Entry Alarm Circuit

This is an Infrared based Broken beam alarm to protect doors and entry passages. It gives a loud alarm when somebody crosses the Invisible Infrared barrier.....

Motion Detector Alarm Circuit

This motion detector alarm can detect a moving person from a distance of 1 meter. It uses a dual IR Transmitter-Receiver module HOA1405. When the sensor de.....

Panic Alarm Circuit

This Alarm will help you with its loud Police siren to abort the attempt of intrusion. With a single clap, the circuit generates the alarm for three minutes and...

Shadow Alarm Circuit

This shadow alarm circuit can sense a moving shadow in a confined area. It can be used to protect things from theft. When somebody approaches the unit, it will ...

Ultrasonic Beam Barrier Circuit

This circuit generates inaudible ultrasound to make a barrier across the entry. At the moment the circuit detects a break in the sound barrier, it generates a l...

Mobile Scanner Circuit

A device to locate the mobile phone. It emits intermittent flashes and beeps to indicate the presence of an active mobile phone. The circuit becomes active even...

Laser Door Alarm Circuit

This laser door alarm is based on the interruption of Laser beam. A low cost Laser pointer is used as the source of light beam. When somebody breaks the la.....

Fire Sensor Circuit

This fire sensor circuit exploits the temperature sensing property of an ordinary signal diode IN 34 to detect heat from fire. At the moment it senses heat, a l...

Electronic Locker Guard

Protect your Locker or Briefcase from theft using this pocket sized gadget. It gives a loud police siren to catch attention. The circuit uses a single IC a.....

Electronic Pest Repellent Circuit

There are many ultrasonic pest repellent devices available on the market but a major drawback is that their power output is low and their effectiveness suf.....

Smoke Detector Circuit

It relies on the smoke that is produced in the event of a fire and passes between a bulb and an LDR, the amount of light falling on the LDR decreases. This type...

Fire Alarm Circuit

In this fire alarm circuit project, a thermistor works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. At normal.....

Burglar Alarm System Project

This burglar alarm system circuit is using a infrared proximity detector that triggers an alarm when the rays falling on its sensor are interrupted. It is diffe...

Dog Repellent Circuit

The electronic dog repellent circuit diagram below is a high output ultrasonic transmitter which is primarily intended to act as a dog and cat repeller, wh.....

Luggage Bike Security Alarm Circuit

This luggage or bike alarm can be used while travelling by trains or bus and we generally lock our luggage using a chain-and-lock arrangement. But, still w.....

Simple Code Lock Circuit

This simple code lock circuit described here is of an electronic combination lock for daily use. It responds only to the roght sequence of four digits that are ...

electronic door buzzer circuit schematic

This electronic door buzzer circuit schematic has a very simple function and is very easy to build. This door buzzer circuit use a LF351 operational amplifier a...

Simple Electronic bell circuit using transistors

A very simple and useful electronic bell circuit can be made using this schematic circuit diagram. This electronic bell circuit can be used as an doorbell or ev...

Simple combination lock

This experiment may be built using only one 8-position DIP switch, but the concept is easier to understand if two switch assemblies are used. The idea is, one s...

Please help with ultrasonic animal repeller circuit

HI FRIENDS, I HAVE A ANIMAL REPELLER CIRCUIT CIRCUIT DIAGRAM AS SHOWN: I HAVE WRKED ON THIS BUT NOT WORKING AS PREFERRED CAN U PLEASE CHECK THIS ONE.....