PlayBuzzer

# Circuit from GPIO7

# based on https://raspberrypi.stackexchange.com/questions/30170/piezo-with-python
# 30 Dec 2018

import RPi.GPIO as GPIO
import time

buzzer_num = 7 # Set to the appropriate GPIO pin. Run 'pinout' on RPi terminal for help.

GPIO.setmode(GPIO.BOARD)
GPIO.setup(buzzer_num, GPIO.OUT)

# As taken from pages.mtu.edu/~suits/notefreqs.html :
# Encouraged to add more (flats/sharps, more octaves, or general function)

c = 261.63
d = 293.66
e = 329.63
f = 349.23
g = 392
a = 440
b = 493.88
C_hi = 523.25

# r = 'Rest', no sound
r = 1

# Initialize the buzzer: 
# We use pulse-width modulation like you would see in LED brightness configuration
p = GPIO.PWM(buzzer_num, 100)


# based on the frequencies above, we define callable functions which will return a changeFrequency event.
def C():
    return p.ChangeFrequency(c)
def D():
    return p.ChangeFrequency(d) 
def E():
    return p.ChangeFrequency(e)
def F():
    return p.ChangeFrequency(f)
def G():
    return p.ChangeFrequency(g)
def A():
    return p.ChangeFrequency(a)
def B():
    return p.ChangeFrequency(b)
def C2():
    return p.ChangeFrequency(C_hi)
def R():
    return p.ChangeFrequency(r)

# Given a frequency, we would like to define a note to translate from string 'A' played for a certain amount of time.

def note(value, timer):

    # Not the most pythonic way... improvements welcome:
  
    if value == 'C':
        time.sleep(timer)
        C()
        time.sleep(timer)

    elif value == 'D':
        time.sleep(timer)
        D()
        time.sleep(timer)

    elif value == 'E':
        time.sleep(timer)
        E()
        time.sleep(timer)

    elif value == 'F':
        time.sleep(timer)
        F()
        time.sleep(timer)

    elif value == 'G':
        time.sleep(timer)
        G()
        time.sleep(timer)

    elif value == 'A':
        time.sleep(timer)
        A()
        time.sleep(timer)

    elif value == 'B':
        time.sleep(timer)
        B()
        time.sleep(timer)

    elif value == 'C2':
        time.sleep(timer)
        C2()
        time.sleep(timer)

    elif value == 'R':
        time.sleep(timer)
        R()
        time.sleep(timer)
        
# Example, with constant note length (as seen in Play function):
Cscale = ['C', 'D', 'E', 'F', 'G', 'A', 'B', 'C2']

tune = ['C', 'R', 'C', 'R', 'C', 'G', 'E', 'C']

def Play(numTimes, speed):  # Play our tune/scale numTimes with given speed
    for i in range(0,numTimes):
        print("Iteration: " + str(i+1))
        time.sleep(speed) # Wait
        p.start(100)            # start the PWM on 100  percent duty cycle
        p.ChangeDutyCycle(90)   # change the duty cycle to 90%
        
        # Set up our scale:
        for key in Cscale + Cscale[::-1] + 2*Cscale[0:1]:
            # Play:
            note(key, speed/2)
        # Stop the buzzer: (see object p above)
        p.stop()                # stop the PWM output

    print("Done, cleaning up.") # When loop is complete, clean the GPIO pins.
    GPIO.cleanup()

iterations = 1
speed = 0.6

Play(iterations, speed)