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Security and Alarm

Anti Spy RF Detector Circuit – Wireless Bug Detector

Last Updated on January 2, 2024 by Swagatam 100 Comments

ACFieldDetector

A anti-spy or bug detector circuit is a device that detects hidden wireless electronic devices such as wireless microphones, spy cameras, Wi-Fi devices, GPS trackers or any gadget that emits some kind of radio frequency (RF). The proposed design can be specifically used as: Overview Also called anti spy RF sniffer, these are usually used […]

Filed Under: Security and Alarm, Sensors and Detectors Tagged With: Anti, Detector, RF, Wireless

3 Smart Laser Alarm Protection Circuits

Last Updated on January 2, 2024 by Swagatam 144 Comments

alarm

In this post I have explained the making of 3 simple yet effective smart laser alarm protection circuit using the IC 555, for securing a specified restricted zone from human interventions. The idea was requested by Mr. Collins. Circuit Objectives and Requirements 1) The Design Parts List IC 555Pinouts Circuit Operation The proposed smart yet […]

Filed Under: Security and Alarm Tagged With: Alarm, Circuits, Laser, Protection, Smart

Mains High Low Voltage Protection Circuit with Delay Monitor

Last Updated on May 25, 2026 by Swagatam 167 Comments

opamp2BV

In this post I have explained an upgraded version of my previous mains 220V/120V high-low voltage cut off protection circuit which now includes a delayed restoration of power for the load with 3 LED power status indicators. The idea was requested by one of the dedicated members of this website. Circuit Objectives and Requirements Main […]

Filed Under: Security and Alarm Tagged With: Delay, High, Mains, Monitor, Protection, Voltage

Intruder Position Indicator Security Circuit

Last Updated on January 4, 2024 by Swagatam 17 Comments

In this post I have explained an LED based intruder position indicator circuit which will indicate the position of the burglar throughout the secured corridor as the person tries to sneak past the area.The idea was requested by Mr. Michael. Circuit Objectives and Requirements Your articles are nice, well done. sir can this, close and […]

Filed Under: Security and Alarm Tagged With: Indicator, Intruder, Position, Security

SMS Based Laser Security Circuit

Last Updated on September 11, 2019 by Swagatam 36 Comments

blockdiagram

In this post, I will show how to construct a laser security circuit which can send SMS alert to owner of the property or anyone else and activate loud alarm to deter the crook, which can be interfaced via relay. We always fear about crooks especially when we leave our property alone, this where security […]

Filed Under: Security and Alarm Tagged With: Based, Laser, Security, SMS

RFID Security Lock Circuit – Full Program Code and Testing Details

Last Updated on August 9, 2019 by Swagatam 6 Comments

P 20161027 182018 1 p 1

In this article we will see how an Arduino based RFID reader circuit could be used for controlling a relay, which in turn could be used in security door lock applications. Overview If you haven’t yet checked the previous RFID article, please go ahead check it out, it covered the basics of RFID technology. We […]

Filed Under: Security and Alarm Tagged With: Code, Full, Lock, Program, RFID, Security

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