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Security and Alarm

Earthquake Sensor Circuit [Seismic Sensor]

Last Updated on September 30, 2021 by Swagatam 43 Comments

earthquakesensorcircuitsiesmicsensorcircuit

The article shows an earthquake sensor circuit idea which incorporates an innovative way of detecting the minutest of shocks caused by a possible earthquake tremor. The circuit is so sensitive that it is able to detect tremor of 4 on the Richter scale, yet remains unaffected to loud sounds or irrelevant bangs or noises. Introduction […]

Filed Under: Security and Alarm Tagged With: Earthquake, Seismic, Sensor

Detecting Static Human with PIR

Last Updated on April 1, 2021 by Swagatam 26 Comments

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In this post I have explained a method which can be probably used for enhancing a passive infrared sensor ability to detect even a static or stationery human presence. This feature is normally not possible with the conventional PIR sensors. How PIR Detect Human Presence I have already discussed many PIR based motion detector applications […]

Filed Under: Security and Alarm Tagged With: Detecting, Human, PIR, Static

Laser Diode Driver Circuit

Last Updated on October 16, 2020 by Swagatam 40 Comments

ddl laser driver and current and voltage measuring circiut 001

The current controlled circuit of a laser pointer power supply explained in the following post was requested by Mr. Steven Chiverton (stevenchiverton@hotmail.com), who himself is an intense electronic hobbyist and researcher. Technical Specifications Dear swagatam, I’m emailing you to ask you for your expertise, and you being one of India’s finest electronics engineers I thought you be […]

Filed Under: Security and Alarm Tagged With: Diode, Driver, Laser

Ultrasonic Fire Alarm Circuit using Air Turbulence Detection

Last Updated on October 3, 2020 by Swagatam 8 Comments

ultrasonic fire circuit min 1

The simple ultrasonic fire alarm circuit I have explained below detects a fire hazard situation by picking up the variations in the surrounding air waves, or the air turbulence. The high sensitivity of the circuit ensures that even the slightest of air turbulence created by a temperature difference or fire is quickly detected and an […]

Filed Under: Security and Alarm Tagged With: Alarm, Detection, Fire, Turbulence, Ultrasonic

Loop-Alarm Circuits – Closed-Loop, Parallel-Loop, Series/Parallel-Loop

Last Updated on September 25, 2020 by Swagatam 6 Comments

silent alarm

In this article I have explained a few simple loop based security alarm circuits, categorized under closed loop, parallel loop, and series/parallel loop. All these designs could be customized and used for a variety of security alarm applications. Overview In a loop alarm circuit, more than one sensor is used, each one wired with a […]

Filed Under: Security and Alarm Tagged With: Alarm, Circuits, Closed, Loop, Parallel, Series

Infrared Remote Controlled Door Lock Circuit

Last Updated on June 1, 2020 by Swagatam 22 Comments

IRdoorlockcircuit

In this article I have explained about a simple infrared remote controlled door lock circuit which can be used for securely locking doors through unique foolproof IR frequencies. The proposed infrared remote controlled door lock circuit can be used for locking your main door, gate, garage door, shop or any entrance which may need a […]

Filed Under: Remote Control Circuits, Security and Alarm Tagged With: Controlled, Door, Infrared, Lock, Remote

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