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2.4. Buzzer Beep

Under construction
Short example demonstration video

In this example we will use a passive buzzer to play a melody. The buzzer functions like a small speaker, it requires AC audio signal to produce sound. To make it play different melodies and tones we simply change the frequency of the signal sent to it.

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At the end of this example you will learn:

  • How to play sound/melody from a passive buzzer
  • How to use PWM for different frequencies
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Parts required:

  • Soldered NULA Mini Board
  • Breadboard
  • 1 x Buzzer
  • Some jumper wires
Under construction
Required components

Putting the components together​

  • Place the buzzer in the breadboard, connect the positive pin to GPIO 5, and negative to GND.
  • Positive pin should be labeled on top of the buzzer.
Under construction
Components connected together

Code Example​

Import necessary modules, PWM is used to control the tone output from the buzzer.

from machine import Pin, PWM
import time

Create a PWM object on pin 5.

buzzer = PWM(Pin(5))

Here we define some common notes along with their frequencies in Hz.

C4 = 262
D4 = 294
E4 = 330
F4 = 349
G4 = 392
A4 = 440

Out of those notes we defined, we can create a melody by putting them in a list. We also set duration to play each note.

melody = [C4, D4, E4, F4, G4, A4, G4, F4, E4, D4, C4]
duration = 200

Loop through the melody and play each note with a small pause in between. In the end disable the PWM output for the buzzer.

for note in melody:
    buzzer.freq(note)           # Set buzzer frequency based on the note
    buzzer.duty(512)            # 50% duty (sound on)
    time.sleep_ms(duration)     # Play note for defined duration
    buzzer.duty(0)              # 0% duty (sound off)
    time.sleep_ms(150)          # Short pause between notes

buzzer.deinit()

Full Example​

2.4_Buzzer_Beep.py