Axel Boujon
Mini projet de FFT
Dependencies: mbed Grove_LCD_RGB_Backlight UIT_FFT_Real
Revision 0:c7f159ed0bc3, committed 2019-04-15
- Comitter:
- SBACCARI
- Date:
- Mon Apr 15 09:45:45 2019 +0000
- Child:
- 1:a806f3aacf1f
- Commit message:
- commiting to download
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Grove_LCD_RGB_Backlight.lib Mon Apr 15 09:45:45 2019 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/cmatz3/code/Grove_LCD_RGB_Backlight/#5ce38ef7a7db
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/UIT_FFT_Real.lib Mon Apr 15 09:45:45 2019 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/MikamiUitOpen/code/UIT_FFT_Real/#9649d0e2bb4a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Mon Apr 15 09:45:45 2019 +0000
@@ -0,0 +1,137 @@
+#include "mbed.h"
+#include "Grove_LCD_RGB_Backlight.h"
+#include "fftReal.hpp"
+
+Grove_LCD_RGB_Backlight ecran(P0_27, P0_28);
+AnalogIn micro(A1);
+DigitalOut myled(LED1);
+
+Ticker sampler;
+const int FFT_len = 256;
+int sampling_freq = 44000;
+float samples[FFT_len*2];
+int i = 0;
+
+void sampling_interrup()
+{
+ samples[i] = 1024*micro.read();
+ i++;
+ if (i >= FFT_len*2) {
+ sampler.detach();
+ }
+}
+
+void samplingBegin()
+{
+ // Reset sample buffer position and start callback at the sampling frequency
+ i = 0;
+ sampler.attach_us(&sampling_interrup, 1000000/sampling_freq);
+}
+
+bool samplingDone()
+{
+ return i >= FFT_len*2;
+}
+
+
+int main() {
+ char str[20];
+
+ // max 1 is set to the second FFT bin, because the first bin has the DC componenet of the signal.
+ int max1 = 2;
+ int max2 = 3;
+ float val = 0;
+
+ // CONFIG FFT
+ Mikami::Complex fft_bins[FFT_len];
+ Mikami::FftReal fft((int16_t)FFT_len);
+
+ // CONFIG ECRAN
+ ecran.setRGB(0, 255, 0);
+ ecran.clear();
+ ecran.locate(0, 1);
+
+ samplingBegin();
+
+ // The following loop, will do FFT and display highest detected frequency on the screen every 2s
+ // Commented sections, are debug mode. If uncommented, it will do FFT, display all the spectrum then restart, it will take about 10s + FFT_len/2 seconds
+
+ while(1) {
+ /*ecran.clear();
+ sprintf(str,"Sampling ...");
+ ecran.print(str);
+ ecran.setRGB(255, 0, 0);
+ wait(0.6);
+ ecran.setRGB(0, 0, 255);
+ wait(0.6);
+ ecran.setRGB(0, 255, 0);*/
+
+ // DO FFT
+ if (samplingDone())
+ {
+ /*ecran.locate(0, 0);
+ sprintf(str,"Sampling done");
+ ecran.print(str);
+ wait(1);*/
+
+ fft.Execute(samples,fft_bins);
+ wait(0.5);
+
+ /*ecran.clear();
+ sprintf(str,"FFT Done");
+ ecran.print(str);
+ wait(1);*/
+
+ // PRINT SPECTRUM
+ for(int j = 0;j < FFT_len/2 ;++j){
+ ecran.clear();
+ float mod = std::abs(fft_bins[j]);
+ float freq = j*sampling_freq/(FFT_len*1000);
+
+ /*sprintf(str,"%d.Freq = %.2f kHz", j,freq );
+ ecran.locate(0,1);
+ ecran.print(str);
+
+ sprintf(str,"%d.Mag = %.2f", j, mod );
+ ecran.locate(0,0);
+ ecran.print(str);*/
+
+ if( (j>5)and mod >= std::abs(fft_bins[max1]) ){
+ max1 = j;
+ }
+ /*else if ( (j>3) and (std::abs(fft_bins[j]) >= std::abs(fft_bins[max2])) and (std::abs(fft_bins[j]) < std::abs(fft_bins[max1]))){
+ max2 = j;
+ }
+ wait(1);*/
+ }
+
+ val = max1*sampling_freq/(FFT_len*1000);
+ float mod = std::abs(fft_bins[max1]);
+
+ /*sprintf(str,"%max1= %.2f", mod );
+ ecran.locate(0,0);
+ ecran.print(str);*/
+
+ ecran.clear();
+ sprintf(str,"max= %.2f kHz", val );
+ ecran.locate(0,0);
+ ecran.print(str);
+ wait(2);
+
+ /*val = max2*sampling_freq/(FFT_len*1000);
+ sprintf(str,"max 2 = %.2f kHz", val);
+ ecran.locate(0,1);
+ ecran.print(str);
+ wait(2);*/
+
+ samplingBegin();
+
+ }
+
+ /* // DEBUG SCREEN
+ ecran.clear();
+ myled = !myled;
+ sprintf(str,"Waiting ...");
+ ecran.print(str);*/
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Mon Apr 15 09:45:45 2019 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/mbed_official/code/mbed/builds/3a7713b1edbc \ No newline at end of file