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///////////////////////////////////////////////////////////////////////////////////
// This small demo of sonar.
// Program allow distance measuring.
//
//
///////////////////////////////////////////////////////////////////////////////////
#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 verbose = 0; /* verbose flag */
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
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;
static const float fmax = 10000;
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);
/* struct async_private_data *data = snd_async_handler_get_callback_private(ahandler);
signed short *samples = data->samples;
snd_pcm_channel_area_t *areas = data->areas;*/
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);
/* struct async_private_data *data = snd_async_handler_get_callback_private(ahandler);
signed short *samples = data->samples;
snd_pcm_channel_area_t *areas = data->areas;*/
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
double l,r; // store correlation at strict time
long int correlationl[100000]; //array to store correlation curve
long int correlationr[100000]; //array to store correlation curve
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, 200);
/// 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);
}
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);
}
//start capture
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);
}
//start playback
if (snd_pcm_state(playback_handle) == SND_PCM_STATE_PREPARED) {
err = snd_pcm_start(playback_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(".");
}
printf("\nData transmitted... \ncorrelating...\n");
i=0;
for(n=0; n < (SIGNAL_SAMPLES - chirp_size);n++){ //we have interleaved data we must have 2 saples step
l=0;
r=0;
j=0;
for(m=0;m < chirp_size;m++)
{
l += chirp[m]*signal[i+j]; // correlate with left channel
r += chirp[m]*signal[i+j+1]; // correlate with right channel
j+=2;
}
correlationl[n]=l;
correlationr[n]=r;
i+=2;
}
/* printf("\nFinding 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[1] = n;
r = correlationr[n];
}
}*/
out=fopen("./output.txt","w");
j=0;
for(i=0;i<=100000;i++){
fprintf(out,"%6d %6d %6d %6d %9ld %9ld\n",i,chirp[i],signal[j],signal[j+1],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;
}