Security and Alarm

This power interruption alarm circuit will alert you whenever there’s a power failure or an interruption in the mains. In some special conditions it becomes imperative to know whether the mains that powers some important system or circuit is absent. By: Manisha Patel How the power failure alarm works This proposed circuit is connected to […]

This presented refrigerator door open alarm circuit which alerts you after a period of time whenever your refrigerator door is left open. This circuit becomes very handy, because in case the door is left due to carelessness may cause significant increase in the consumption and affect the life of the fridge. Circuit Operation This circuit […]

A simple barcode security lock circuit or barcode scanner circuit is explained in the following article using just a handful of ordinary components such as an op amp, an LDR and an laser light. We all have seen and are familiar with these arrays of thick and thin lines which can be seen printed on […]

In this post I have explained an office call bell network circuit for office complexes which could be used for calling and monitoring office member’s attendance and response from the particular intended office chamber. The idea was requested by Mr. Rajib Banerjee Technical Specifications Need a perfect useable circuit idea for Ringing the Bell as […]

In this post I have explained a simple monostable based power switch ON alarm circuit which automatically switches OFF after an adjustable preset delay. The idea was requested by Mr. Will Boswell. Technical Specifications Hi there, my name is Will Boswell. I am currently working on a project that involves adding an alarm sounder to […]

In this post I have explained a simple laptop anti-theft alarm circuit which can used with any concerned object such as a laptop which needs to be protected, when an intruder tries to approach the unit or makes an attempt to steal it the connected alarm is instantly raised. The idea was requested by one […]