PZ-26 · Sound Effects — sounds.boom.play()

Sound Effects — sounds.boom.play()

A click that makes no sound feels empty. A pop, a chime, a thud — even a tiny audio clip makes a game feel alive. Today you'll wire one-shot sound effects to game events using Pygame Zero's beautifully simple sounds object.

⏱ 1 hour🎮 Concept lesson📚 After PZ-25💻 VS Code or Thonny (desktop Python)

Learning Goals

3 min

By the end of this lesson you can:

Place a .wav or .ogg file in the sounds/ folder and play it with sounds.name.play().
Trigger a different sound effect for at least two distinct game events (click, score, collision).
Find free, usable sound clips on freesound.org and name them correctly for Pygame Zero.

Warm-Up · Sprite Direction Recap

5 min

Last lesson you animated a sprite by choosing frames based on movement direction. Predict what this snippet prints before you run it:

speed_x = -5
if speed_x < 0:
    facing = "left"
else:
    facing = "right"
print("Facing:", facing)

Show the answer

Output

Facing: left

Speed is negative, so the sprite faces left. The same logic will soon decide which sound to play.

New Concept · The sounds Object

12 min

Think of sounds like a jukebox that already loaded every track you put in the sounds/ folder. You just say the song's name and add .play(). No loading code. No file handles. No fuss.

Folder layout

Create a folder called sounds/ next to your Python file. Drop a short audio clip inside it:

my_game/
├── mygame.py
└── sounds/
    ├── pop.wav
    └── chime.ogg

Rules for the filenames:

Lowercase letters and underscores only — big_boom.wav, not Big Boom.wav.
Extension must be .wav or .ogg. MP3 is not supported.

Playing a sound

# play sounds/pop.wav once
sounds.pop.play()

The filename without extension becomes the attribute name. pop.wav → sounds.pop. big_boom.ogg → sounds.big_boom.

Where to fire it

Call .play() inside any event hook — on_mouse_down, on_key_down, or inside update() when a collision is detected. Pygame Zero will not play the same sound twice at the same instant, so double-calls are safe.

Worked Example · Clickable Sound Button

12 min

Faiz builds a simple demo: clicking a green rectangle plays a pop sound; pressing SPACE plays a chime. Two events, two different sounds. Save as sound_demo.py.

# sound_demo.py — two sounds on two events
import pgzrun

WIDTH = 480
HEIGHT = 320
TITLE = "Sound Demo"

# Rectangle the player can click
button_rect = Rect((160, 120), (160, 80))

def draw():
    screen.fill("black")
    screen.draw.filled_rect(button_rect, "seagreen")
    screen.draw.text(
        "Click me!",
        center=button_rect.center,
        fontsize=28,
        color="white",
    )
    screen.draw.text(
        "SPACE = chime",
        topleft=(10, 10),
        fontsize=20,
        color="grey",
    )

def on_mouse_down(pos, button):
    if button_rect.collidepoint(pos):
        sounds.pop.play()        # sounds/pop.wav

def on_key_down(key):
    if key == keys.SPACE:
        sounds.chime.play()      # sounds/chime.ogg

pgzrun.go()

Notice that on_mouse_down receives the click position. We check with collidepoint before playing — only a click inside the button triggers the sound.

A black window with a green button. Clicking inside it plays pop.wav; pressing SPACE plays chime.ogg.

Try It Yourself

13 min

01 🟢 Third sound on right-click

Add a third sound — sounds.whoosh.play() — that fires when the player right-clicks anywhere on the screen. In Pygame Zero a right-click gives button == mouse.RIGHT.

Hint

def on_mouse_down(pos, button):
    if button == mouse.RIGHT:
        sounds.whoosh.play()
    elif button_rect.collidepoint(pos):
        sounds.pop.play()

02 🟡 Sound on a timer

Use clock.schedule_interval to play sounds.tick.play() every 2 seconds — like a metronome. Stop it after 8 seconds with clock.unschedule.

Hint

import pgzrun

WIDTH = 400
HEIGHT = 300
tick_count = 0

def play_tick():
    global tick_count
    sounds.tick.play()
    tick_count += 1
    if tick_count >= 4:
        clock.unschedule(play_tick)

clock.schedule_interval(play_tick, 2)
pgzrun.go()

Mini-Challenge · Debug Nurul's Noisy Button

8 min

Nurul wanted her button to play a sound only when clicked inside. Instead, the sound plays wherever she clicks. Find the two bugs:

# nurul_sound.py — buggy
import pgzrun

WIDTH = 400
HEIGHT = 300
btn = Rect((100, 100), (200, 80))

def draw():
    screen.fill("navy")
    screen.draw.filled_rect(btn, "orange")

def on_mouse_down(pos, button):
    sounds.pop.play()            # Bug 1
    if btn.collidepoint(pos):
        pass

pgzrun.go()

Show the fixes

# nurul_sound.py — fixed
import pgzrun

WIDTH = 400
HEIGHT = 300
btn = Rect((100, 100), (200, 80))

def draw():
    screen.fill("navy")
    screen.draw.filled_rect(btn, "orange")

def on_mouse_down(pos, button):
    if btn.collidepoint(pos):    # Fix 1: guard the sound with the collision check
        sounds.pop.play()        # Fix 2: play inside the if block, not before it

pgzrun.go()

Bug 1: sounds.pop.play() was before the if, so it always ran. Bug 2: the pass meant nothing happened inside the correct branch. Swap them.

It works if…

the pop sound plays only when you click inside the orange rectangle

Recap

3 min

Drop a .wav or .ogg file into the sounds/ folder next to your Python file. Pygame Zero loads it automatically — you just callsounds.filename.play() inside any event hook or in update()when a game condition is met. Lowercase filenames, no spaces.

Vocabulary Card

sounds: A Pygame Zero object that auto-loads every file in the sounds/ folder. Attribute name = filename without extension.
.play(): Plays a sound once from the beginning. Safe to call multiple times — Pygame Zero queues simultaneous calls.
freesound.org: A Creative Commons library of free audio clips you can download and use in your games.
.wav / .ogg: The two audio formats Pygame Zero accepts for sound effects. MP3 is not supported.

Homework

4 min

Find two short sound clips on freesound.org(search "pop" and "beep"). Download them as .wav, rename them pop.wav and beep.wav, and place them in sounds/. Write a Pygame Zero program that draws two coloured rectangles and plays a different sound when you click each one. Save as two_sounds.py and bring a screenshot to the next class.

Sample · `two_sounds.py`

# two_sounds.py — two buttons, two sounds
import pgzrun

WIDTH = 480
HEIGHT = 300
TITLE = "Two Sounds"

rect_a = Rect((60, 110), (140, 80))
rect_b = Rect((280, 110), (140, 80))

def draw():
    screen.fill("black")
    screen.draw.filled_rect(rect_a, "tomato")
    screen.draw.text("POP", center=rect_a.center, fontsize=30, color="white")
    screen.draw.filled_rect(rect_b, "dodgerblue")
    screen.draw.text("BEEP", center=rect_b.center, fontsize=30, color="white")

def on_mouse_down(pos, button):
    if rect_a.collidepoint(pos):
        sounds.pop.play()
    elif rect_b.collidepoint(pos):
        sounds.beep.play()

pgzrun.go()

Colours and label text are yours to choose. The key skill: two separate collidepoint guards, each playing its own sound.

Sound Effects — sounds.boom.play()

⏱ 1 hour🎮 Concept lesson📚 After PZ-25💻 VS Code or Thonny (desktop Python)

# sound_demo.py — two sounds on two events import pgzrun WIDTH = 480 HEIGHT = 320 TITLE = "Sound Demo" # Rectangle the player can click button_rect = Rect((160, 120), (160, 80)) def draw(): screen.fill("black") screen.draw.filled_rect(button_rect, "seagreen") screen.draw.text( "Click me!", center=button_rect.center, fontsize=28, color="white", ) screen.draw.text( "SPACE = chime", topleft=(10, 10), fontsize=20, color="grey", ) def on_mouse_down(pos, button): if button_rect.collidepoint(pos): sounds.pop.play() # sounds/pop.wav def on_key_down(key): if key == keys.SPACE: sounds.chime.play() # sounds/chime.ogg pgzrun.go()

import pgzrun WIDTH = 400 HEIGHT = 300 tick_count = 0 def play_tick(): global tick_count sounds.tick.play() tick_count += 1 if tick_count >= 4: clock.unschedule(play_tick) clock.schedule_interval(play_tick, 2) pgzrun.go()

# nurul_sound.py — buggy import pgzrun WIDTH = 400 HEIGHT = 300 btn = Rect((100, 100), (200, 80)) def draw(): screen.fill("navy") screen.draw.filled_rect(btn, "orange") def on_mouse_down(pos, button): sounds.pop.play() # Bug 1 if btn.collidepoint(pos): pass pgzrun.go()

# nurul_sound.py — fixed import pgzrun WIDTH = 400 HEIGHT = 300 btn = Rect((100, 100), (200, 80)) def draw(): screen.fill("navy") screen.draw.filled_rect(btn, "orange") def on_mouse_down(pos, button): if btn.collidepoint(pos): # Fix 1: guard the sound with the collision check sounds.pop.play() # Fix 2: play inside the if block, not before it pgzrun.go()

Learning Goals

Warm-Up · Sprite Direction Recap

New Concept · The sounds Object

Folder layout

Playing a sound

Where to fire it

Worked Example · Clickable Sound Button

Try It Yourself

Mini-Challenge · Debug Nurul's Noisy Button

Recap

Vocabulary Card

Homework

Sample · two_sounds.py

Learning Goals

Warm-Up · Sprite Direction Recap

New Concept · The sounds Object

Folder layout

Playing a sound

Where to fire it

Worked Example · Clickable Sound Button

Try It Yourself

Mini-Challenge · Debug Nurul's Noisy Button

Recap

Vocabulary Card

Homework

Sample · two_sounds.py

Sample · `two_sounds.py`

Sample · `two_sounds.py`