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Playing Tones on a Passive Buzzer with a Raspberry Pi 4B (PWM)

Wire a passive buzzer to a Raspberry Pi 4B GPIO pin and play a real, changing musical pitch with GPIO.PWM() — unlike an Active Buzzer, this one only sounds while your script is actively driving it.

Try this directly in the free Raspberry Pi 4B simulator — no hardware or signup required. New to the GPIO header? Start with the interactive pinout guide.

What you’ll need

  • Raspberry Pi 4B
  • Passive Buzzer

Step by step

  1. Drag Raspberry Pi 4B onto the Canvas.
  2. Drag the Passive Buzzer onto the Canvas — connects via drawn wires, not breadboard legs.
  3. Hover over its 2 pins to confirm the labels: Positive (+) and Negative (−).
  4. Wire it up: Positive → a GPIO pin (e.g. pin 37). Negative → a Pi GND pin.
  5. Go to the Code tab and write a script that plays a short rising scale:
import RPi.GPIO as GPIO
import asyncio
 
buzzerPin = 37
 
GPIO.setmode(GPIO.BOARD)
GPIO.setup(buzzerPin, GPIO.OUT)
 
pwm = GPIO.PWM(buzzerPin, 262)   # start at middle C (262Hz)
pwm.start(50)                    # 50% duty cycle — a passive buzzer needs this to make any sound at all
 
notes = [262, 294, 330, 349, 392]   # C, D, E, F, G
 
for note in notes:
    print(f"Playing {note}Hz")
    pwm.ChangeFrequency(note)
    await asyncio.sleep(0.4)
 
pwm.stop()
GPIO.cleanup()
  1. Click Start.

What “working correctly” looks like

  • You should hear 5 distinct, rising tones, one every 0.4 seconds, matching the printed frequency in the Console each time.
  • The buzzer's own note indicator stays animated continuously through the whole sequence — unlike the Active Buzzer, which only ever plays one fixed pitch, this one's pitch genuinely changes with ChangeFrequency().

If something’s wrong

  • Nothing happens, not even the note indicator → a Passive Buzzer needs BOTH pwm.start(...) AND at least one ChangeFrequency() call — a bare GPIO.output(buzzerPin, GPIO.HIGH) (the Active Buzzer's own approach) produces no sound here at all, since this component has no built-in oscillator of its own.
  • You hear a tone but it never changes pitch → confirm you're calling pwm.ChangeFrequency(...) inside the loop, not just once before it starts.