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Light Alarm with Timer 555

Here is the simple and low cost light alarm circuit built using timer IC 555 as the sound generator and a LDR to sense the environment light. This alarm is activated when the light beam on the LDR photocell is interrupted (You can use the light of a flashlight bulb which will make you a… Read More »

Car Audio System Anti Theft Security

This is the circuit diagram of car audio system anti theft security which can be effectively used to protect and secure your expensive car audio system from stealing. This simple circuit designed based on popular CMOS NAND chip CD4093,. When the circuit is switched on via switch S1, the indicator LED1 will glow and the… Read More »

Ultrasonic Distance Detector / Sonar Ranging System

This is the ultrasonic distance detector or sonar ranging system which can be used for general purpose. There are kit version available on the market, but of course the price is 3x more expensive than if you build your own sonar ranging system. Some application may use this circuit such as robot applications, body height… Read More »