line follow

line follow.py

import machine
import utime
from motor_driver import *             # import motor_driver library
import _thread

Trig = machine.Pin(6,machine.Pin.OUT)  # Connect Trig pin to pin 6 and set to OUTPUT
Echo = machine.Pin(7,machine.Pin.IN)   # Connect Echo pin to pin 7 and set to INPUT

line = machine.ADC(26)                 # Set pin 26 as analog INPUT

motor = motor_driver(4,5,2,3)          # M1A = 4, M1B = 5, M2A = 2, M2B = 3

global us_trig                         # Declare global variable
us_trig = False                        # set false as default value

def read_ultrasonic():                 # read ultrasonic function
    Trig.value(0)
    utime.sleep_us(2)
    Trig.value(1)
    utime.sleep_us(10)
    Trig.value(0)
    
    while Echo.value() == 0:
        pulse_start = utime.ticks_us()

    while Echo.value() == 1:
        pulse_end = utime.ticks_us()
        
    pulse_duration = pulse_end - pulse_start
    distance = pulse_duration//58
    return distance 

def read_line_sensor():               # read line sensor function
    return line.read_u16()
    
def us_reader_thread():               # read ultrasonic thread
    global us_trig
    while True:
        if read_ultrasonic() < 10:    # if ultrasonic distance less than 10
            us_trig = True            # set global variable to True
            
_thread.start_new_thread(us_reader_thread, ())   # start read ultrasonic thread


while True:
    line_value = read_line_sensor()
    if us_trig == True:              # if ultrasonic triggered
        motor.brake()                # brake the motor
        utime.sleep_ms(500)          # sleep 500ms
        global us_trig 
        us_trig = False              # set global variable to False
    else:
        if line_value > 60000:    # All line
            motor.speed(60,60)
        elif line_value > 40000:  # S5,S4+S5
            motor.speed(60,10)
        elif line_value > 34000:  # S4,S3+S4
            motor.speed(60,30)
        elif line_value > 30000:  # S3
            motor.speed(60,60)
        elif line_value > 22000:  # S2,S3,+S2
            motor.speed(30,60)
        elif line_value > 10000:  # S1,S2+S1
            motor.speed(10,60)
        elif line_value > 200:    # No line
            motor.speed(30,30)