from machine import Pin,PWM
import time

def ultra():
    trigger.low()
    time.sleep_us(2)
    trigger.high()
    time.sleep_us(5)
    trigger.low()

    while echo.value() == 0:
        signaloff = time.ticks_us()
    while echo.value() == 1:
        signalon = time.ticks_us()
    
    timepassed = signalon - signaloff
    distance = (timepassed * 0.0343) / 2
    # print("The distance from object is ", distance, "cm")
    return distance

green=Pin(1, Pin.OUT)
green.value(0)
motor = PWM(Pin(27))
motor.freq(50)
close_pos = 500000
open_pos = 1450000
motor.duty_ns(close_pos)

trigger = Pin(20, Pin.OUT)
echo = Pin(19, Pin.IN)

while True:
    distance = ultra()
    if distance < 200:
        motor.duty_ns(open_pos)
        green.on()
        print('Door Open!')
    else:
        motor.duty_ns(close_pos)
        green.off()
        print('Door Closed!')

    time.sleep(2)