The goal of this project was to make a robot that could follow a colored line across a table using a color sensor and PID control.
Modeling
The chassis of the follower could be modeled to hold the components. Two stepper motors were used, alongside their respective L298N motor drivers, their battery, a raspberry pi, and the color sensor. 3D-printed wheels were created to press-fit the stepper motors. An LED was later added to help aid the color sensor for a more constant light environment.
Code
The stepper motor code had to be slightly rewritten to handle multiple motors, using multi-threading. This would allow us to run both motors at different speeds or directions at the same time, for turning purposes. The number of steps for each motor was used as the PID controller output. The robot's color sensor would detect what color was directly underneath it, and then calculate the error away from an accepted color value. Doing this, the robot could steer towards or away from the line to follow the left side and cross intersections. The controller also allowed for multiple colors to be detected, and therefore multiple tape lines to be followed.
Obstacles
Some small obstacles arose when wiring the robot; for example at one point a motor driver positive lead had come out of the screw terminal and self-soldered itself to a bottom pin, completing a circuit and exploding the driver. Calibrating the colors also came with some difficulties in the changing light conditions, so a normalization method using the "clear" channel was attempted before switching to using the LED.
