【Follow me第二季第4期】任务三 学调试PDM麦克风，通过串口打印收音数据和音频波形

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【Follow me第二季第4期】任务三 学调试PDM麦克风，通过串口打印收音数据和音频波形 [复制链接]

 

硬件部分

ST MP34DT06JTR MEMS麦克风
  ▪ AOP = 122.5 dBSPL
  ▪ 64 dB信噪比
  ▪ 全向灵敏度
  ▪ -26 dBFS ± 1 dB灵敏度

 

硬件连接

 

代码部分

先安装PDM库

#include <WiFiNINA.h>
#include <PDM.h>

bool LED_SWITCH = false;

// default number of output channels
static const char channels = 1;

// default PCM output frequency
static const int frequency = 20000;

// Buffer to read samples into, each sample is 16-bits
short sampleBuffer[512];

// Number of audio samples read
volatile int samplesRead;

void setup() {
  Serial.begin(115200);
  pinMode(LEDB, OUTPUT);
  while (!Serial);
  // Configure the data receive callback
  PDM.onReceive(onPDMdata);

  // Optionally set the gain
  // Defaults to 20 on the BLE Sense and -10 on the Portenta Vision Shields
  // PDM.setGain(30);

  // Initialize PDM with:
  // - one channel (mono mode)
  // - a 16 kHz sample rate for the Arduino Nano 33 BLE Sense
  // - a 32 kHz or 64 kHz sample rate for the Arduino Portenta Vision Shields
  if (!PDM.begin(channels, frequency)) {
    Serial.println("Failed to start PDM!");
    while (1);
  }
}

void loop() {
  // Wait for samples to be read
  if (samplesRead) {

    // Print samples to the serial monitor or plotter
    for (int i = 0; i < samplesRead; i++) {
      if (channels == 2) {
        Serial.print("L:");
        Serial.print(sampleBuffer[i]);
        Serial.print(" R:");
        i++;
      }
      Serial.println(sampleBuffer[i]);

      if (sampleBuffer[i] > 10000 || sampleBuffer[i] <= -10000) {
        LED_SWITCH = !LED_SWITCH;
        if (LED_SWITCH) {
          Serial.println();
          digitalWrite(LEDR, HIGH);
          Serial.println("ON!");
          Serial.println();
          delay(1000);
        }
        else {
          Serial.println();
          digitalWrite(LEDR, LOW);
          Serial.println("OFF!");
          Serial.println();
          delay(1000);
        }
      }
    }

    // Clear the read count
    samplesRead = 0;
  }
}

/**
   Callback function to process the data from the PDM microphone.
   NOTE: This callback is executed as part of an ISR.
   Therefore using `Serial` to print messages inside this function isn't supported.
 * */
void onPDMdata() {
  // Query the number of available bytes
  int bytesAvailable = PDM.available();

  // Read into the sample buffer
  PDM.read(sampleBuffer, bytesAvailable);

  // 16-bit, 2 bytes per sample
  samplesRead = bytesAvailable / 2;
}

 

现象是打一个响指就会让红灯亮，再打一个就会关闭红灯

 

 

输出的数据如下