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/* fmscan.c - v4l radio band scanner using signal strength
Copyright (C) 2004, 2006, 2009 Ben Pfaff <blp@cs.stanford.edu>
Copyright (C) 1999 Russell Kroll <rkroll@exploits.org>
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <math.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include "fmlib.h"
#define TRIES 25 /* get 25 samples */
#define LOCKTIME 400000 /* wait 400ms for card to lock on */
#define SAMPLEDELAY 15000 /* wait 15ms between samples */
static void
usage(void)
{
printf("fmtools fmscan version %s\n\n", VERSION);
printf("usage: %s [-h] [-d <dev>] [-T <tuner>] [-s <freq>] [-e <freq>] [-i <freq>] [-t <%%>]\n\n", program_name);
printf("Auxiliary program to scan a frequency band for radio stations.\n\n");
printf(" -h - display this help\n");
printf(" -d <dev> - select device (default: /dev/radio0)\n");
printf(" -T <tuner> - select tuner (default: 0)\n");
printf(" -s <freq> - set start of scanning range to <freq>\n");
printf(" -e <freq> - set end of scanning range to <freq>\n");
printf(" -i <freq> - set increment value between channels to <freq>\n");
printf(" -t <%%> - set signal strength percentage to lock onto <%%>\n");
printf(" <freq> - a value in the format nnn.nn (MHz)\n");
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
struct tuner tuner;
int tries = TRIES;
double perc, begval, incval, endval, threshold, mhz;
const char *device = NULL;
bool override = false;
bool quiet = false;
int index = 0;
int i;
program_name = argv[0];
/* USA defaults */
begval = 87.9; /* start at 87.9 MHz */
incval = 0.20; /* increment 0.2 MHz */
endval = 107.9; /* stop at 107.9 MHz */
threshold = 0.5; /* 50% signal strength */
for (;;) {
int option = getopt(argc, argv, "+e:hi:s:od:T:t:q");
if (option == -1)
break;
switch (option) {
case 'd':
device = optarg;
break;
case 'T':
index = atoi(optarg);
break;
case 'e':
endval = atof(optarg);
break;
case 'i':
incval = atof(optarg);
break;
case 's':
begval = atof(optarg);
break;
case 'o':
override = true;
break;
case 't':
threshold = atof(optarg)/100.;
break;
case 'q':
quiet = true;
break;
case 'h':
default:
usage();
break;
}
}
tuner_open(&tuner, device, index);
if (!override) {
double min = tuner_get_min_freq(&tuner) / 16000.0;
double max = tuner_get_max_freq(&tuner) / 16000.0;
if (begval < min) {
begval = min;
printf("Setting start to tuner minimum %.2f MHz\n",
begval);
}
if (endval > max) {
endval = max;
printf("Setting end to tuner maximum %.2f MHz\n",
endval);
}
}
printf("Scanning range: %2.2f - %2.2f MHz (%2.2f MHz increments)...\n",
begval, endval, incval);
for (i = 0; (mhz = begval + i * incval) <= endval; i++) {
long long int freq;
long int totsig;
int i;
freq = mhz * 16000 + 0.5;
if (!override) {
if (freq < tuner_get_min_freq(&tuner))
freq = tuner_get_min_freq(&tuner);
else if (freq > tuner_get_max_freq(&tuner))
freq = tuner_get_max_freq(&tuner);
}
tuner_set_freq(&tuner, freq, override);
if (!quiet) {
printf("%2.2f:\r", mhz);
fflush(stdout);
}
tuner_usleep(&tuner, LOCKTIME);
totsig = 0;
for (i = 0; i < tries; i++) {
totsig += tuner_get_signal(&tuner);
perc = totsig / (65535.0 * (i + 1));
if (!quiet) {
printf("%2.2f: checking: %3.1f%% (%d/%d)"
" \r",
mhz, perc * 100.0, i + 1, tries);
fflush(stdout);
}
tuner_usleep(&tuner, SAMPLEDELAY);
}
/* clean up the display */
if (!quiet)
printf(" \r");
perc = totsig / (65535.0 * tries);
if (perc > threshold)
printf("%2.2f: %3.1f%%\n",
mhz, perc * 100.0);
}
tuner_close(&tuner);
return 0;
}
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