Hello.
i want to ask and please give me some advice
I use FFT code (as I attached below) to measure sound frequency. in the code, there are "Samples" and "sampling_frequency". I use arduino r3 and it can only use a maximum of 128 samples. i want to increase the samples into around 1000 or 2000 samples, should I use an external SRAM or upgrade the arduino into mega? i read some article said its gonna be tricky and maybe hard for some users.
do you have any suggestion about this?
thank you
#include "arduinoFFT.h"
#define SAMPLES 128 //SAMPLES-pt FFT. Must be a base 2 number. Max 128 for Arduino Uno.
#define SAMPLING_FREQUENCY 2028 //Ts = Based on Nyquist, must be 2 times the highest expected frequency.
arduinoFFT FFT = arduinoFFT();
unsigned int samplingPeriod;
unsigned long microSeconds;
double vReal[SAMPLES]; //create vector of size SAMPLES to hold real values
double vImag[SAMPLES]; //create vector of size SAMPLES to hold imaginary values
void setup()
{
Serial.begin(115200); //Baud rate for the Serial Monitor
samplingPeriod = round(1000000*(1.0/SAMPLING_FREQUENCY)); //Period in microseconds
}
void loop()
{
/*Sample SAMPLES times*/
for(int i=0; i<SAMPLES; i++)
{
microSeconds = micros(); //Returns the number of microseconds since the Arduino board began running the current script.
vReal[i] = analogRead(0); //Reads the value from analog pin 0 (A0), quantize it and save it as a real term.
vImag[i] = 0; //Makes imaginary term 0 always
/*remaining wait time between samples if necessary*/
while(micros() < (microSeconds + samplingPeriod))
{
//do nothing
}
}
/*Perform FFT on samples*/
FFT.Windowing(vReal, SAMPLES, FFT_WIN_TYP_HAMMING, FFT_FORWARD);
FFT.Compute(vReal, vImag, SAMPLES, FFT_FORWARD);
FFT.ComplexToMagnitude(vReal, vImag, SAMPLES);
/*Find peak frequency and print peak*/
double peak = FFT.MajorPeak(vReal, SAMPLES, SAMPLING_FREQUENCY);
Serial.print(millis());
Serial.print(",");
Serial.println(peak); //Print out the most dominant frequency.
}