Subversion Repositories svnkaklik

Rev

Rev 558 | Go to most recent revision | Blame | Last modification | View Log | Download

///////////////////////////////////////////////////////////////////////////////////
//                        A small demo of sonar.
// Program allow distance measuring.
// Uses cross-correlation algorithm to find echos
//
// Author: kaklik  (kaklik@mlab.cz)
//
///////////////////////////////////////////////////////////////////////////////////

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sched.h>
#include <errno.h>
#include <getopt.h>
#include <alsa/asoundlib.h>
#include <sys/time.h>
#include <math.h>

static char *device = "plughw:0,0";                     /* playback device */
static snd_pcm_format_t format = SND_PCM_FORMAT_S16;    /* sample format */
static unsigned int rate = 98000;                       /* stream rate */
static unsigned int buffer_time = 500000;               /* ring buffer length in us */
static unsigned int period_time = 100000;               /* period time in us */
static int resample = 1;                                /* enable alsa-lib resampling */
static int period_event = 0;                            /* produce poll event after each period */

#define SOUND_SPEED     340
#define SIGNAL_SAMPLES 100000
#define CHIRP_OFFSET    0 

unsigned int chirp_size;

int period=0;
int cperiod=0;
int chirp[100000];
short signal[1000000];          // record 6s of input samples

static snd_pcm_sframes_t buffer_size;   // size of buffer at sound card
static snd_pcm_sframes_t period_size;   //samples per frame
static snd_output_t *output = NULL;

static int set_hwparams(snd_pcm_t *handle, snd_pcm_hw_params_t *params, unsigned int channels)
{
        unsigned int rrate;
        snd_pcm_uframes_t size;
        int err, dir;

        /* choose all parameters */
        err = snd_pcm_hw_params_any(handle, params);
        if (err < 0) {
                printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));
                return err;
        }
        /* set hardware resampling */
        err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);
        if (err < 0) {
                printf("Resampling setup failed for playback: %s\n", snd_strerror(err));
                return err;
        }
        /* set the interleaved read/write format */
        err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
        if (err < 0) {
                printf("Access type not available for playback: %s\n", snd_strerror(err));
                return err;
        }
        /* set the sample format */
        err = snd_pcm_hw_params_set_format(handle, params, format);
        if (err < 0) {
                printf("Sample format not available for playback: %s\n", snd_strerror(err));
                return err;
        }
        /* set the count of channels */
        err = snd_pcm_hw_params_set_channels(handle, params, channels);
        if (err < 0) {
                printf("Channels count (%i) not available for playbacks: %s\n", channels, snd_strerror(err));
                return err;
        }
        /* set the stream rate */
        rrate = rate;
        err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);
        if (err < 0) {
                printf("Rate %iHz not available for playback: %s\n", rate, snd_strerror(err));
                return err;
        }
        if (rrate != rate) {
                printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
                return -EINVAL;
        }
        else printf("Rate set to %i Hz\n", rate, err); 
        /* set the buffer time */
        err = snd_pcm_hw_params_set_buffer_time_near(handle, params, &buffer_time, &dir);
        if (err < 0) {
                printf("Unable to set buffer time %i for playback: %s\n", buffer_time, snd_strerror(err));
                return err;
        }
        err = snd_pcm_hw_params_get_buffer_size(params, &size);
        if (err < 0) {
                printf("Unable to get buffer size for playback: %s\n", snd_strerror(err));
                return err;
        }
        buffer_size = size;
        /* set the period time */
        err = snd_pcm_hw_params_set_period_time_near(handle, params, &period_time, &dir);
        if (err < 0) {
                printf("Unable to set period time %i for playback: %s\n", period_time, snd_strerror(err));
                return err;
        }
        err = snd_pcm_hw_params_get_period_size(params, &size, &dir);
        if (err < 0) {
                printf("Unable to get period size for playback: %s\n", snd_strerror(err));
                return err;
        }
        period_size = size;
        /* write the parameters to device */
        err = snd_pcm_hw_params(handle, params);
        if (err < 0) {
                printf("Unable to set hw params for playback: %s\n", snd_strerror(err));
                return err;
        }
        return 0;
}

static int set_swparams(snd_pcm_t *handle, snd_pcm_sw_params_t *swparams)
{
        int err;

        /* get the current swparams */
        err = snd_pcm_sw_params_current(handle, swparams);
        if (err < 0) {
                printf("Unable to determine current swparams for playback: %s\n", snd_strerror(err));
                return err;
        }
        /* start the transfer when the buffer is almost full: */
        /* (buffer_size / avail_min) * avail_min */
        err = snd_pcm_sw_params_set_start_threshold(handle, swparams, (buffer_size / period_size) * period_size);
        if (err < 0) {
                printf("Unable to set start threshold mode for playback: %s\n", snd_strerror(err));
                return err;
        }
        /* allow the transfer when at least period_size samples can be processed */
        /* or disable this mechanism when period event is enabled (aka interrupt like style processing) */
        err = snd_pcm_sw_params_set_avail_min(handle, swparams, period_event ? buffer_size : period_size);
        if (err < 0) {
                printf("Unable to set avail min for playback: %s\n", snd_strerror(err));
                return err;
        }
        /* enable period events when requested */
        if (period_event) {
                err = snd_pcm_sw_params_set_period_event(handle, swparams, 1);
                if (err < 0) {
                        printf("Unable to set period event: %s\n", snd_strerror(err));
                        return err;
                }
        }
        /* write the parameters to the playback device */
        err = snd_pcm_sw_params(handle, swparams);
        if (err < 0) {
                printf("Unable to set sw params for playback: %s\n", snd_strerror(err));
                return err;
        }
        return 0;
}

struct async_private_data {
        signed short *samples;
        snd_pcm_channel_area_t *areas;
        unsigned int period;
};


////// SIGNAL GENERATION STUFF
/*int linear_chirp(int *pole, int delka_pole){  // vygeneruje linearni chirp a vzorky ulozi do pole

static const float f0 = 0.0001;
static const float k = 0.00001;

int t;

//  if((spozdeni+delka) < delka_pole)
    for(t=0;t < delka_pole;t++) pole[t] = round ( 10000*sin(2*M_PI*(t+faze)*(f0+(k/2)*(t+faze))) );
    faze +=t;
//  else return 0;

}*/

// vygeneruje linearni chirp a vzorky ulozi do pole
unsigned int linear_windowed_chirp(unsigned int *pole, unsigned int delka_pole,unsigned int offset)
{
unsigned int maxval = (1 << (snd_pcm_format_width(format) - 1)) - 1;

static const float f0 = 1000;           //starting frequency
static const float fmax = 7000;         //ending frequency
static const float Tw = 0.002;
static float k;

unsigned int n=0;
double t;
unsigned int perioda;

  k=2*(fmax-f0)/Tw;
  perioda = rate*Tw; 

  for(n=0;n<=perioda;n++){
     t = (double) n/ (double)rate;
     pole[n+offset] = (short) floor( (0.35875 - 0.48829*cos(2*M_PI*t*1/Tw) + 0.14128*cos(2*M_PI*2*t*1/Tw) - 0.01168*cos(2*M_PI*3*t*1/Tw))*maxval*sin(2*M_PI*(t)*(f0+(k/2)*(t))) );
  }
  return (perioda+offset);
}

// generate sine samples and store
int sine(unsigned int *pole, unsigned int delka_pole)
{
unsigned int maxval = (1 << (snd_pcm_format_width(format) - 1)) - 1;
unsigned int n;
double t;

  for(n=0;n < delka_pole;n++){
    t = 440.0 * (double) n/ (double)rate;
    pole[n] = (short) floor(maxval*sin(2*M_PI*t));
  }
}
//// generate simple sine ping
unsigned int sine_ping(unsigned int *pole, unsigned int delka_pole,unsigned int offset, double frequency)
{
unsigned int maxval = (1 << (snd_pcm_format_width(format) - 1)) - 1;
unsigned int n;
double t;

  for(n=0;n < delka_pole;n++){
    t = frequency * (double) n/ (double)rate;
    pole[n] = (short) floor(maxval*sin(2*M_PI*t));
  }
}

/////////// CALL BACK STUFF ///////////////////
static void async_playback_callback(snd_async_handler_t *ahandler)
{
        snd_pcm_t *handle = snd_async_handler_get_pcm(ahandler);
        snd_pcm_sframes_t avail;
        int err;
        
        avail = snd_pcm_avail_update(handle);
        while ((avail >= period_size) && ((period*period_size) < chirp_size) ) {

                err = snd_pcm_writei(handle, (chirp+period*period_size), period_size);
                if (err < 0) {
                        printf("Write error: %s\n", snd_strerror(err));
                        exit(EXIT_FAILURE);
                }
                if (err != period_size) {
                        printf("Write error: written %i expected %li\n", err, period_size);
                        exit(EXIT_FAILURE);
                }
                avail = snd_pcm_avail_update(handle);
                period++;
        }
}

static void async_capture_callback(snd_async_handler_t *ahandler)
{
        snd_pcm_t *handle = snd_async_handler_get_pcm(ahandler);
        snd_pcm_sframes_t avail;
        int err;
        
        avail = snd_pcm_avail_update(handle);
        while ((avail >= period_size) /*&& ((period*period_size) < (CHIRP_SIZE-100))*/ ) {  // segmentation fault checking disabled

                err = snd_pcm_readi(handle, (signal+cperiod*period_size), period_size);
                if (err < 0) {
                        printf("Read error: %s\n", snd_strerror(err));
                        exit(EXIT_FAILURE);
                }
                if (err != period_size) {
                        printf("Read error: red %i expected %li\n", err, period_size);
                        exit(EXIT_FAILURE);
                }
                avail = snd_pcm_avail_update(handle);
                cperiod++;
        }
}


int main(int argc, char *argv[])
{
        snd_pcm_t *playback_handle, *capture_handle;
        int err;
        snd_pcm_hw_params_t *hwparams;
        snd_pcm_sw_params_t *swparams;
        signed short *frame;  // pointer to array of samples
        unsigned int chn;
        snd_pcm_channel_area_t *areas;

        struct async_private_data data;
        snd_async_handler_t *chandler, *phandler;
        int count;
        unsigned int i,j,m,n;
        unsigned int delay[10]; //store delay of signifed correlation
        long int l,r;  // store correlation at strict time
        long int correlationl[SIGNAL_SAMPLES]; //array to store correlation curve
        long int correlationr[SIGNAL_SAMPLES]; //array to store correlation curve
        int L_signal[SIGNAL_SAMPLES];
        int R_signal[SIGNAL_SAMPLES];

        FILE *out;

        snd_pcm_hw_params_alloca(&hwparams);
        snd_pcm_sw_params_alloca(&swparams);

        printf("Simple PC sonar ver. 000000001 starting work.. \n");

//open and set playback device
        if ((err = snd_pcm_open(&playback_handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
                printf("Playback open error: %s\n", snd_strerror(err));
                return 0;
        }
        
        if ((err = set_hwparams(playback_handle, hwparams, 1)) < 0) {
                printf("Setting of hwparams failed: %s\n", snd_strerror(err));
                exit(EXIT_FAILURE);
        }
        if ((err = set_swparams(playback_handle, swparams)) < 0) {
                printf("Setting of swparams failed: %s\n", snd_strerror(err));
                exit(EXIT_FAILURE);
        }

//open and set capture device
        if ((err = snd_pcm_open(&capture_handle, device, SND_PCM_STREAM_CAPTURE, 0)) < 0) {
                printf("Playback open error: %s\n", snd_strerror(err));
                return 0;
        }
        
        if ((err = set_hwparams(capture_handle, hwparams, 2)) < 0) {
                printf("Setting of hwparams failed: %s\n", snd_strerror(err));
                exit(EXIT_FAILURE);
        }
        if ((err = set_swparams(capture_handle, swparams)) < 0) {
                printf("Setting of swparams failed: %s\n", snd_strerror(err));
                exit(EXIT_FAILURE);
        }

// generate ping pattern

        chirp_size=linear_windowed_chirp(chirp,1000000, CHIRP_OFFSET);

// register playback callback 
        err = snd_async_add_pcm_handler(&phandler, playback_handle, async_playback_callback, &data); // fill by dummy &data
        if (err < 0) {
                printf("Unable to register async handler\n");
                exit(EXIT_FAILURE);
        }

        if ((err = snd_pcm_prepare (playback_handle)) < 0) {
                fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
                         snd_strerror (err));
                exit (1);
        }

/*      for (period = 0; period < 2; period++) {

                err = snd_pcm_writei(playback_handle, (chirp+period*period_size), period_size);
                if (err < 0) {
                        printf("Initial write error: %s\n", snd_strerror(err));
                        exit(EXIT_FAILURE);
                }
                if (err != period_size) {
                        printf("Initial write error: written %i expected %li\n", err, period_size);
                        exit(EXIT_FAILURE);
                }
        }*/

// register capture callback 
        err = snd_async_add_pcm_handler(&chandler, capture_handle, async_capture_callback, &data); // fill by dummy &data
        if (err < 0) {
                printf("Unable to register async handler\n");
                exit(EXIT_FAILURE);
        }

        snd_pcm_link(capture_handle,playback_handle); //link capture and playback together

//start sream
        if ((err = snd_pcm_prepare (capture_handle)) < 0) {
                fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
                         snd_strerror (err));
                exit (1);
        }

        err = snd_pcm_start(capture_handle);
        if (err < 0) {
                        printf("Start error: %s\n", snd_strerror(err));
                        exit(EXIT_FAILURE);
        }
        
//wait until all samples aren't transmitted
        printf("Waiting for transmitt all samples\n");
        while(cperiod<10) {
                sleep(1);
                printf(".");
        }       

////   stop audio??


        j=0;
        for(i=0;i < SIGNAL_SAMPLES;i++){
          L_signal[i]=signal[j];
          R_signal[i]=signal[j+1];
          j+=2;
        }

//        linear_windowed_chirp(L_signal,1000000, 1000);

        printf("\nData transmitted... \ncorrelating...\n");
        for(n=0; n < (SIGNAL_SAMPLES - chirp_size);n++){
          l=0;
          r=0;
          for(m=CHIRP_OFFSET;m < chirp_size;m++)
          {
            l += chirp[m]*L_signal[m+n];        // correlate with left channel
            r += chirp[m]*R_signal[m+n];        // correlate with right channel
          }
          correlationl[n]=l;
          correlationr[n]=r;
        }

        printf("\nSearching echos...\n");
        r=0;
        l=0;
        for(n=0; n < (SIGNAL_SAMPLES - chirp_size);n++){                        //najde nejvetsi korelace
          if (l < correlationl[n]){
          delay[1] = n;
          l = correlationl[n];
          }
          if (r < correlationr[n]){
          delay[2] = n;
          r = correlationr[n];
          }
        }

  out=fopen("/tmp/sonar.txt","w");
  j=0;
  for(i=0;i<=100000;i++){
    fprintf(out,"%6d %6d %6d %6d %9ld %9ld\n",i,chirp[i],L_signal[i],R_signal[i],correlationl[i], correlationr[i]);
    j+=2;
  }
  fclose(out);

        printf("\nEcho zacina na: %d vzorku.\n", delay[1]);
        printf("Casove na: %f s\n", ((float)delay[1]/rate));
        printf("vzdalenost: %f m\n", (SOUND_SPEED*(float)delay[1]/rate));

        snd_pcm_close(playback_handle);
        snd_pcm_close(capture_handle); 
        return 0;
}