The first prototype with working Arduino, Adafruit motor shield, XBee, XBee adapter, motor power pack and 9V Arduino power, plus the Arduino sketch and Windows controlling program. The first try was buggy but working. Update: It turns out that the rechargeable power pack (from a swiffer) used to run the 2 DC motors was overheating the H-bridge on the motor shield. After switching to 4 AA batteries everything ran smoothly and we were able to drive it around the house. But eventually we burnt out the motor shield.