aboutsummaryrefslogtreecommitdiffstats
path: root/src/libs/arduinoFFT-develop/Examples/FFT_01
diff options
context:
space:
mode:
Diffstat (limited to 'src/libs/arduinoFFT-develop/Examples/FFT_01')
-rw-r--r--src/libs/arduinoFFT-develop/Examples/FFT_01/FFT_01.ino119
1 files changed, 119 insertions, 0 deletions
diff --git a/src/libs/arduinoFFT-develop/Examples/FFT_01/FFT_01.ino b/src/libs/arduinoFFT-develop/Examples/FFT_01/FFT_01.ino
new file mode 100644
index 00000000..22b5024a
--- /dev/null
+++ b/src/libs/arduinoFFT-develop/Examples/FFT_01/FFT_01.ino
@@ -0,0 +1,119 @@
+/*
+
+ Example of use of the FFT libray
+
+ Copyright (C) 2014 Enrique Condes
+ Copyright (C) 2020 Bim Overbohm (header-only, template, speed improvements)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+/*
+ In this example, the Arduino simulates the sampling of a sinusoidal 1000 Hz
+ signal with an amplitude of 100, sampled at 5000 Hz. Samples are stored
+ inside the vReal array. The samples are windowed according to Hamming
+ function. The FFT is computed using the windowed samples. Then the magnitudes
+ of each of the frequencies that compose the signal are calculated. Finally,
+ the frequency with the highest peak is obtained, being that the main frequency
+ present in the signal.
+*/
+
+#include "arduinoFFT.h"
+
+/*
+These values can be changed in order to evaluate the functions
+*/
+const uint16_t samples = 64; //This value MUST ALWAYS be a power of 2
+const double signalFrequency = 1000;
+const double samplingFrequency = 5000;
+const uint8_t amplitude = 100;
+
+/*
+These are the input and output vectors
+Input vectors receive computed results from FFT
+*/
+double vReal[samples];
+double vImag[samples];
+
+/* Create FFT object */
+ArduinoFFT<double> FFT = ArduinoFFT<double>(vReal, vImag, samples, samplingFrequency);
+
+#define SCL_INDEX 0x00
+#define SCL_TIME 0x01
+#define SCL_FREQUENCY 0x02
+#define SCL_PLOT 0x03
+
+void setup()
+{
+ Serial.begin(115200);
+ Serial.println("Ready");
+}
+
+void loop()
+{
+ /* Build raw data */
+ double cycles = (((samples-1) * signalFrequency) / samplingFrequency); //Number of signal cycles that the sampling will read
+ for (uint16_t i = 0; i < samples; i++)
+ {
+ vReal[i] = int8_t((amplitude * (sin((i * (TWO_PI * cycles)) / samples))) / 2.0);/* Build data with positive and negative values*/
+ //vReal[i] = uint8_t((amplitude * (sin((i * (twoPi * cycles)) / samples) + 1.0)) / 2.0);/* Build data displaced on the Y axis to include only positive values*/
+ vImag[i] = 0.0; //Imaginary part must be zeroed in case of looping to avoid wrong calculations and overflows
+ }
+ /* Print the results of the simulated sampling according to time */
+ Serial.println("Data:");
+ PrintVector(vReal, samples, SCL_TIME);
+ FFT.windowing(FFTWindow::Hamming, FFTDirection::Forward); /* Weigh data */
+ Serial.println("Weighed data:");
+ PrintVector(vReal, samples, SCL_TIME);
+ FFT.compute(FFTDirection::Forward); /* Compute FFT */
+ Serial.println("Computed Real values:");
+ PrintVector(vReal, samples, SCL_INDEX);
+ Serial.println("Computed Imaginary values:");
+ PrintVector(vImag, samples, SCL_INDEX);
+ FFT.complexToMagnitude(); /* Compute magnitudes */
+ Serial.println("Computed magnitudes:");
+ PrintVector(vReal, (samples >> 1), SCL_FREQUENCY);
+ double x = FFT.majorPeak();
+ Serial.println(x, 6);
+ while(1); /* Run Once */
+ // delay(2000); /* Repeat after delay */
+}
+
+void PrintVector(double *vData, uint16_t bufferSize, uint8_t scaleType)
+{
+ for (uint16_t i = 0; i < bufferSize; i++)
+ {
+ double abscissa;
+ /* Print abscissa value */
+ switch (scaleType)
+ {
+ case SCL_INDEX:
+ abscissa = (i * 1.0);
+ break;
+ case SCL_TIME:
+ abscissa = ((i * 1.0) / samplingFrequency);
+ break;
+ case SCL_FREQUENCY:
+ abscissa = ((i * 1.0 * samplingFrequency) / samples);
+ break;
+ }
+ Serial.print(abscissa, 6);
+ if(scaleType==SCL_FREQUENCY)
+ Serial.print("Hz");
+ Serial.print(" ");
+ Serial.println(vData[i], 4);
+ }
+ Serial.println();
+}