INMP441 I²S MEMS Microphone Module (Omnidirectional 24-bit 1.8–3.3 V) – For ESP32/ESP8266

Compact digital MEMS microphone breakout using the INMP441 sensor (often listed as “NMP441”). Outputs 24-bit I²S audio at 1.8–3.3 V, pairs cleanly with ESP32/ESP8266 for voice detection, sound level logging, and audio experiments.

Features:

• Digital I²S interface (no external ADC) – up to 24-bit data.
• Omnidirectional bottom-port MEMS capsule.
• Sensitivity: −26 dBFS (typ). SNR: ~61 dBA.
• Supply: 1.8–3.3 V (3.3 V typical on ESP32 projects).
• Selectable L/R pad for stereo arrays and beamforming.

The I²S (Inter-IC Sound) interface on the INMP441 MEMS microphone is a synchronous serial interface standard used specifically for connecting digital audio devices together.

Because the INMP441 has a built-in Analog-to-Digital Converter (ADC), it outputs clean, fully digitized 24-bit audio directly. This completely bypasses the need for an external ADC or an analog pre-amplifier, preventing the electrical noise common in analog microphone circuits.

The 3 Essential I²S Pins

To transmit audio data to a microcontroller (like an ESP32), the I²S interface relies on three core signal lines:

• BCLK / SCK (Bit Clock / Serial Clock): This is the heartbeat of the data transfer. The clock pulses once for each single bit of audio data sent.

• LRCLK / WS (Left/Right Clock / Word Select): This signal tells the microcontroller whether the data being sent belongs to the Left audio channel or the Right audio channel. It toggles at the actual audio sampling frequency (e.g., 44.1 kHz).

• SD / DOUT (Serial Data / Data Out): This is the actual data line where the digitized 24-bit audio binary bits are streamed out, one bit at a time, perfectly synchronized with the Bit Clock.

Technical Specifications:

Specifications (module).
Sensor IC: INMP441 (TDK InvenSense).
Interface: I²S (BCLK/SCK, LRCLK/WS, DOUT/SD).
Supply voltage (VDD): 1.62–3.63 V (spec), typical use 3.3 V.
Current: ~1.4 mA @1.8 V (typ.).
Sensitivity: −26 dBFS (typ).
SNR: 61 dBA (typ).
Frequency response (seller stated): ~60 Hz–15 kHz.
Port: Bottom (keep port unobstructed).
Package Type: PCB (requires assembly/solder).

INMP441 Wiring Guide: To get up and running quickly with your ESP32, use the following standard I²S hardware pin connections:

• VCC > Connect to 3.3V (Power Supply)
• GND > Connect to GND (Ground)
• SCK > Connect to GPIO 14 (Serial Data Clock)
• WS > Connect to GPIO 15 (Word Select / Clock)
• SD > Connect to GPIO 32 (Serial Data Output)
• L/R > Connect to GND (For Left Channel Mono)

💻 Software & ESP32 Quick Start Works perfectly with the standard Arduino 'I2S.h' or 'ESP32-Microphone' libraries. Use this micro-snippet in the Arduino IDE to test your connection:

C++

#include <driver/i2s.h>
#define I2S_WS 15
#define I2S_SD 32
#define I2S_SCK 14
void setup() {
Serial.begin(115200);
// Standard I2S config goes here
Serial.println("INMP441 Active!");
}
void loop() {}

Package includes: 1x INMP441 I²S MEMS Microphone Module (omnidirectional).

*The image is for illustrative purposes only. Due to variations in camera settings, lighting, manufacturing processes, monitors, and supply, colours may differ. Product appearance and specifications are subject to change without notice.

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