/* ESP8266/32 Audio Spectrum Analyser on an SSD1306/SH1106 Display
* The MIT License (MIT) Copyright (c) 2017 by David Bird.
* The formulation and display of an AUdio Spectrum using an ESp8266 or ESP32 and SSD1306 or SH1106 OLED Display using a Fast Fourier Transform
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge,
* publish, distribute, but not to use it commercially for profit making or to sub-license and/or to sell copies of the Software or to
* permit persons to whom the Software is furnished to do so, subject to the following conditions:
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
* See more at http://dsbird.org.uk
*/
// https://github.com/tobozo/ESP32-8-Octave-Audio-Spectrum-Display/tree/wrover-kit
// https://github.com/G6EJD/ESP32-8266-Audio-Spectrum-Display
// https://github.com/kosme/arduinoFFT
#include "arduinoFFT.h" // Standard Arduino FFT library
arduinoFFT FFT = arduinoFFT();
#include <M5Stack.h>
#define SAMPLES 512 // Must be a power of 2
#define SAMPLING_FREQUENCY 40000
// Hz, must be 40000 or less due to ADC conversion time.
// Determines maximum frequency that can be analysed by the FFT Fmax=sampleF/2.
int micpin = 34; //change this to 36 if you are using the fc-04
struct eqBand {
const char *freqname;
uint16_t amplitude;
int peak;
int lastpeak;
uint16_t lastval;
unsigned long lastmeasured;
};
eqBand audiospectrum[8] = {
//Adjust the amplitude values to fit your microphone
{ "125Hz", 500, 0, 0, 0, 0},
{ "250Hz", 200, 0, 0, 0, 0},
{ "500Hz", 200, 0, 0, 0, 0},
{ "1KHz", 200, 0, 0, 0, 0},
{ "2KHz", 200, 0, 0, 0, 0},
{ "4KHz", 100, 0, 0, 0, 0},
{ "8KHz", 100, 0, 0, 0, 0},
{ "16KHz", 50, 0, 0, 0, 0}
};
unsigned int sampling_period_us;
unsigned long microseconds;
double vReal[SAMPLES];
double vImag[SAMPLES];
unsigned long newTime, oldTime;
uint16_t tft_width = 320; // ILI9341_TFTWIDTH;
uint16_t tft_height = 240; // ILI9341_TFTHEIGHT;
uint8_t bands = 8;
uint8_t bands_width = floor( tft_width / bands );
uint8_t bands_pad = bands_width - 10;
uint16_t colormap[255]; // color palette for the band meter (pre-fill in setup)
void setup() {
M5.begin();
dacWrite(25, 0); // Speaker OFF
M5.Lcd.fillScreen(TFT_BLACK);
M5.Lcd.setTextColor(YELLOW, BLACK);
M5.Lcd.setTextSize(1);
M5.Lcd.setRotation(0);
sampling_period_us = round(1000000 * (1.0 / SAMPLING_FREQUENCY));
delay(2000);
for(uint8_t i=0;i<tft_height;i++) {
colormap[i] = M5.Lcd.color565(tft_height-i*.5, i*1.1, 0);
}
for (byte band = 0; band <= 7; band++) {
M5.Lcd.setCursor(bands_width*band + 2, 0);
M5.Lcd.print(audiospectrum[band].freqname);
}
}
void loop() {
for (int i = 0; i < SAMPLES; i++) {
newTime = micros()-oldTime;
oldTime = newTime;
vReal[i] = analogRead(micpin); // A conversion takes about 1uS on an ESP32
vImag[i] = 0;
while (micros() < (newTime + sampling_period_us)) {
// do nothing to wait
}
}
FFT.Windowing(vReal, SAMPLES, FFT_WIN_TYP_HAMMING, FFT_FORWARD);
FFT.Compute(vReal, vImag, SAMPLES, FFT_FORWARD);
FFT.ComplexToMagnitude(vReal, vImag, SAMPLES);
for (int i = 2; i < (SAMPLES/2); i++){
// Don't use sample 0 and only first SAMPLES/2 are usable.
// Each array eleement represents a frequency and its value the amplitude.
if (vReal[i] > 1500) { // Add a crude noise filter, 10 x amplitude or more
byte bandNum = getBand(i);
if(bandNum!=8) {
displayBand(bandNum, (int)vReal[i]/audiospectrum[bandNum].amplitude);
}
}
}
long vnow = millis();
for (byte band = 0; band <= 7; band++) {
// auto decay every 50ms on low activity bands
if(vnow - audiospectrum[band].lastmeasured > 50) {
displayBand(band, audiospectrum[band].lastval>4 ? audiospectrum[band].lastval-4 : 0);
}
if (audiospectrum[band].peak > 0) {
audiospectrum[band].peak -= 2;
if(audiospectrum[band].peak<=0) {
audiospectrum[band].peak = 0;
}
}
// only draw if peak changed
if(audiospectrum[band].lastpeak != audiospectrum[band].peak) {
// delete last peak
M5.Lcd.drawFastHLine(bands_width*band,tft_height-audiospectrum[band].lastpeak,bands_pad,BLACK);
audiospectrum[band].lastpeak = audiospectrum[band].peak;
M5.Lcd.drawFastHLine(bands_width*band, tft_height-audiospectrum[band].peak,
bands_pad, colormap[tft_height-audiospectrum[band].peak]);
}
}
}
void displayBand(int band, int dsize){
uint16_t hpos = bands_width*band;
int dmax = 200;
if(dsize>tft_height-10) {
dsize = tft_height-10; // leave some hspace for text
}
if(dsize < audiospectrum[band].lastval) {
// lower value, delete some lines
M5.Lcd.fillRect(hpos, tft_height-audiospectrum[band].lastval,
bands_pad, audiospectrum[band].lastval - dsize, BLACK);
}
if (dsize > dmax) dsize = dmax;
for (int s = 0; s <= dsize; s=s+4){
M5.Lcd.drawFastHLine(hpos, tft_height-s, bands_pad, colormap[tft_height-s]);
}
if (dsize > audiospectrum[band].peak) {
audiospectrum[band].peak = dsize;
}
audiospectrum[band].lastval = dsize;
audiospectrum[band].lastmeasured = millis();
}
byte getBand(int i) {
if (i<=2 ) return 0; // 125Hz
if (i >3 && i<=5 ) return 1; // 250Hz
if (i >5 && i<=7 ) return 2; // 500Hz
if (i >7 && i<=15 ) return 3; // 1000Hz
if (i >15 && i<=30 ) return 4; // 2000Hz
if (i >30 && i<=53 ) return 5; // 4000Hz
if (i >53 && i<=200 ) return 6; // 8000Hz
if (i >200 ) return 7; // 16000Hz
return 8;
}
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