Example 10 Using Sensors

What does this code do?

In this code the robot moves forward until it detects a black line.

Functions Used

cmpc( clear_motor_position_counter )

abs( absolute )

gmpc( get_motor_position_counter )

Function Implementation

#!/usr/bin/python3
import os, sys
sys.path.append("/usr/lib")
from kipr import*

L = 3
R = 0
grey_value = 1700

def drive(distance, speed):
    cmpc(L)
    while abs(gmpc(L)) < distance:
        mav(L, speed)
        mav(R, speed)
    mav(L, 0)
    mav(R, 0)
    msleep(20)

def line_stop(speed):
    print("Starting line stop function:")
    while True:
        left_sensor_value = analog(L)
        right_sensor_value = analog(R)

        if left_sensor_value < grey_value or right_sensor_value < grey_value:
            print("Black line detected!")
            print(f"Left sensor (port {L}) value: {left_sensor_value}")
            print(f"Right sensor (port {R}) value: {right_sensor_value}")
            break

        mav(L, speed)
        mav(R, speed)
        msleep(20)  # Add a small delay to prevent too frequent updates

    # Stop the motors
    mav(L, 0)
    mav(R, 0)
    msleep(50)
    print("Stopped at black line!")

def main():
    drive(2000, 1000)  # Drive forward for 2000 ticks with speed 1000
    line_stop(500)  # Continue moving forward until black line is detected

if __name__ == "__main__":
    main()