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Security and Alarm

PIR Burglar Alarm Circuit

Last Updated on November 18, 2025 by Swagatam 27 Comments

PIR alarm block

The PIR burglar alarm explained here will detect a human intruder within the stipulated range and sound an alarm. Thus, the system could be effectively use for detecting trespassing, theft, intrusion, burglars, or any form of unlawful entry inside a restricted area or zone. Basic Principle The operating principle of the proposed burglar alarm circuit […]

Filed Under: Security and Alarm Tagged With: Alarm, Burglar, PIR

Impact Collision Switch Sensor Module and Circuit Diagram

Last Updated on April 28, 2025 by Swagatam 4 Comments

Here we are going to learn about a very interesting small sensor called the Impact Collision Switch Sensor Module. This module is super simple but very useful especially when we want to detect a shock, collision, hit or a sudden tap on a surface. Now let us go step-by-step to understand everything about it. What […]

Filed Under: Security and Alarm, Sensors and Detectors Tagged With: Collision, Impact, Module, Sensor, Switch

3 Accurate Infrared Intruder Alarm Circuits using Photodiodes

Last Updated on January 19, 2025 by Swagatam 31 Comments

IR transmitter

In this post I have explained 3 simple yet accurate infrared intruder alarm circuits using an infrared transmitter and an infrared receiver module. The transmitter and the receiver photo diodes used in the two modules are aligned in line at a distance of around 2 meters within the restricted area. When a burglar tries to […]

Filed Under: Security and Alarm Tagged With: Accurate, Alarm, Circuits, Infrared, Intruder, Photodiodes

2 Tone Ringtone Generator Circuit

Last Updated on January 19, 2025 by Swagatam 4 Comments

twotonealarmcircuitwithspeaker

The IC LS1240A from SGS Thompson is specifically designed for generating a 2 tone ringtone generator circuit. Thus the IC specifically becomes suitable for landline telephones for producing the ringtones when a call is received. However with little modifications the IC can be easily utilized for normal applications, in circuits where a double tone alarm […]

Filed Under: Security and Alarm Tagged With: Generator, Ringtone, Tone

2 Simple Earth Leakage Circuit Breaker (ELCB) Explained

Last Updated on January 19, 2025 by Swagatam 36 Comments

The discussed Earth leakage circuit breaker diagrams will monitor the leakage current level of the earthing line of your house electrical sockets and will trip the appliances as soon a fault is detected. Here I have explained 2 designs, first using transistors only and the second using IC LM324. Introduction If anything goes wrong with […]

Filed Under: Security and Alarm Tagged With: Breaker, Earth, ELCB, Explained, Leakage, Simple

7 Interesting IC 555 Siren and Alarm Circuits

Last Updated on December 26, 2024 by Swagatam 45 Comments

whooper siren compressed

In this post I have explained how to use IC 555 to create 7 interesting siren and alarm sound effect generator circuits. The versatile astable multivbrator configuration of IC 555 allows us to implement it for making various types of sirens and alarm circuits. This becomes possible because an astable is basically a waveform generator, […]

Filed Under: Security and Alarm Tagged With: 555, Alarm, Circuits, Interesting, Siren

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