fmscan.c

   1 /* fmscan.c - v4l radio band scanner using signal strength
   2
   3    Copyright (C) 2004, 2006, 2009 Ben Pfaff <blp@cs.stanford.edu>
   4    Copyright (C) 1999 Russell Kroll <rkroll@exploits.org>
   5
   6    This program is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the Free
   8    Software Foundation; either version 2 of the License, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14    more details.
  15
  16    You should have received a copy of the GNU General Public License along with
  17    this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include <math.h>
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <fcntl.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <sys/ioctl.h>
  28
  29 #include "fmlib.h"
  30
  31 #define TRIES           25              /* get 25 samples                 */
  32 #define LOCKTIME        400000          /* wait 400ms for card to lock on */
  33 #define SAMPLEDELAY     15000           /* wait 15ms between samples      */
  34
  35 static void
  36 usage(void)
  37 {
  38         printf("fmtools fmscan version %s\n\n", VERSION);
  39         printf("usage: %s [-h] [-d <dev>] [-T <tuner>] [-s <freq>] [-e <freq>] [-i <freq>] [-t <%%>]\n\n", program_name);
  40
  41         printf("Auxiliary program to scan a frequency band for radio stations.\n\n");
  42
  43         printf("  -h        - display this help\n");
  44         printf("  -d <dev>  - select device (default: /dev/radio0)\n");
  45         printf("  -T <tuner> - select tuner (default: 0)\n");
  46         printf("  -s <freq> - set start of scanning range to <freq>\n");
  47         printf("  -e <freq> - set end of scanning range to <freq>\n");
  48         printf("  -i <freq> - set increment value between channels to <freq>\n");
  49         printf("  -t <%%>    - set signal strength percentage to lock onto <%%>\n");
  50         printf("  <freq>    - a value in the format nnn.nn (MHz)\n");
  51
  52         exit(EXIT_SUCCESS);
  53 }
  54
  55 int main(int argc, char **argv)
  56 {
  57         struct tuner tuner;
  58         int tries = TRIES;
  59         double perc, begval, incval, endval, threshold, mhz;
  60         const char *device = NULL;
  61         bool override = false;
  62         bool quiet = false;
  63         int index = 0;
  64         int i;
  65
  66         program_name = argv[0];
  67
  68         /* USA defaults */
  69         begval = 87.9;          /* start at 87.9 MHz */
  70         incval = 0.20;          /* increment 0.2 MHz */
  71         endval = 107.9;         /* stop at 107.9 MHz */
  72         threshold = 0.5;        /* 50% signal strength */
  73
  74         for (;;) {
  75                 int option = getopt(argc, argv, "+e:hi:s:od:T:t:q");
  76                 if (option == -1)
  77                         break;
  78
  79                 switch (option) {
  80                 case 'd':
  81                         device = optarg;
  82                         break;
  83                 case 'T':
  84                         index = atoi(optarg);
  85                         break;
  86                 case 'e':
  87                         endval = atof(optarg);
  88                         break;
  89                 case 'i':
  90                         incval = atof(optarg);
  91                         break;
  92                 case 's':
  93                         begval = atof(optarg);
  94                         break;
  95                 case 'o':
  96                         override = true;
  97                         break;
  98                 case 't':
  99                         threshold = atof(optarg)/100.;
 100                         break;
 101                 case 'q':
 102                         quiet = true;
 103                         break;
 104                 case 'h':
 105                 default:
 106                         usage();
 107                         break;
 108                 }
 109         }
 110
 111         tuner_open(&tuner, device, index);
 112
 113         if (!override) {
 114                 double min = tuner_get_min_freq(&tuner) / 16000.0;
 115                 double max = tuner_get_max_freq(&tuner) / 16000.0;
 116                 if (begval < min) {
 117                         begval = min;
 118                         printf("Setting start to tuner minimum %.1f MHz\n",
 119                                begval);
 120                 }
 121                 if (endval > max) {
 122                         endval = max;
 123                         printf("Setting end to tuner maximum %.1f MHz\n",
 124                                endval);
 125                 }
 126         }
 127
 128         printf("Scanning range: %2.1f - %2.1f MHz (%2.1f MHz increments)...\n",
 129                begval, endval, incval);
 130
 131         for (i = 0; (mhz = begval + i * incval) <= endval; i++) {
 132                 long long int freq;
 133                 long int totsig;
 134                 int i;
 135
 136                 freq = mhz * 16000 + 0.5;
 137                 if (!override) {
 138                         if (freq < tuner_get_min_freq(&tuner))
 139                                 freq = tuner_get_min_freq(&tuner);
 140                         else if (freq > tuner_get_max_freq(&tuner))
 141                                 freq = tuner_get_max_freq(&tuner);
 142                 }
 143                 tuner_set_freq(&tuner, freq, override);
 144
 145                 if (!quiet) {
 146                         printf("%2.1f:\r", mhz);
 147                         fflush(stdout);
 148                 }
 149                 tuner_usleep(&tuner, LOCKTIME);
 150
 151                 totsig = 0;
 152                 for (i = 0; i < tries; i++) {
 153                         totsig += tuner_get_signal(&tuner);
 154                         perc = totsig / (65535.0 * i);
 155                         if (!quiet) {
 156                                 printf("%2.1f: checking: %3.1f%% (%d/%d)"
 157                                        "    \r",
 158                                        mhz, perc * 100.0, i + 1, tries);
 159                                 fflush(stdout);
 160                         }
 161                         tuner_usleep(&tuner, SAMPLEDELAY);
 162                 }
 163
 164                 /* clean up the display */
 165                 if (!quiet)
 166                         printf("                                          \r");
 167
 168                 perc = totsig / (65535.0 * tries);
 169
 170                 if (perc > threshold)
 171                         printf("%2.1f: %3.1f%%\n",
 172                                mhz, perc * 100.0);
 173         }
 174
 175         tuner_close(&tuner);
 176         return 0;
 177 }