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 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)