【Follow me第二季第4期】在Arduino下使用SD卡录制声音
本帖最后由 eew_9XVJps 于 2024-12-3 09:02 编辑<p align="left"><b>自定任务：</b>Arduino Nano RP2040 Connect板载的PDM麦克风实现录音功能</p>
<p> 看到板载有麦克风为什么不试一下录制声音呢，因此想通过板载的PDM麦克风实现声音拾取，并将收集到的数据以WAV格式形式存储在SD卡中。SD卡通过SPI接口实现与主控板通讯，SPI引脚直接使用了默认引脚。</p>
<p> </p>
<p> 我使用的SD卡外置模块为5V供电，需要将主控板的VBUS焊盘连接上来进行供电，否则3V3无法启动。</p>
<p> 流程顺序大体如下：</p>
<p> </p>
<p>目前程序还是有点问题不知道是出在哪里，录音的长度和设定长度一致，但是播放录制的程序明显速度变快了，哪位大佬有空帮我看看问题出在哪里了，程序如下：</p>
<pre>
<code>#include <PDM.h>
#include "wave.h"
#include <SPI.h>
#include "SdFat.h"
const int chipSelect = 10;
// 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;
const int record_time = 30;// second
const char filename[] = "/record.wav";
const int waveDataSize = record_time * 40000;
char partWavData;
// Number of audio samples read
volatile int samplesRead;
FsFile file;// 录音文件
SdFs sd;
void setup() {
Serial.begin(9600);
delay(2000);
if(!sd.begin(SdSpiConfig(chipSelect, DEDICATED_SPI, SD_SCK_MHZ(16))))//初始化SD
{
Serial.println(F("sd init error"));
return;
}
sd.remove(filename);
file = sd.open(filename, O_WRITE|O_CREAT);
if(!file)
{
Serial.println("crate file error");
return;
}
// Configure the data receive callback
auto header = CreateWaveHeader(1, 20000, 16);
header.riffSize = waveDataSize + 44 - 8;
header.dataSize = waveDataSize;
file.write(&header,44);
PDM.onReceive(onPDMdata);
// Optionally set the gain
// Defaults to 20 on the BLE Sense and 24 on the Portenta Vision Shield
PDM.setGain(10);
// 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 Shield
if (!PDM.begin(channels, frequency)) {
Serial.println("Failed to start PDM!");
while (1);
}
else{
Serial.println("start");
}
}
int count = waveDataSize/128;
void loop() {
// Wait for samples to be read
if(count==0){
samplesRead=0;
file.close();
Serial.println("finish");
}
if (samplesRead) {
file.write((const byte*)sampleBuffer, 128);
count--;
// Clear the read count
samplesRead = 0;
}
// if (samplesRead) {
// Serial.println(samplesRead);
// 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);//每次64样本
// 16-bit, 2 bytes per sample
samplesRead = bytesAvailable / 2;
}
</code></pre>
<p align="left">对应的WAVE文件内容</p>
<pre>
<code>#include "wave.h"
WAV_HEADER CreateWaveHeader(int numChannels, //声道数
unsigned int sampleRate, //采样率
unsigned short bitsPerSample) //采样位宽
{
WAV_HEADER header;
header.riffSize = 0;
header.numChannels = numChannels;
header.sampleRate = sampleRate;
header.bitsPerSample = bitsPerSample;
header.bytesPerSecond = sampleRate * numChannels * bitsPerSample /8 ;
header.blockAlign = numChannels * bitsPerSample/8;
header.dataSize = 0;
return header;
}</code></pre>
<p align="left">效果图如下，动态效果见视频：</p>
<p> d37d54d962efd3f80ff9f3471e1cf882</p>
<p>有更新了吗？换成14k就好了？</p>
<div style="position: fixed; opacity: 1; height: 300px; width: 100%; font-size: 25px; text-align: center; bottom: 200px; left: 0px; display: none; flex-direction: column; justify-content: center; z-index: 1661789940; top: calc(50% + 0px);"> </div>
yilonglucky 发表于 2024-12-3 17:28
有更新了吗？换成14k就好了？
<p>是的换成14000速率就好了，下面是新录制的视频5e77f76763898e5239c236209725ea1f。</p>
<p>就是没搞明白明明麦克风和WAVE文件里面设置的声道数和速度都一致为啥只有14000采样率才正常。</p>
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