CODING

MUSIC BOX
Tutorial
ch4listing1.py
import pygame.mixer
from pygame.mixer import Sound
Language
>PYTHON 3
DOWNLOAD:
magpi.cc/2bhwqlH
pygame.mixer.init()
drum = Sound("samples/DrumBuzz.wav")
while True:
drum.play()
ch4listing2.py
Below Each time you press a button, the assigned sound sample
will play through a connected speaker
>STEP-04
Add a second button
We’ll now add a second button, as in the diagram.
Wire it to GPIO 3 and the ground rail. Open a new file
in Python 3 IDLE, enter the code from ch4listing3.py,
and save it in musicbox. Note that rather than
assigning the Button objects and sounds to the pins
individually, we’re using a dictionary structure to
assign their numbers to sound samples:
sound_pins = {
2: Sound("samples/DrumBizz.wav"),
3: Sound("samples/CymbalCrash.wav"),
}
We then create a list of buttons on all the pin
numbers in the sound_pins dictionary: buttons =
[Button(pin) for pin in sound_pins]
Finally, we create a for loop that looks up
each button in the dictionary and plays the
appropriate sound:
for button in buttons:
sound = sound_pins[button.pin.number]
button.when_pressed = sound.play
Run the program and press each button to hear a
different sound.
>STEP-05
Add more buttons
The way we have structured the program makes it
easy to add extra buttons and assign them to sound
samples. Just connect each button to a GPIO number
pin (not any other type) and the ground rail, as before.
Then add the GPIO pin numbers and sounds to the
dictionary, as in the following example:
from gpiozero import Button
import pygame.mixer
from pygame.mixer import Sound
from signal import pause
pygame.mixer.init()
button = Button(2)
drum = Sound("samples/DrumBuzz.wav")
button.when_pressed = drum.play
pause()
ch4listing3.py
from gpiozero import Button
import pygame.mixer
from pygame.mixer import Sound
from signal import pause
pygame.mixer.init()
sound_pins = {
2: Sound("samples/DrumBuzz.wav"),
3: Sound("samples/CymbalCrash.wav"),
}
buttons = [Button(pin) for pin in sound_pins]
for button in buttons:
sound = sound_pins[button.pin.number]
button.when_pressed = sound.play
pause()
sound_pins = {
2: Sound("samples/DrumBizz.wav"),
3: Sound("samples/CymbalCrash.wav"),
4: Sound("samples/Gong.wav"),
14: Sound("samples/HandClap.wav"),
}
raspberrypi.org/magpi January 2017
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