Category Archives: Communication



Home Telephone Call Recorder

This is the circuit connection of home telephone call recorder that uses very few components. In order to understand its working, we must first have the basic knowledge of standard telephone wiring and a stereo plug. In some countries, landline telephones primarily use RJ11 wiring, which has two wires—tip and ring. While tip is the… Read More »

Infrared (IR) Cordless Headphone

This is the schematic diagram of Infrared (IR) cordless headphone. Maybe it also can be called “wireless headphone”, but it use infrared as sound signal carrier. It use a pair of circuit diagrams that are IR transmitter and IR reveiver. Using this low-cost project one can reproduce audio from TV or other electronic devices without… Read More »

Remote Control Tester

Here is the remote control tester circuit. This circuit is really a simple and easy tester for verifying the basic operations of an infrared remote control unit. It is low-cost and very easy to construct. The tester is designed around infrared receiver module TSOP1738. Operation of the remote control is identified by a tone from… Read More »

Long Range/Distance Infrared Transmitter

Here the long range/distance Infrared transmitter circuit, give you extra power for your Infrared transmitter. The majority of the IR remotes do the job reliably within a range of 5 metres. The circuit complexity increases in case you design the IR transmitter for good operation more than a extended distance, for example, 10 metres. To… Read More »

Low-Cost and Simple Intercom

This is a low-cost and simple intercom circuit design. Some intercom circuits is build by applying integrated circuits. The circuit described right here utilizes 3 certainly transistors which easy to find on the electronic store. Even a newbie can assemble it on a piece of veroboard without difficulty. The circuit consists of a 3-stage resistor-capacitor… Read More »

Toy Car Remote Control

The circuit, consisting of an infrared transmitter-receiver pair, utilizes IR beam transmission to switch the toy car “on” or “off’, yeah… it will be only switching on and switching off, you may modify this circuit to make the toy car to turn left or right. To operate the toy car, you have to hold the… Read More »