6.3 Simulate the working of a fishing trawler that uses ultrasound beams to detect fish swarms in the ocean and gauge the depth at which the fish are swimming.

from machine import Pin, time_pulse_us
import time

# Pins
trigger = Pin(27, Pin.OUT)
echo = Pin(26, Pin.IN)

# Speed of sound (cm/us)
SPEED = 0.0343

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

    # Measure echo time
    duration = time_pulse_us(echo, 1)

    # Calculate distance (cm)
    distance = (duration * SPEED) / 2
    return distance

while True:
    dist = get_distance()

    print("Depth:", dist/100, "m")

    time.sleep(1)