset currents: 20pA (typ)• High-speed operation: 500kHz guaranteed• Wide operating supply voltage range guaranteed 3 to 16V over fullautomotive temperatures• Normal reset function; no crowbarring of supply during outputtransition

13

14