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 […]
Security and Alarm
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 […]
Simple Shop Shutter Guard Circuit to Safeguard your Shop from Theft
The shop shutter guard circuit discussed here guards your shop when its shutter is closed i.e., at night if an intruder tries to break the shutter, the piezo senses the vibration and the relay is fired to which a 230 volt bulb can be connected which makes the intruder think that someone’s inside…..but he doesn’t […]
3 Smart Laser Alarm Protection Circuits
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 […]