from machine import *
from time import *

trig = Pin(8,Pin.OUT)
echo = Pin(7,Pin.IN)
RED_LED = Pin(14,Pin.OUT)
Green_LED = Pin(15,Pin.OUT)
buzzer = PWM(Pin(19))
buzzer.freq(1000)

while True:

    trig.value(0)
    sleep_us(2)
    trig.value(1)
    sleep_us(10)
    trig.value(0)


    duration = time_pulse_us(echo, 1)


    distance = (duration * 0.0343) / 2


    print('duration =', duration, 'distance =',distance, 'cm')
    if distance>60 :
        print('Safe')
        Green_LED.value(1) 
        RED_LED.value(0)
        buzzer.duty_u16(0)
    elif distance>=30 and distance<=60 :
        print('Warning')
        Green_LED.value(0)
        RED_LED.value(1)
        buzzer.duty_u16(0)
    elif distance>=0 and distance<=29 :
        print ('Danger')
        Green_LED.value(0)
        RED_LED.value(1)
        buzzer.duty_u16(20000)
    else :
        print("Wrong Input")    
        
    sleep(0.5)