1 # -*- coding: utf-8 -*-
2 """Run the car and stop if distance to obstacle is < 40cm."""
3 from machine import Pin, PWM
4 from utime import sleep_us, ticks_us
8 SPEED = PWM(Pin(14), freq=1000)
9 BACK = PWM(Pin(15), freq=1000)
14 """Read data from ultrasonic sensor and drive car if no obstacle."""
25 while ECHO.value() == 0:
28 while ECHO.value() == 1:
31 dist = (t2 - t1) / 58.0
32 # drive if obstacle-free
38 sleep_us(nc - ticks_us())
41 if __name__ == "__main__":