Adafruit
Adafruit PDM MEMS Microphone Breakout
The Adafruit PDM MEMS Microphone Breakout provides a digital audio input using Pulse Density Modulation (PDM) — a common interface in commercial products tha...
The Adafruit PDM MEMS Microphone Breakout provides a digital audio input using Pulse Density Modulation (PDM) — a common interface in commercial products that's distinct from both analogue and I2S microphones. It's ideal for microcontrollers without analogue inputs, and most modern 32-bit processors include a hardware PDM peripheral.
PDM works by clocking the microphone at 1–3 MHz and reading a 1-bit digital output whose pulse density represents the analogue audio signal. When filtered and decimated, this produces clean audio samples. Many platforms (nRF52, RP2040, SAMD51) handle this in hardware with library support, while others may require manual filtering.
Key Features
- PDM Digital Output – 1-bit pulse density modulation, not analogue or I2S
- MEMS Microphone – Compact, high-quality digital microphone element
- 1–3 MHz Clock Rate – Standard PDM clocking compatible with most 32-bit MCUs
- No Analogue Input Required – Fully digital interface, no ADC needed
- Breadboard Friendly – Includes header strip for easy prototyping
Integration Approaches
- Hardware PDM Peripheral – Best option: the MCU handles clocking, filtering, and decimation automatically (nRF52, RP2040, SAMD51, etc.)
- Hardware Peripheral + Manual Filtering – The MCU provides raw PDM data; you apply decimation and filtering in software
- Analogue Filter Hack – Generate the clock externally, apply an analogue low-pass filter on the data line, and read the result as an analogue value
Ideal For
- Voice and audio capture on digital-only microcontrollers
- Sound-reactive projects and audio level detection
- Adding microphone input to boards without analogue pins
Package Contents
- 1× PDM MEMS Microphone Breakout (assembled and tested)
- 1× Header strip for breadboard use
Resources
- PDM Microphone Learn Guide (wiring, schematics, example code, datasheet)
Jargon buster
Plain-language definitions for the technical terms used above.
- ADC
- An analogue-to-digital converter reads a changing voltage and turns it into a number the microcontroller can use. It matters when connecting analogue sensors such as light, sound, or variable-resistor sensors.
- AVR
- AVR is a family of 8-bit microcontrollers used in many classic Arduino-style boards. If a USB host library mentions AVR support, it suggests the examples or compatibility may be aimed at those older microcontroller boards.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- I2S
- I2S is a digital audio interface used to send sound data between chips, such as from a microcontroller to an audio amplifier or DAC. It matters if your project needs cleaner digital audio output than a basic buzzer or PWM signal can provide.
- MEMS microphone
- A tiny microphone made using micro-electromechanical systems, the same style of miniature manufacturing used in many phone sensors. It lets the board detect sound without needing an external microphone, which is useful for noise-reactive projects and simple audio input.
- RP2040
- A microcontroller chip used on many maker boards, with enough speed and flexible I/O for some camera and display projects. Compatibility with RP2040 matters because camera modules often need many pins and careful timing to read image data successfully.
- SAMD51
- A family of 32-bit microcontroller chips used to run the main program on a board. In this kit it handles the display-driving work, so it matters for performance when showing animations and graphics on an LED matrix.
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Brands
Sensors & Input
Related Tutorials
Free guides on learn.littlebird.com.au
