Diff: main.cpp

Revision:

0:c7f159ed0bc3

Child:

1:a806f3aacf1f

--- /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);*/
+    }
+}