Security and Alarm

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 […]

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 […]

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 […]

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 […]

The door security alarm circuit discussed in this article alerts the user whenever the door fitted with the circuit is opened or closed or even moved from its original locked position. Using a Reed Relay and Magnet for the Triggering The idea utilizes the very basic reed relay and magnet concept across the door and […]