AC Powered PIR Light


A Simple design of PIR Light using Tranformerless Power Supply and Triac for driving the load. Too compact and can be enclosed in a small case. The light turns on when the PIR sensor detects human movement and turns off after the preset time. Re triggers in another movement. Its range is 30 cm to 10 meters and time delay, 30 seconds to 3 minutes both can be adjusted using the presets in the PIR sensor Module.

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Ultrasonic Pest Chaser


Ultrasonic Pest Chaser

Here is an efficient Electronic Pest Repellent to chase Pests from home. It emits Ultrasound in the frequency 9 to 96 kHz which can be set for each Pest. Human can’t here the Ultrasound since it is out of human sound detection range. But most animals can hear Ultrasound.The circuit emits powerful Ultrasound to repel pests.

Mosquitoes are usually repelled between 20 and 40 kHz, Rats around 56 kHz, Cockroaches around 36 kHz and Flies around 30 kHz. Out put power of the circuit is 2 watts 1.3 dB. It can repel Mosquitoes, Rats, Cockroaches, Wall Lizards , House flies etc from home. Made and found effective.


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How to connect Relay with NPN and PNP transistors


Transistor is used to drive relay to connect AC loads. For efficient working, it is important to connect the relay correctly in NPN and PNP transistors. See the way of connection. Continue reading “How to connect Relay with NPN and PNP transistors”

How to Convert SMPS to Bench Power supply cum charger



Don’t throw away the SMPS power supply when the Computer damges. SMPS is a high current device that gives different regulated voltages from the output wires. It has numerous wires to give different voltages . So you can make a good Multi voltage power supply for the Projects or use as battery charger for different types of batteries. It has total isolation from Mains and output is safe DC.
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