Hardware and software requirements
Let's take a look at the components required for this robot. The first thing that we will need is the robot chassis itself. You have several options for this part, but I recommend the DFRobot MiniQ 2 wheels chassis. It is a tiny robot with two motors and two wheels and is compatible with most Arduino boards. I chose this robot for its low price point and because it is really easy to use with Arduino. However, you can choose any robot chassis that has two wheels and that is compatible with Arduino boards.
You will then require several Arduino boards to interface with the robot. The first board is the usual Arduino Uno board, which will serve as the brain of the robot. You will also need a DFRobot motor shield to control the two wheels of the robot from Arduino. Finally, you will need an Arduino XBee shield in order to mount an XBee Series 1 module. This will be used to control the robot remotely.
After that, you will need an URM37 Ultrasonic Sensor...