This is a full-featured motor shield for Arduino, which is able to power many simple to medium-complexity projects.

Features:

•     2 connections for 5V 'hobby' servos connected to the Arduino's high-resolution dedicated timer
•     4 H-Bridges: L293D chipset provides 0.6A per bridge (1.2A peak) with thermal shutdown protection, internal kickback protection diodes. Can run motors on 4.5VDC to 25VDC.
•     Up to 4 bi-directional DC motors with individual 8-bit speed selection (so, about 0.5% resolution)
•     Up to 2 stepper motors (unipolar or bipolar) with single coil, double coil or interleaved stepping.
•     Pull down resistors keep motors disabled during power-up
•     Big terminal block connectors to easily hook up wires (18-26AWG) and power
•     Arduino reset button brought up top
•     2-pin terminal block and jumper to connect external power, for separate logic/motor supplies (remove the jumper to use different power supplies for Arduino and motors)
•     Tested compatible with Arduino Mega 2560 and UNO