Microphone Library for Pico

Capture audio from a microphone on your Raspberry Pi Pico or any RP2040 based board. 🎤

Hardware

• RP2040 board

  • Raspberry Pi Pico

• Microphones

  • I2S

    • INMP441 I2S Omnidirectional Microphone

  • Analog

    • Electret Microphone Amplifier - MAX9814 with Auto Gain Control

  • PDM

    • Adafruit PDM MEMS Microphone Breakout

Default Pinout

I2S Microphone

Raspberry Pi Pico / RP2040	Analog Microphone
3.3V	VCC
GND	GND
GPIO 2	SCK
GPIO 3	WS
GPIO 6	SD
GND	L/R

Analog Microphone

Raspberry Pi Pico / RP2040	Analog Microphone
3.3V	VCC
GND	GND
GPIO 26	OUT

PDM Microphone

Raspberry Pi Pico / RP2040	PDM Microphone
3.3V	VCC
GND	GND
GND	SEL
GPIO 2	DAT
GPIO 3	CLK

GPIO pins are configurable in examples or API.

Examples

Git Examples about microphone

Set up Pico SDK

Set up the Pico C/C++ SDK

1. Set PICO_SDK_PATH

   export PICO_SDK_PATH=/path/to/pico-sdk

2. Create build dir, run cmake and make:

   mkdir build
   cd build
   cmake .. -DPICO_BOARD=pico
   make
   

3. Copy example .uf2 to Pico when in BOOT mode.

License

Apache-2.0 License

Acknowledgements

- Mic Analog or Mic PDM

The OpenPDM2PCM library is used to filter raw PDM data into PCM. The TinyUSB library is used in the usb_microphone example.

---

- Mic I2S

Get data raw using I2S protocol and using algorithm fill buffer to decode audio.

Buffer App = Buffer Ring / 4 = Buffer DMA / 8.

To record data, using [TinyUSB](GitHub - hathach/tinyusb: An open source cross-platform USB stack for embedded system) library is used in the usb_microphone example. Buffer output <= 32 bytes <=> 256 bytes in DMA buffer

Using [Audacity software](Download | Audacity ® get audio output

---