#1.	Write a micropython code – Blind stick using Ultrasonic Sensor(use Components – Raspberry Pi PICO, Ultrasonic sensor, Buzzer)


from machine import Pin, PWM
import utime

trig_pin = Pin(4, Pin.OUT)
echo_pin = Pin(5, Pin.IN)
buzzer_pin = Pin(15, Pin.OUT)
pwm = PWM(buzzer_pin)

def measure_distance():
    trig_pin.high()
    utime.sleep_us(10)
    trig_pin.low()

    while echo_pin.value() == 0:
        pulse_start = utime.ticks_us()
    while echo_pin.value() == 1:
        pulse_end = utime.ticks_us()
    pulse_duration = pulse_end - pulse_start

    distance = (pulse_duration * 34300) / 2 / 1000000
    return distance

def activate_buzzer():
    pwm.freq(1000)
    pwm.duty_u16(32768)  

def deactivate_buzzer():
    pwm.duty_u16(0) 

while True:
    distance = measure_distance()
    print("Distance:", distance, "cm")
    if distance < 30:  
        activate_buzzer()
    else:
        deactivate_buzzer()
    utime.sleep(0.1)