#!/usr/bin/env python3

from machine import Pin, PWM, time_pulse_us
import time

TRIG = 17
ECHO = 19

def setup():
    global pins
    global p_Trig, p_Echo
    
    p_Trig = Pin(TRIG, Pin.OUT)
    p_ECHO = Pin(ECHO, Pin.IN)

    p_Trig = PWM(Pin(TRIG))
    p_Trig.freq(50)
    p_Trig.duty_u16(32000)

    time_pulse_us(ECHO, 1, 5000000)
    p_Echo = Pin(ECHO, Pin.IN, Pin.PULL_UP)


def distance():
    x = time_pulse_us(ECHO, 11) * 0.01
    return x

def loop():
    while True:
        dis = distance()
        print (dis, 'cm')
        time.sleep(0.3)

# Main Routine

setup()
while(1):
    loop()