Ludus Protoshield Hookup Guide
This Tutorial is Retired!
This tutorial covers concepts or technologies that are no longer current. It's still here for you to read and enjoy, but may not be as useful as our newest tutorials.
View the updated tutorial: Wireless Motor Driver Shield Hookup Guide
Nick Poole 
Going Wireless
If you have the Ludus ProtoShield Wireless, you can free your project from its USB tether! Do do this, you'll need a pair of XBee radio modules and an XBee Explorer USB. Even if you're not familiar with XBee, you should be able to run the example code wirelessly as the radio modules should be configured properly by default. For an introduction to XBee, check out this SparkFun tutorial for getting started with XBees. There's a lot more you can do with XBee than what we'll cover here.
The first step is to plug an XBee radio into the ProtoShield. The silkscreen on the board shows which orientation it should go. Make sure that the slide switch marked "HW_Ser" and "SW_Ser" is set to "HW_Ser". This will connect the XBee radio to the hardware serial lines of the Arduino. Next, plug your XBee Explorer into the USB port on your computer, and open the serial terminal program that you were using in the Simple Motor Control section. Open the COM port for the XBee Explorer and switch the Arduino on.
The example code should now work exactly as it did before, only this time, your serial commands are being sent over the air! What's happening is that the XBee radio is acting like a wireless serial tunnel. As far as the Arduino knows, there's a USB cable hooked up to the serial line.