Note
The Pi Plate is necessary only if you are going to build your own circuitry (instead of an off-the-shelf robot kit) that drives the robot.
We will make use of the Pi Plate from Adafruit Industries. The Pi Plate is stackable and an add-on hardware for the Raspberry Pi. The Pi Plate is like a breadboard/perforated prototyping board and enables prototyping using the Raspberry Pi platform. We will assemble the headers on the board.
The Pi Plate is available from Adafruit Industries (www.adafruit.com). It costs 15.95 USD. This stackable add-on hardware is useful because the sensors and actuators can be connected using the screw-in terminals. This will avoid any loose connections to your Raspberry Pi while the robot is in motion.