Burgular Alarm Using IC555

Burgular Alarm Using IC555

 Abstract:

This circuit uses an IC555 timer. I.C 555 is connected as comparator with pin 6 connected with positive supply, the output goes high-1 when the trigger pin 2 is at lower than 1/3 level of the supply voltage. The output goes low-0 when it is above 1/3. So small change in voltage of pin 2 is enough to change the output state of pin 3 from 1 to 0 and 0 to 1. The output has only two states high and low and can not remain in any intermediate stage. It is power by 9V battery for portable use. The circuit is economic in power consumption. Pin 4,6& 8 is connected to the positive supply and pin 1 is grounded.

      To detect the present robber we have used LDR and a source of light.
LDR is a special type of resistance whose value depends on the brightness of the light which is falling on it. It has a resistance of about 1 megaohms when in total darkness,but a resistance of only about 2-5 k ohms when brightly illuminated. It responds to a large part of the light spectrum.
      The source of light and LDR is so adjusted with a reflector that light will directly fall on the LDR but when robber enters inside then it will block the beam of light and LDR will be under darkness.
      We have made a potential divider circuit with LDR and 100 K variable resistance connected in series. Voltage is directly proportional to conductance so more voltage we will get by this divider when LDR is getting light and low voltage in darkness. Sensitiveness can be adjusted by variable resistance. Divided voltage is given to pin 2nd of 555. As soon as LDR gets dark the voltage of the pin 2 drops 1/3 of the supply voltage and pin 3 gets high and Buzzer Beeps.
For Demo we have used simple LED for LED1 may be Red or White Color

Components:-

1) 9V battery with switch
2)LDR(Light Dependent Resistance)
3)Variable resistance
4)Resistance
5)LED(Light Emitting Diode)
6)IC 555 timer
7)Switch

Circuit Diagram:

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Convert Salt Water To Pure Water

Convert Salt Water To Pure Water

About The Project:

Abstract

Nowadays, water is becoming a big problem allover the world. The demand for the drinking water is keeps on increasing. This is a project to convert the salt water into drinking water. By using this type of project, we can reduce the demand for the drinking water. In future by improving this project, we can convert the seawater into drinking water.

The principle we are using in our project is that the salt water which is heated above its boiling point will converted in to steam and the salt content in the water will be deposited in the bottom of the container. The evaporated water is connected in another container through the steam valve and the water out valve removes the waste water.

In the second container, the steam will travel in the valve, which is cooled by a cooler. Thus the water vapor from the valve gets cool and again converts into water. This water vapor converted into water does not contain the salt content and it can use also for drinking. This the nature friendly project that can be used in every house to convert the salt water into pure water.

 

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Air Flow Detector

Air Flow Detector

About The Project:

This circuit can give a visual indication of the rate of air flow.It can be also used to check whether there is air flow in a given space.

The filament of a incandescent bulb is the sensing part of the circuit.When there is no air flow the resistance of the filament will be low.When there is air flow the resistance drops , because the moving air will remove some of the heat generated in the filament.This variations in the resistance will produce variation of voltage across the filament.These variations will be picked up by the opamp (LM339) and the brightness of the LED at its output will be varied proportionally to the airflow.The filament L1 can be made by removing  the glass of a 40W incandescent bulb.
.The circuit can be powered from a 12 V DC power supply.

Circuit diagram:

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Automatic Street Light Control

Automatic Street Light Control

About the Project:

The circuit diagram present here is that of a street light that automatically switches ON when the night falls and turns OFF when the sun rises. In fact you can this circuit for implementing any type of automatic night light.

The circuit uses a Light Dependent Resistor (LDR) to sense the light .When there is light the resistance of LDR will be low. So the voltage drop across POT R2 will be high.This keeps the transistor Q1 ON. The collector of Q1(BC107) is coupled to base of Q2(SL100). So Q2 will be OFF and so do the relay. The bulb will remain OFF.

When night falls the resistance of LDR increases to make the voltage across the POT R2 to decrease below 0.6V. This makes transistor Q1 OFF which in turn makes Q2 ON. The relay will be energized and the bulb will glow.POT R2 can be used to adjust the sensitivity of the circuit.You can use bulb of any wattage, provided that relay should have the sufficient rating.The circuit can be powered from a regulated 9V DC power supply.The relay K1 can be a 9V SPDT relay.

Circuit diagram:

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