# How to code automatic line-following programs

In the AI era, automatic line-following is a must for most robots. What is the principle of line following? This # How to tells you the answer. You can follow it to learn line-following programs.

Line-following programs keep a robot on the central axis of the line when it moves forward

# Principle of line following #

--The lines don’t have to be black.--The background doesn’t have to be white. --The Quad RGB Sensor on mBot Neo can identify the RGB values of colors. So it can identify most colors. --Long press the button to change the color of the fill light. In low light, you can turn on the fill light to improve the line-following performance.

base_power: Approximate forward speed kp: Adjustment value for left and right wheels during line following left_power: Actual speed of the left wheel right_power: Actual speed of the right wheel

Block explanation:

Multiplying "kp" by the deviation value can reduce the value returned by the Quad RGB Sensor, achieving the goal of fine-tuning the speed.

During line following, when mBot Neo deviates to the left, the deviation value is negative, and when it deviates to the right, the deviation value is positive. Therefore, when the robot deviates to the right, the left wheel needs to slow down to lead the center of the robot back to the center of the line. To achieve this,

During line following, when mBot2 deviates to the left, the deviation value is negative, and when it deviates to the right, the deviation value is positive.
Therefore, when the robot deviates to the right, the left wheel needs to slow down to lead the center of the robot back to the center of the line.
To achieve this, "left_power" needs to increase by subtracting the deviation value (which is negative) from "base_power", making the left wheel speed up and the center of the robot return to the center of the line.
As the deviation value approaches zero, the robot speed approaches "base_power".