In this project, we will make a 4-Channel Relay Driver Circuit for relay based applications. In this circuit, we have designed an isolated PCB for 4 relays. By using this Relay Board, we can operate 4 AC appliances at a time. We have put a three pin screw terminal blocks (NC, Nuteral, NO) for connecting appliances. Here we have provided PCB layout, circuit diagram and gerber files, so that you can build or directly order this Relay Driver Module.


Stun gun is a device which generates high voltage at it’s output by taking low voltage as input. Concept of this device is based on High volt inverter. Here we are building this Stun Gun circuit on PCB. Stun Gun can be dangerous and can cause serious damage if not used properly, we take no RESPONSIBILITY for any resulting actions. This stun gun circuit can also works in mosquito killer racket or insect zapper.


We often see voltage fluctuations in electricity supply at our home, which may cause malfunction in our home AC appliances. Today we are building a low cost High and Low Voltage Protection Circuit, which will cut off the power supply to the appliances in case of High or Low voltage. It will also show a alert message on 16x2 LCD. In this project, we have used PIC Microcontroller to read and compare the input voltage to the reference voltage and take the action accordingly.

In this project we are going to build a Digital Voltmeter without using any microcontroller. Here we are using a very popular IC for voltage measurement namely ICL7107/CS7107. Using ICL7107, we can build accurate and very low cost voltmeter. ICL7107 is a 3.5 digit analog to digital converter (ADC) which consumes very low power. The IC has internal circuit for driving four seven segment display to display the measured voltage. It also has a clock circuit and a reference voltage source.

In this project, we are going to use a PIC microcontroller to remotely control few AC loads by just using an IR remote.

In this project, we are going to make a Voice Modulator Circuit, by using self-designed PCB. In this project, we have designed a PCB using EASYEDA online PCB simulator and designer. This is a fun project, mainly designed for changing or altering the voice. Generally, when we speak in a MIC we hear same voice. But in this project when we speak in MIC, we will hear a little bit different voice something like a robot is speaking. This can be used for doing prank or fun with your friends or can be used as a voice of your Robot.

Smoke Detectors are very useful in detecting smoke or fire in buildings, and so are the important safety parameters. In this DIY session, we are going to build a Smoke Detector Circuit which not only sense the smoke in the air but also reads and displays the level of Smoke in the Air in PPM (parts per million). This circuit triggers the Buzzer when Smoke level becomes higher than 1000 ppm, this threshold value can be changed in the Code according to the requirement.

EasyEDA is a Cloud based free online service to design Circuit Schematics, simulate circuits, convert schematics into PCB Layout and manufacture PCBs for end users and industries. This all can be done at one place with EasyEDA online tool.

In this project I am going to share a LED Scroll Bar as shown in the above picture. Ten LED strips can flash in different effects by using an Arduino board. 


EasyEDA is a Online PCB design and Simulation Tool. We have already covered this tool in detail in this article EasyEDA for Electronic Circuit Design. Today, we will learn ‘How to use EasyEDA’ by designing and simulating the Simple 100 watt Inverter Circuit, with the help of Easy EDA.