Parallel-Port Controller Using MATLAB
Many projects have been published in EFY on how to program a PC’s parallel port using C, C++ and Visual Basic. Here we attempt...
Stereo Brick Amplifier
If you are looking for a compact and inexpensive add-on audio amplifier for your digital surround sound system or computer, then this subwoofer amplifier...
Ball Speed Checker
This ball speed checker circuit measures the speed of a cricket ball based on the time taken by the ball to travel the distance...
Four Stage FM Transmitter
This four stage FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier built around transistor...
Three Phase Appliance Protector
Many of our costly appliances require three-phase AC supply for operation. Failure of any of the phases makes the appliance prone to erratic functioning...
Power Resumption Alarm and Low Voltage Protector
The low voltage protector circuit described here protects your electrical appliances like AC motors from damage due to low voltage at power-on. It remains...
PC Timer
Primarily intended for installation into a desktop PC, this versatile PC timer with adjustable time output provides controlled ‘on’ time for PC peripherals like...
Multipurpose Power Pulser
The idea behind this multipurpose power pulser is very simple. As shown in the circuit (Fig. 1), it uses a low-frequency oscillator to drive...
Password-Protected Bluetooth Remote Control
This password protected bluetooth based remote control operating at 2.4GHz frequency can be used to control robots, home appliances, machines, etc. Here we have...
Simple 8-Bit Computer for Learning
This project helps you build a 8-Bit computer while also providing an insight into the working of an MPU & its construction mechanism.
Computers take...
DC Motor Starter Using Arduino Uno Board
Motor starter reduces the load, torque and current surge of a motor during startup. On starting, the motor takes more than five times the...
Arduino Ping Pong Game
Ping Pong was the first ever video game that reached mass market. For the first time in history, the concept of a “video game”...
Web Server using Raspberry Pi 2
Raspberry Pi is a small credit-card sized computer capable of performing various functionalities. It is heavily used in surveillance systems, military applications, etc. Several...
High Fidelity FM Transmitter
FM broadcasting is radio broadcasting using frequency modulation technology. In order to attain high-fidelity broadcast of music and speech, all audio frequencies up to...
PC Based Stepper Motor Controller
This PC based stepper motor controller is perhaps the cheapest, smallest and simplest. A pair of H-bridges with a software program written in ‘C++’...
Multicell Charger
Using this multicell charger, you can safely charge up to two pieces of Ni-Cd cells or Ni-MH cells. The circuit is compact, inexpensive and...
Voltage Based Controller For Switches
Here’s a simple voltage based controller circuit for controlling four switches from a distance through just a pair of wires.
Voltage based controller circuit
In the...
Low-Cost Battery Charger
Here is a very simple and low-cost charger for 12V, 7Ah lead-acid batteries. It can also be used for powering automobile engines and emergency lighting systems.