from machine import Pin,PWM
import time
alarm_distance = 150   #cm

# Define GPIO pins for the ultrasonic module

trigger_pin = Pin(14, machine.Pin.OUT)
echo_pin = Pin(15, machine.Pin.IN)

red_led_pin = PWM(Pin(7,Pin.OUT))

# Function to measure distance using the ultrasonic module

def measure_distance():
    trigger_pin.low()
    time.sleep_us(2)
    trigger_pin.high()
    time.sleep_us(10)
    trigger_pin.low()
    while echo_pin.value() == 0:
        signaloff = time.ticks_us()

    while echo_pin.value() == 1:
        signalon = time.ticks_us()

    # Calculate the duration of the Echo signal
    timepassed = signalon - signaloff
    # Calculate the distance based on the speed of sound
    distance = (timepassed * 0.0343) / 2

    return distance

def mapFromTo(x,a,b,c,d):
   y=(x-a)/(b-a)*(d-c)+c
   return y

   
red_led_pin.freq(1000)


# Measure the distance and print the result

while True:
    distance = measure_distance()
    distance = int(mapFromTo(distance,2,404,65536,0))
    print (distance)
    red_led_pin.duty_u16(distance)
    time.sleep(0.5)


    time.sleep(2)