Most of the schools and offices have intercoms to communicate with people inside a building or a particular campus. These are just like landline phones but, you do not need an operator, the voice received from one end will be directly transferred to the receiver on the other end.  In this circuit we are going to build a very Simple Intercom Circuit using which you can communicate two ways locally within your house or school. This project brings in the childhood memory of using matchboxes with thread to build a simple telephone.

In this project, we are going to make a Headphone/Audio Amplifier by using self-designed PCB. This project is mainly designed for amplifying the audio signal from the headphones but we can also use it for amplifying the subwoofer or speaker output, just by switching few jumpers.

Building an FM Transmitter and broadcasting our own signals on the air is really a fun project to do.  Especially, with this circuit since it does not require you to wound your own inductor or use a trimmer and spend hours in tuning your circuit to make it work properly.  In this project you will learn How an FM Transmitter Works and how you can build your own with subtle components.

Adding sounds or music to our project will always make it looks cool and sounds much more attractive. Especially if you are using an Arduino and you have lots of pins free, you can easily add sound effects to your project by just investing in an extra SD card module and a normal speaker. In this article I will show you how easy it is to Play music/add sound effects using your Arduino Board.  Thanks to the Arduino community who have developed some libraries to build this in a fast and easy way.

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.

Small Loudspeaker is a fun project to do, you can connect it to your Cellphone or Laptop through a 3.5mm audio jack and can enjoy your own loudspeaker. You can also connect it to any device which has a 3.5 mm audio output, like TV, music player, video games etc. We have used LM386 IC to amplify sound, with a few external components.


Simple Mic audio amplifier can amplify sound that is given from Microphone. This circuit can be used as “Small mic and loudspeaker system” for a small space like a room. This circuit can also be used in many applications like portable music players, intercoms, radio amplifiers, TV sound systems, Ultrasonic drivers etc. It can also be used as sound sensor for microcontrollers. It is inexpensive, low power operated and only need few components to work. This circuit is based on LM386 IC to amplify sound.