How to Use Microphone Module: Examples, Pinouts, and Specs

The SmartElex I2S MEMS Microphone Module is a compact and efficient device designed to convert sound waves into electrical signals. This module utilizes MEMS (Micro-Electro-Mechanical Systems) technology and supports the I2S (Inter-IC Sound) protocol for digital audio data transmission. It is ideal for applications requiring high-quality audio input, such as voice recognition systems, audio recording devices, and communication systems.

• Voice recognition systems (e.g., smart assistants)
• Audio recording and streaming
• IoT devices with sound input capabilities
• Communication systems (e.g., teleconferencing)
• Environmental sound monitoring

The following table outlines the key technical details of the SmartElex I2S MEMS Microphone Module:

The SmartElex I2S MEMS Microphone Module has the following pinout:

1. Power Supply: Connect the VDD pin to a regulated power source (1.8V to 3.6V) and the GND pin to the ground.
2. I2S Interface: Connect the WS, SCK, and SD pins to the corresponding I2S pins on your microcontroller or audio processor.
   • WS: Used to select the left or right audio channel.
   • SCK: Provides the clock signal for data synchronization.
   • SD: Outputs the digital audio data.
3. Configuration: Ensure your microcontroller or processor is configured to read I2S data at the appropriate clock rate and channel settings.

• Power Supply: Use a stable and noise-free power source to avoid interference in audio signals.
• Clock Signal: Ensure the SCK signal is accurate and matches the required frequency for proper data synchronization.
• Placement: Place the microphone module away from high-frequency noise sources to maintain audio quality.
• Decoupling Capacitor: Add a decoupling capacitor (e.g., 0.1 µF) near the VDD pin to filter out power supply noise.

The Arduino UNO does not natively support I2S, but you can use an external I2S interface module or a microcontroller like the ESP32, which has built-in I2S support. Below is an example code snippet for using the I2S MEMS Microphone Module with an ESP32:

#include <driver/i2s.h>

// I2S configuration
#define I2S_NUM         I2S_NUM_0  // I2S port number
#define I2S_WS_PIN      25         // Word Select pin
#define I2S_SCK_PIN     26         // Serial Clock pin
#define I2S_SD_PIN      22         // Serial Data pin

void setup() {
  // Configure I2S
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX), // Master mode, receive
    .sample_rate = 16000,                               // Sampling rate
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,       // 16-bit audio
    .channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,        // Left channel only
    .communication_format = I2S_COMM_FORMAT_I2S,       // I2S format
    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,           // Interrupt level
    .dma_buf_count = 8,                                 // Number of DMA buffers
    .dma_buf_len = 64                                   // Buffer length
  };

  // Configure I2S pins
  i2s_pin_config_t pin_config = {
    .bck_io_num = I2S_SCK_PIN,  // Serial Clock
    .ws_io_num = I2S_WS_PIN,    // Word Select
    .data_out_num = I2S_PIN_NO_CHANGE, // Not used
    .data_in_num = I2S_SD_PIN   // Serial Data
  };

  // Install and start I2S driver
  i2s_driver_install(I2S_NUM, &i2s_config, 0, NULL);
  i2s_set_pin(I2S_NUM, &pin_config);
}

void loop() {
  // Buffer to store audio data
  int16_t audio_buffer[128];
  size_t bytes_read;

  // Read audio data from I2S
  i2s_read(I2S_NUM, audio_buffer, sizeof(audio_buffer), &bytes_read, portMAX_DELAY);

  // Process audio data (e.g., send to a server or analyze)
}

1. No Audio Output:

   • Ensure the power supply is within the specified range (1.8V to 3.6V).
   • Verify the I2S clock signal (SCK) is correctly configured.
   • Check the connections for WS, SCK, and SD pins.

2. Distorted Audio:

   • Ensure the microphone is not placed near high-frequency noise sources.
   • Verify the sampling rate and bit depth match the module's specifications.

3. Low Sensitivity:

   • Check if the microphone is oriented correctly to capture sound.
   • Ensure there are no obstructions blocking the microphone's sound input.

Q: Can this module be used with a Raspberry Pi?
A: Yes, the I2S MEMS Microphone Module can be connected to a Raspberry Pi using its I2S interface. Ensure the Raspberry Pi is configured to read I2S data.

Q: What is the maximum sampling rate supported?
A: The module supports sampling rates up to 48 kHz, depending on the configuration of the I2S interface.

Q: Can I use this module for stereo audio?
A: Yes, by using two modules and configuring the WS pin appropriately, you can capture stereo audio.

Q: Is this module suitable for outdoor use?
A: The module operates in a wide temperature range (-40°C to +85°C), but it should be protected from moisture and dust for reliable operation.