Despite its simplicity, the Battery Low Voltage Alarm circuit has a very important function. It forewarns you of approaching battery failure so that you may run to the store and get replacement cells before your equipment stops functioning entirely. Because of its compact size and low current need, it may be integrated into the devices […]
Security and Alarm
How to Make a Barcode Security Lock 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 […]
Make this Simple Refrigerator Door Open Alarm Circuit
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 […]
Simple Ultrasonic Sound Sensor Alarm Circuit using Opamp
This article discusses a simple ultrasonic sound sensor alarm circuit which may be appropriately set for detecting sound pressures well above the normal human listening capacity, that may range from 20 kHz and over. Ultrasonic Concept Ultrasound or ultrasonic sound waves was probably invented even before humans existed on this planet by a few of […]
5 Simple Alarm Circuits for Protecting your Home/Office from Theft
The following article discusses a few very simple intrusion detector circuits, or ant-theft alarms. The presented designs are easy to build yet extremely effective with the functions. How the Circuits Works An intruder alarm basically consists of a sensor and a trigger stages, which work together to produce the required detection. The sensor detects the presence […]
Anti Spy RF Detector Circuit – Wireless Bug Detector
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 […]