Raspberry Pi and a Simple Robot

Using a pair of DC motors and connecting them to two wheels can be the basics of a simple robot. Once you add a single board computer to this basis structure, you can do almost whatever your like with your robot. However, making a robot do more than simply run around requires many mechanical appendages that may prove difficult to get unless you have access to a workshop or you are proficient with 3D printing.

To simplify things for beginners, the robot chassis from Adafruit is a versatile kit. With this simple robot kit and a single board computer such as the Raspberry Pi or RBPi, you can start your first lessons in robotics.

As the kit is for beginners just starting with their first robot, there are no sensors. A Motor HAT (Hardware Attached on Top) controls two motors connected to two wheels on a chassis. The front of the chassis has a swivel castor, which makes it stable. The RBPi mounts on the chassis and a battery supplies the necessary power for the SBC and the motors.

Once you are familiar with generating a set of instructions in Python to make the robot move the way you want it to, you can start adding sensors to the kit. For example, simply adding a camera will allow the robot to see where it is going. Adding an ultrasonic range finder will allow the robot to avoid bumping into obstacles in its path.

The Mini Rover Robot Chassis Kit from Adafruit includes almost everything one needs to build a functional robot. It has an anodized aluminum chassis, two mini DC motors, two motor wheels, a front castor wheel, and a top plate with standoffs for mounting the electronics.

It is convenient to use the latest RBPi models such as the Model 2, B+, or A+, as these have suitable mounting holes that allow easy attachment to the robot chassis. Although it is also possible to use the RBPi Zero, its small size makes it unsuitable to mount the motor HAT securely.

The Motor HAT can drive DC and stepper motors from the RBPi and is suitable for small robot projects. The brass standoffs help to hold the Motor HAT securely to the RBPi. Power comes from two sources. One 4x AA battery pack supplies the motors. Another small USB battery pack powers the RBPi. The RBPi also requires a Wi-Fi dongle to keep it connected to the computer and to control the RBPi robot.

Your RBPi must be running the latest version of the Operating System – Raspbian Jessie. If you do not have this, allow the RBPi to access the Internet and download the necessary software.

The Motor HAT library examples included provide adequate software for this project to start. For example, you can use the example scripts provided to make the robot move forward, backward or to turn in different directions. Preferably, place the robot on level ground, where there are no obstacles. As the robot has no sensors, it can hit something or easily fall off the edge of a table.