How to Make a Burglar Alarm Circuit for Your Home Security?

These days home security systems are given great importance everywhere. However these security automation systems are very expensive to implement. Here I will help you to make a simple IR security system by your own using an Infrared-photodiode pair.

Earlier we had already published another intruder alarm circuit diagram which was based on LASER and LDR. However it has a probability that the thief might see the LASER beam and avoid theft alarm easily. This simple circuit will give you an insight into how do burglar alarms work.

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Simple Continuity Tester Circuit Using 555 Timer

Normally we use continuity testing to check if a circuit, PCB or cable is continuous or not. It also helps us to check if a bulb is burnt out or not. Simply we can do the test by using a battery and a led or buzzer, but they are not precise or accurate.

Usually we use a continuity test multimeter which is little bit costly and bulky too. Also these give a positive indication even when there is 100 ohms of resistance between the probes.

So how to make a continuity tester which has no such kind of drawbacks. This circuit is built around a common 555 chip wired in astable mode. The continuity test circuit can precisely judge continuity as that low 6 to 8 ohms(which can be set by using the preset). Speaker is used to indicate the continuity.

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Home security alarm system circuit diagram

Have you ever thought about implementing your own home security alarm systems? It's one of the simplest and interesting circuits for electronic beginners. Our new home security equipment uses a LDR (Light Depended Resistor) to detect security problems. Theft attempt and other security threats can be controlled by using this simple circuit to improve your security systems. This is also best suited for school students for their high school science projects.

To implement this alarm system for home, you have to provide an optical path (with LASER beams) around your home. The LASER path is made possible with one LASER torch and 3 mirror arrangements which encloses the whole area. Please refer the project arrangement section below to make this optical (light) path. We have explained about home security system in detail with animation/ simulation.

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Simple fire alarm- thermistor circuit diagram

Here i-St@r comes with a simple and automatic fire alarm and detection system. This fire detection alarm circuit is based on thermistor. What is a thermistor? A thermistor is nothing but a variable resistor whose resistance increases as temperature decreases. Fire detection is simply possible via this low-cost alarm circuit.A simple potential divider arrangement using thermistor is capable of sensing the temperature (presence of fire) and alerting us with a warning signal. This is suitable for your home security systems. Also school students can do this fire detector circuit as their high school science fair projects. Here I will explain in detail about fire alarm circuit wiring with animation/ simulation of fire alarm.

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Low water level indicator alarm circuit for Water tank

Most of the time we wish to have a water low level alarm (liquid level alarm) circuit to know if the amount of water inside the tank has decreased in order to switch ON the water pump set. Don’t worry about that, we can implement a simple water low level indicator sensor alarm circuit for your home or office with the help of liquid level probes. Our water level sensor alarm detects the fluid level using a transistor switching circuit. We have already discussed about different types of fluid level alarms and water tank level indicators, they are mainly to detect overflow from the water tank. But this one indicates that the tank is near to be emptied.

(This circuit is posted as per the request from one of our reader MR. Ramz)

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UM66 based Water tank over flow musical alarm circuit

This is a simple home automation project based on UM66 melody generator IC. Water tank overflow musical alarm is best suited for science projects in schools. In one of our previous article we had already discussed about another liquid level sensor alarm circuit that produces a beep sound, but this circuit gives a melody sound whenever water in the tank over flows.

Below is the circuit schematic which produces a melody tone whenever the water tank completely filled by water. This circuit also employs transistor switching technique. The advantage of this circuit project is that it uses UM66 musical IC which is capable of producing melody sound when it detects the presence of water and saves water from being wasted.

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Water tank overflow liquid level sensor alarm circuit

Water tank overflow liquid level sensor alarm circuit is a simple electronics project for school students. In the previous articles we had discussed about numeric water level indicator and water level controller circuit ,but those circuits are much complex and are advanced projects for engineering students. The circuit schematic for water tank over flow alarm is shown below. It produces a beep sound when the water tank  is completely filled by water.

The advantage of this project circuit is that it saves water from accidental over flow. The circuit simply consists of a liquid (water) level sensor or water level detector with BC547 transistors. Any electronics hobbyist can implement this circuit at your home or work places at a cheap rate ($0.5). The heart of this water over flow circuit is  the transistor switching part. So this circuit always prevents the wastage of water when you forget to switch OFF the motor pump set after switch ON.

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Gas Leakage Sensor Alarm Circuit Engineering Project using 555 Timer and MQ6 SEN 1327 Gas Sensor Module

In this article we will be discussing about a home security alarm circuit. This is a LPG gas leakage sensor circuit that detects the outflow of LPG gas and alerts the user via audio and visual indications. The heart of this simple engineering project is a gas sensor module SEN 1327. QM 6 gas sensor is used in this SEN 1327 module. The output signal from this gas sensor module is used to drive a 555 timer astable multivibrator. Here 555 timer works as a tone generator, the frequency of tone can be altered by varying the preset VR1.

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UM66 Musical door bell alarm circuit- Melody generator

This circuit is suitable for musical bell in doors, home security alarm systems,  burglar alarms etc. The main part of this alarm circuit is an UM66, which is a melody generator IC.  It is a very small IC that almost looks like a transistor, it has an inbuilt tone and a beat generator. This IC is programmed to generate certain frequencies.When power is turned on, the melody generator is reset and melody begins from the first note.

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