The batteries power the motor driver, any servos connected and they also power the Arduino itself. This means you only need one set of batteries to power your project.
The 6V (or 4.8 if using rechargeables) is boosted to 7.5V and fed to the Vin pin on the Arduino. While this is not the most efficient way to power the Arduino, it has the benefit of passing through the Arduino’s power switcher. Therefore there is no risk of current flowing back up the USB port.
Allegro’s dual channel motor driver, the A3906, can provide up to 1A of current per channel. Motor’s can be driven forwards, backward and ‘PWMed’ for speed control. Two pairs of terminal blocks provide a simple method of connection.
Up to three standard RC servos can be connected using the on-board headers. Each signal pin is connected directly to a digital pin on the Arduino, hence the servo library can easily be used.
The on-board on-off switch will disconnect the batteries, saving power when not in use. Pads are also available to connect an external on-off switch. If the Arduino is connected to a USB host, this switch can be used to disable the motors and servos while the Arduino is USB powered.
Digital Input/Output Connection
A single terminal block provides an easy way to connect an input for simple projects. Solder pads are also available for unused Arduino pins.