Sound Parts and Components
This page lists the electronic parts you will need for the sound labs in this section. Most parts cost under $5 and are available on eBay, AliExpress, Amazon, or Adafruit.
Speakers
A speaker turns an electrical signal into sound waves. For MicroPython projects you need a small passive speaker — one with no built-in amplifier.
| Part | Specifications | Use |
|---|---|---|
| Small round speaker | 4 Ω, 0.5 W, 40 mm | General purpose, works with PAM8302A |
| Small round speaker | 8 Ω, 1 W, 50 mm | Louder, works with MAX98357A |
| Mini speaker (28 mm) | 8 Ω, 0.25 W | Very small projects, low volume |
Watch Out!
Never connect a speaker directly to a GPIO pin. The pin can only supply
about 3 mA of current — not nearly enough to move a speaker cone. You will
burn out the GPIO pin or get no sound at all. Always use an amplifier module
between the Pico and the speaker.
Amplifier Modules
An amplifier takes the small signal from the Pico and boosts it enough to drive a speaker.
PAM8302A — Mono Class D Amplifier
The PAM8302A is a miniature mono amplifier that delivers up to 2.5 W into a 4 Ω speaker. It is perfect for simple projects that just need one speaker.
- Input: standard 3.3 V audio signal from the Pico
- Output: up to 2.5 W into 4 Ω
- Power supply: 2.5 V to 5.5 V
- Cost: about $0.50–$1 each
Search eBay or AliExpress for PAM8302A.
MAX98357A — I2S Mono DAC + Amplifier
The MAX98357A is the best choice for playing WAV files and digital audio. It combines a Digital-to-Analog Converter (DAC) and a 3 W amplifier in one small board, and connects over the I2S bus.
- Input: I2S digital audio from the Pico
- Output: up to 3 W into 4 Ω
- Power supply: 3.3 V or 5 V
- Cost: about $1–$2 each
Buzzers
A buzzer is the simplest way to make sound with the Pico.
| Type | How it works | Notes |
|---|---|---|
| Active buzzer | Beeps at a fixed pitch when you apply power | Easiest — just turn it on and off |
| Passive buzzer | Requires a PWM signal at the frequency you want | More flexible — play any tone |
Most labs in this section use a passive buzzer so you can control the pitch. A passive buzzer costs about $0.10–$0.50.
Key Idea
An active buzzer sounds like a smoke alarm — one fixed pitch, on or off.
A passive buzzer is like a tiny speaker — you choose the pitch by changing
the frequency of the signal you send to it.
Microphones
To record sound or detect noise levels, you need a microphone module.
| Module | Interface | Use |
|---|---|---|
| INMP441 | I2S digital | High-quality voice recording |
| MAX9814 | Analog | Simple noise level detection |
| KY-037 | Digital + analog | Basic clap/sound trigger |
The INMP441 is recommended for voice and audio recording because it connects over I2S and produces clean 24-bit digital audio.
Complete Parts List for the Sound Labs
| Part | Labs that use it | Approximate cost |
|---|---|---|
| Passive buzzer | Play a Tone, Play a Scale, Play Mario | $0.10–$0.50 |
| PAM8302A amplifier | Eight Key Piano, Tone Generator | $0.50–$1 |
| 4 Ω speaker (40 mm) | With PAM8302A | $0.50–$1 |
| MAX98357A I2S amp | Playing Audio File, DAC lab | $1–$2 |
| 8 Ω speaker (50 mm) | With MAX98357A | $0.50–$1 |
| INMP441 I2S microphone | Microphone INMP441 lab | $1–$3 |