This is a motor shield for Arduino which will control two DC motors. Based on the L298 H-bridge, the Ardumoto drives up to 2 amps per channel.
Great for any mobile, rover or robot / robotics project that needs to use DC motors.
You can probably use this with a Mega2560, but technically you'd need to jumper it into place as the shield is not a compatible fit.
The board obtains its power from the same Vin line as the Arduino board. It includes blue and yellow LEDs to indicate active direction, and all the driver lines are diode protected from back EMF.
The latest version of the shield supports 3.3 or 5v logic and a separate, more robust VIN connection. The PWM input has moved to pin 3.
Control for motor attached to OUT1/2 is connected to digital line 12 (direction A) and digital line 3 (PWM A). Control for motor attached to OUT3/4 is connected to digital line 13 (direction B) and digital line 11 (PWM B).
Note: The VIN connection is tied directly to the VIN on the Arduino, so make sure not to apply power to both.