main.cpp

00001 #define SAMPLE_RATE   48000
00002 
00003 
00004 #include "mbed.h"
00005 #include "adc.h"
00006 #include "PololuLedStrip.h"
00007 
00008 PololuLedStrip ledStrip(p8);
00009 
00010 #define LED_COUNT 60
00011 rgb_color colors[LED_COUNT];
00012 
00013 Serial pc(USBTX,USBRX);
00014 
00015 //extern "C" void cr4_fft_256_stm32(void *pssOUT, void *pssIN, uint16_t Nbin);
00016 extern "C" void fftR4(short *y, short *x, int N);
00017 
00018 //use the LED as a bargraph
00019 DigitalOut l1(LED1);
00020 DigitalOut l2(LED2);
00021 DigitalOut l3(LED3);
00022 DigitalOut l4(LED4);
00023 
00024 //set up a timer for timing FFT's
00025 Timer timer;
00026 
00027 //Used to change colour of LED strips
00028 //int testX = 0;
00029 
00030 //Set up filesystem so we can write some useful files
00031 
00032 LocalFileSystem local("local");              
00033 FILE *fp;
00034 
00035 //Set up a global buffer for audio data so interrupt can access it
00036 int Counter = 0;
00037 int16_t Buffer[5000];
00038 int16_t VoltageBuffer[5000];
00039 
00040 //Initialise ADC to maximum SAMPLE_RATE and cclk divide set to 1
00041 ADC adc(SAMPLE_RATE, 1);
00042 
00043 int colourVoltage=0;
00044 
00045 
00046 
00047 //Our interrupt handler for audio sampling
00048 void sample_ADC(int chan, uint32_t value) {
00049     
00050    float s;
00051    s = adc.read(p20); 
00052    int16_t b = (s -2048)*16;
00053    Buffer[Counter] = b;
00054    
00055    Counter += 1;
00056     /* bar graph */
00057      
00058     int g = abs(s-2048);
00059     l1 = g > 0.1f*2048;
00060     l2 = g > 0.3f*2048;
00061     l3 = g > 0.6f*2048;
00062     l4 = g > 0.8f*2048;
00063 }
00064 
00065 
00066     
00067     
00068     
00069     
00070 int main() {
00071     
00072 while (1){
00073     
00074     //Prepare for burst mode on all ADC pins and set up interrupt handler (using ADC library from Simon Blandford
00075     adc.append(sample_ADC);
00076     adc.startmode(0,0);
00077     adc.burst(1);
00078     adc.setup(p20,1);
00079     //introduce a delay as initial waveform has bias whilst decoupling cap charges
00080     wait(0.05);
00081     //start the interrupt and wait for about 4096 samples
00082     adc.interrupt_state(p20,1);
00083     wait(0.05);
00084     
00085         //Finsh up - Unset pin 20
00086         adc.interrupt_state(p20,0);
00087         adc.setup(p20,0);
00088         int actual_rate = adc.actual_sample_rate();
00089 //now lets try mellen fft-------------------------
00090         timer.reset();
00091         timer.start();
00092         #define MN 1024 /*Number of points*/
00093         short mx[MN*2]; // input data 16 bit, 4 byte aligned  x0r,x0i,x1r,x1i,....
00094         short my[MN*2]; // output data 16 bit,4 byte aligned  y0r,y0i,y1r,y1i,....
00095         float mz[MN*2]; // to store the final result
00096         for (int i=0;i<MN*2;i++) mx[i]=0;
00097         for (int i=0;i<MN*2;i++) mz[i]=0;
00098         for (int i=0;i<MN;i=i+1)
00099             { mx[i*2]=Buffer[i];}
00100         //printf("Mellen set up took %i\n",timer.read_us());
00101         //call functions
00102         timer.reset();
00103         timer.start();
00104         fftR4(my, mx, MN);
00105         //printf("Mellen fft took %i\n",timer.read_us());
00106 //FILE* mlog = fopen("/local/mellen.csv","w");
00107         
00108         //now write a CSV file to filesytem of frequency vs amplitude
00109         for (int i=0; i<MN; i=i+2)
00110         {
00111           //  fprintf(mlog, "%d: %d -> %d\n", i, mx[i], my[i]);
00112             //fprintf(mlog, "%d,%f\n", int(actual_rate/MN/2*i),sqrt(float(   (my[i]*my[i])  +(my[i+1]*my[i+1])     ) )   );          
00113         
00114         mz[i]=sqrt(float(   (my[i]*my[i])  +(my[i+1]*my[i+1])     ) ) ;
00115          //fprintf(mlog, "%f\n", mz[i]  );
00116         }
00117        
00118         
00119         // detect the change of input frequency ******************************
00120     float maxFreq=0;
00121     float max=0;
00122     for (int i=2;i<512;i=i+1){
00123            
00124         if(mz[i]>max){
00125             max = mz[i];
00126             maxFreq=i;
00127             }//end if
00128         
00129         }//end for
00130     //fprintf(mlog, "%d\n",maxFreq  );
00131     
00132     int maxVoltage=0;
00133     for (int i=0;i<512;i=i+1){
00134            
00135         if(mx[i]>maxVoltage){
00136             maxVoltage = mx[i];
00137            
00138             }//end if
00139         }//end for
00140     
00141 pc.printf(" the max = %f\n",max );
00142 pc.printf(" the maxFreq = %f\n",maxFreq );
00143 pc.printf(" the colourValtage = %d\n", maxVoltage );
00144 
00145 
00146         /*for (int i = 0; i < LED_COUNT; i++){
00147         colors[i] = (rgb_color){ 0, 0, 0 };  
00148         } 
00149         
00150         if (maxFreq>60) maxFreq=60; // Limiting Length
00151         
00152          for (int i = 0; i < maxFreq; i++){
00153             colors[i] = (rgb_color){ abs(maxVoltage/11),abs(255-(maxVoltage/11)) ,abs(255-(maxVoltage/11)+50)  };
00154             }   
00155              ledStrip.write(colors, LED_COUNT);*/
00156             int actualFreq= (actual_rate/MN/2*maxFreq);
00157             pc.printf(" actualFreq = %d\n", actualFreq );
00158             
00159             
00160             //wait_ms(10);
00161             
00162             /*if (maxFreq>30){
00163             //testX=200;
00164             for (int i = 0; i < LED_COUNT; i++){
00165             colors[i] = (rgb_color){ 0, 20, 200 };
00166             }
00167             }
00168 
00169         if ((maxFreq>22)&&(maxFreq<30)){// if frequency bigger than 966Hz
00170             //testX= 10;
00171             for (int i = 0; i < LED_COUNT; i++){
00172             colors[i] = (rgb_color){ 250, 0, 0 };
00173             
00174             }
00175             }
00176         if (maxFreq<22){
00177             //testX=200;
00178             for (int i = 0; i < LED_COUNT; i++){
00179             colors[i] = (rgb_color){ 0, 250, 0 };
00180             }
00181             }*/
00182 
00183     
00184      
00185        
00186         
00187             
00188             
00189             //-----------
00190         
00191         
00192         //fclose(mlog);    
00193   Counter = 0;
00194         }// end while (1)
00195         
00196     
00197 }