from machine import Pin, time_pulse_us , PWM
from time import sleep_us, sleep

buzzer = PWM(Pin(15))

def tone(freq, t):
    buzzer.duty(512)  # duty cycle = 50%
    buzzer.freq(freq)
    sleep(t)

def silent(t):
    buzzer.duty(0)
    sleep(t)

notes = [262,294,330,349,392,440,494,524]
#notes = [659, 587, 370, 415,554, 494, 294, 330,494, 440, 277, 330,440]

def melody () :
    for n in notes :
        tone(n, 0.25)
        silent(0.1)

# === CONFIGURATION ===
TRIGGER_PIN = 26
ECHO_PIN = 25
MAX_DISTANCE_CM = 400
ECHO_TIMEOUT_US = MAX_DISTANCE_CM * 2 / 0.0343  # time for max range

# === SETUP PINS (initialized once) ===
trigger = Pin(TRIGGER_PIN, Pin.OUT)
echo = Pin(ECHO_PIN, Pin.IN)

def check_distance():
    trigger.value(0)
    sleep_us(2)
    # Send 10µs pulse
    trigger.value(1)
    sleep_us(10)
    trigger.value(0)

    pulse_time = time_pulse_us(echo, 1, int(ECHO_TIMEOUT_US))
    return pulse_time
 
def distance_cm():
    pulse_time = check_distance()
    distance = (pulse_time / 2) * 0.0343
    if distance < 2 : 
       distance = 0 
    return distance

while True:

    d_cm = distance_cm()
    print("Distance: ", d_cm, "cm")
    if d_cm < 30 :
        melody() 
    else :
        silent(0.1)
    sleep(0.5)