An H-Bridge module/shield allows a micro controller like Arduino to operate a motor in two directions (clockwise and anticlockwise). An H-Bridge fits many applications like a mini car. Usually a H-Bridge contains an IC like L293D. In this instructable I'm going to show you how to make a H-bridge shield for Arduino which can control up to 2 motors using only NPN transistors. It is not only fun to make but, is also cheaper than buying commercial H-bridge shields.
Components needed to make the shield-
Hey, if you want a fun project for determining if your transistor is NPN or PNP please refer to my 'The Transistor Testenator' instructable.
You, of course, need to have an Arduino and motors. A breadboard would also help as it allows you to prototype the circuit before soldering it permanently on to the perf board.