Arduino.ru

#include "arduinoFFT.h"
#include <LiquidCrystal.h>
LiquidCrystal lcd(PA0, PA1, PA2, PA3, PA4, PA5);
#define SAMPLES 128 //Must be a power of 2, # of bins = samples/by 2 = 64
#define SAMPLING_FREQUENCY 1000 //Hz, must be less than 10000 due to ADC
//////////////////////
const int numReadings = 10;
int readings[numReadings];      // the readings from the analog input
int readIndex = 0;              // the index of the current reading
int total = 0;                  // the running total
int average = 0;                // the average
//////////////////////
int i;
arduinoFFT FFT = arduinoFFT();

unsigned int sampling_period_us;
unsigned long microseconds;

double vReal[SAMPLES];
double vImag[SAMPLES];

void setup() {
  Serial.begin(115200);
  lcd.begin(16, 2);
  sampling_period_us = round(1000000 * (1.0 / SAMPLING_FREQUENCY));
  //////////////////////
  for (int thisReading = 0; thisReading < numReadings; thisReading++) {
    readings[thisReading] = 0;
  }
    /////////////////////
  }

  void loop() {

    /*SAMPLING*/
    for (int i = 0; i < SAMPLES; i++)
    {
      microseconds = micros();    //Overflows after around 70 minutes!

      // vReal[i] = analogRead(0);
      vReal[i] = analogRead(PA7);
      vImag[i] = 0;

      while (micros() < (microseconds + sampling_period_us)) {
      }
    }

    /*FFT*/
    FFT.Windowing(vReal, SAMPLES, FFT_WIN_TYP_HAMMING, FFT_FORWARD);
    FFT.Compute(vReal, vImag, SAMPLES, FFT_FORWARD);
    FFT.ComplexToMagnitude(vReal, vImag, SAMPLES);
    double peak = FFT.MajorPeak(vReal, SAMPLES, SAMPLING_FREQUENCY);

    /*PRINT RESULTS*/
    // Serial.println(peak);     //Print out what frequency is the most dominant.

    //for (int i = 0; i < (SAMPLES / 2); i++)
    //   for (int i = 0; i < (36); i++)
    {
      /*View all these three lines in serial terminal to see which frequencies has which amplitudes*/

      //Serial.print((i * 1.0 * SAMPLING_FREQUENCY) / SAMPLES, 1);

      //Serial.print(" ");
     // Serial.println(vReal[35], 1);    //View only this line in serial plotter to visualize the bins

    }
  ///////////////////
 // subtract the last reading:
  total = total - readings[readIndex];
  // read from the sensor:
  //readings[readIndex] = analogRead(inputPin);
   readings[readIndex] = (vReal[35], 1);
  // add the reading to the total:
  total = total + readings[readIndex];
  // advance to the next position in the array:
  readIndex = readIndex + 1;

  // if we're at the end of the array...
  if (readIndex >= numReadings) {
    // ...wrap around to the beginning:
    readIndex = 0;
  }

  // calculate the average:
  average = total / numReadings;
  // send it to the computer as ASCII digits
  Serial.println(average);
  delay(1);        // delay in between reads for stability
  ///////////////////
    //delay(1000);  //Repeat the process every second OR:
    // while(1);       //Run code once
    lcd.setCursor(0, 0);
    lcd.print("V");
    lcd.setCursor(3, 0);
    lcd.print(vReal[35], 1); //
    lcd.setCursor(0, 1);
    lcd.print(peak); // frequency
   
  }