# Range Sensor
from machine import Pin, PWM, time_pulse_us
from time import sleep_ms

TRIG = 17
ECHO = 19

def setup():
    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_ns(1000)
    p_Echo = Pin(ECHO, Pin.IN, Pin.PULL_UP)

def distance():
    mm = time_pulse_us(ECHO, 11) * 0.1715
    return mm

def loop():
    dis = distance()
    print (dis, 'mm')
    sleep_ms(300)

# Main Routine
setup()
while(1):
    loop()