91 lines
2.2 KiB
Arduino
91 lines
2.2 KiB
Arduino
/* This example shows how to use the FFT library with a circuit playground express.
|
|
*
|
|
* The LEDs will map around the circle when frequencies between FREQ_MIN and FREQ_MAX are detected
|
|
*/
|
|
|
|
#include <Adafruit_CircuitPlayground.h>
|
|
#include "Adafruit_ZeroFFT.h"
|
|
|
|
//this must be a power of 2
|
|
#define DATA_SIZE 256
|
|
|
|
#define NUM_PIXELS 12
|
|
|
|
//the sample rate
|
|
#define FS 22000
|
|
|
|
//the lowest frequency that will register on the meter
|
|
#define FREQ_MIN 600
|
|
|
|
//the highest frequency that will register on the meter
|
|
#define FREQ_MAX 3000
|
|
|
|
#define MIN_INDEX FFT_INDEX(FREQ_MIN, FS, DATA_SIZE)
|
|
#define MAX_INDEX FFT_INDEX(FREQ_MAX, FS, DATA_SIZE)
|
|
|
|
#define SCALE_FACTOR 32
|
|
|
|
int16_t pixelData[NUM_PIXELS];
|
|
int16_t inputData[DATA_SIZE];
|
|
|
|
// the setup routine runs once when you press reset:
|
|
void setup() {
|
|
CircuitPlayground.begin();
|
|
}
|
|
|
|
void loop() {
|
|
CircuitPlayground.mic.capture(inputData, DATA_SIZE);
|
|
|
|
/*******************************
|
|
* REMOVE DC OFFSET
|
|
******************************/
|
|
int32_t avg = 0;
|
|
int16_t *ptr = inputData;
|
|
for(int i=0; i<DATA_SIZE; i++) avg += *ptr++;
|
|
avg = avg/DATA_SIZE;
|
|
|
|
ptr = inputData;
|
|
for(int i=0; i<DATA_SIZE; i++){
|
|
*ptr -= avg;
|
|
*ptr++ = *ptr*SCALE_FACTOR;
|
|
}
|
|
|
|
//run the FFT
|
|
ZeroFFT(inputData, DATA_SIZE);
|
|
|
|
//set all to 0
|
|
memset(pixelData, 0, NUM_PIXELS*sizeof(int16_t));
|
|
|
|
//downsample into NUM_PIXELS bins
|
|
for(int i=MIN_INDEX; i<MAX_INDEX; i++){
|
|
int ix = map(i, MIN_INDEX, MAX_INDEX, 0, NUM_PIXELS);
|
|
pixelData[ix] += inputData[i];
|
|
}
|
|
|
|
//display the data
|
|
for(int i=0; i<NUM_PIXELS; i++)
|
|
CircuitPlayground.strip.setPixelColor(i, Wheel(pixelData[i]));
|
|
|
|
CircuitPlayground.strip.show();
|
|
}
|
|
|
|
// Input a value 0 to 255 to get a color value.
|
|
// The colours are a transition r - g - b - back to r.
|
|
// values below 20 will not register
|
|
uint32_t Wheel(byte WheelPos) {
|
|
if(WheelPos < 20) {
|
|
return CircuitPlayground.strip.Color(0, 0, 0);
|
|
}
|
|
else if(WheelPos < 85) {
|
|
return CircuitPlayground.strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
|
|
}
|
|
else if(WheelPos < 170) {
|
|
WheelPos -= 85;
|
|
return CircuitPlayground.strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
|
|
}
|
|
else {
|
|
WheelPos -= 170;
|
|
return CircuitPlayground.strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
|
|
}
|
|
}
|