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KNOCK ALARM

This circuit (Fig. 1), used in conjunction with a thin piezoelectric plate,senses the vibration generated on knocking a surface (such as a door or...

Night Lamps

Here are two night lamp circuits using LEDs. One could be used as a night-vision clock and the other as a TV lamp. Both...

Musical Water Shower

Won’t it be nice to have music playing in the background all the while when you take a shower? This simple circuit does the...

Traffic Baton

In small towns, there are no traffic lights and the police regulate the traffic with hand signals. Since their hand signals may not be...

Traffic Controller

This simple traffic controller can be used to teach children rudiments of traffic rules. The circuit (shown in Fig. 1) uses readily available components. It...

Hot-Water-Ready Alarm

Electric kettles turn off automatically when water has boiled. What if the boiler beeps to alert you when your water has boiled? The tripping...

Peak Hour Timer

Electrical appliances like refrigerators and air-conditioners consume heavy current if the line voltage drops during the peak hours between 6 pm and 9 pm....

DIY Touch Alarm

This is a new type of touch alarm that uses an RF oscillator at its input. One special feature of this touch alarm is...

DIY Electronic Heart

With this electronic heart glowing on and off, you are sure to steal the heart of that special someone. The circuit uses an NE555...

CAR ANTI-THEFT GUARD

Here is an easy-to-build car anti-theft guard. The circuit, shown in Fig. 1, is simple and easy to understand. When key-operated switch S2 of...