【搬运】通过超声波控制LED颜色变化

vany5921

             前面提到日本用户用chirp进行声波通讯，下面的案例无需进行声音验证，无需app，只要通过麦克风采集指定频率的声音就可以控制灯光颜色。这里利用了arduinoFFT这个库，分析声音种的指定频率，由于频率较高，人耳难以察觉，因此可以作为通讯手段夹杂在其他声音当中，作为信号发送。代码通过15KHz频率控制红色，16KHz频率控制绿色，17KHz控制蓝色。同样的M5StickC的屏幕也显示相应颜色，由于LED色彩为RGB888,而屏幕色彩为RGB565，因此需要进行转换。用到了三个库，i2s与neopixel可以参考相关例程.原文地址https://homemadegarbage.com/m5stickc02
[mw_shl_code=arduino,true]#include <M5StickC.h>
#include <driver/i2s.h>
#include "arduinoFFT.h"
#include <Adafruit_NeoPixel.h>

Adafruit_NeoPixel pixels(6, 26, NEO_GRB + NEO_KHZ800);  //定义26引脚

#define PIN_CLK  0
#define PIN_DATA 34  //I2S麦克风引脚
#define READ_LEN (2 * 1024)
#define SAMPLING_FREQUENCY 44100
uint8_t BUFFER[READ_LEN] = {0};

uint8_t red = 0x00, green = 0x00, blue = 0x00;

uint16_t *adcBuffer = NULL;

const uint16_t FFTsamples = 256;  // 采样数
double vReal[FFTsamples];  //将采样保存到数组
double vImag[FFTsamples];
arduinoFFT FFT = arduinoFFT(vReal, vImag, FFTsamples, SAMPLING_FREQUENCY);  // 创建FFT对象

unsigned int sampling_period_us;

float dmax = 10000.0;

void i2sInit(){     //配置I2S
   i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_PDM),
    .sample_rate =  44100,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT, // is fixed at 12bit, stereo, MSB
    .channel_format = I2S_CHANNEL_FMT_ALL_RIGHT,
    .communication_format = I2S_COMM_FORMAT_I2S,
    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
    .dma_buf_count = 2,
    .dma_buf_len = 128,
   };

   i2s_pin_config_t pin_config;
   pin_config.bck_io_num   = I2S_PIN_NO_CHANGE;
   pin_config.ws_io_num    = PIN_CLK;
   pin_config.data_out_num = I2S_PIN_NO_CHANGE;
   pin_config.data_in_num  = PIN_DATA;
  
   
   i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
   i2s_set_pin(I2S_NUM_0, &pin_config);
   i2s_set_clk(I2S_NUM_0, 44100, I2S_BITS_PER_SAMPLE_16BIT, I2S_CHANNEL_MONO);
}

void mic_record_task (void* arg){     
  while(1){
    i2s_read_bytes(I2S_NUM_0,(char*)BUFFER,READ_LEN,(100/portTICK_RATE_MS));
    adcBuffer = (uint16_t *)BUFFER;
    fft();
    vTaskDelay(100 / portTICK_RATE_MS);
  }
}

void setup() {
  Serial.begin(115200);
  M5.begin();
  M5.Axp.ScreenBreath(9);    //屏幕亮度，最大12

  pixels.begin();
  pixels.setBrightness(50);   //LED亮度
  
  sampling_period_us = round(1000000 * (1.0 / SAMPLING_FREQUENCY)); //计算采样率

  i2sInit();
  xTaskCreatePinnedToCore(mic_record_task,"mic_record_task",2048,NULL,1,NULL,1);
}

void fft(){
  for (int i = 0; i < FFTsamples; i++) {
    unsigned long t = micros();
    vReal = adcBuffer;
    vImag = 0;
    while ((micros() - t) < sampling_period_us) ;
  }

  FFT.Windowing(FFT_WIN_TYP_HAMMING, FFT_FORWARD);  // 视图
  FFT.Compute(FFT_FORWARD); // FFT处理 复数计算
  FFT.ComplexToMagnitude(); // 复数与实数转换

  int nsamples = FFTsamples/2;

  for (int band = 0; band < nsamples; band++) {     //计算频段频率
    float d = vReal[band] / dmax;
    Serial.print(band);
    Serial.print(" : ");
    Serial.print((band * 1.0 * SAMPLING_FREQUENCY) / FFTsamples / 1000);
    Serial.print("kHz : ");
    Serial.println(d);
  }

  //15kHz
  if(vReal[87] / dmax > 0.3){
    red = 0xff;
  }else{
    red = 0x00;
  }
  //16kHz
  if(vReal[93] / dmax > 0.3){
    green = 0xff;
  }else{
    green = 0x00;
  }
  //17kHz
  if(vReal[99] / dmax > 0.3){
    blue = 0xff;
  }else{
    blue = 0x00;
  }

  uint32_t RGB888 = red << 16 | green << 8 | blue;
  Serial.println(RGB888);
  for(int i=0; i<6; i++) {
    pixels.setPixelColor(i, RGB888);
  }
   pixels.show();

  //RGB888转RGB565
  uint16_t RGB565 = (((RGB888 >> 19) & 0x1f) << 11) | (((RGB888 >> 10) & 0x3f) <<  5) | (((RGB888 >>  3) & 0x1f));
  M5.Lcd.fillScreen(RGB565);
}

void loop() {
}[/mw_shl_code]