Added beatdetect - experimental software to detect knocks using alsa

diff --git a/c/ghetto-sound-system/beatdetect.c b/c/ghetto-sound-system/beatdetect.c
new file mode 100644 (file)
index 0000000..b520ae8
--- /dev/null
+++ b/c/ghetto-sound-system/beatdetect.c
@@ -0,0 +1,89 @@
+//CFLAGS=-lasound make beatdetect; echo -----; ./beatdetect hw:default
+       #include <stdio.h>
+       #include <stdlib.h>
+       #include <alsa/asoundlib.h>
+             
+       main (int argc, char *argv[])
+       {
+               int i;
+               int err;
+               short buf[128];
+               snd_pcm_t *capture_handle;
+               snd_pcm_hw_params_t *hw_params;
+       
+               if ((err = snd_pcm_open (&capture_handle, argv[1], SND_PCM_STREAM_CAPTURE, 0)) < 0) {
+                       fprintf (stderr, "cannot open audio device %s (%s)\n", 
+                                argv[1],
+                                snd_strerror (err));
+                       exit (1);
+               }
+               if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
+                       fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+                                
+               if ((err = snd_pcm_hw_params_any (capture_handle, hw_params)) < 0) {
+                       fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+       
+               if ((err = snd_pcm_hw_params_set_access (capture_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
+                       fprintf (stderr, "cannot set access type (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+       
+               if ((err = snd_pcm_hw_params_set_format (capture_handle, hw_params, SND_PCM_FORMAT_S16_LE)) < 0) { //SND_PCM_FORMAT_S16_LE
+                       fprintf (stderr, "cannot set sample format (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+       
+/*                        puts("lolopre");
+               if ((err = snd_pcm_hw_params_set_rate_near (capture_handle, hw_params, 44100, 0)) < 0) {
+                          puts("loloerr");
+                       fprintf (stderr, "cannot set sample rate (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+       
+               if ((err = snd_pcm_hw_params_set_channels (capture_handle, hw_params, 2)) < 0) {
+                       fprintf (stderr, "cannot set channel count (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+*/
+       
+               if ((err = snd_pcm_hw_params (capture_handle, hw_params)) < 0) {
+                       fprintf (stderr, "cannot set parameters (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+       
+               snd_pcm_hw_params_free (hw_params);
+       
+               if ((err = snd_pcm_prepare (capture_handle)) < 0) {
+                       fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
+                                snd_strerror (err));
+                       exit (1);
+               }
+
+               //for (i = 0; i < 10; ++i) {
+               for (i = 0; 1; ++i) {
+                       if ((err = snd_pcm_readi (capture_handle, buf, 128)) != 128) {
+                               fprintf (stderr, "read from audio interface failed (%s)\n", snd_strerror (err));
+                               exit (1);
+                       } else {
+                               int j;
+                               for(j=0;j<128;j++) if((int)buf[j] > 1000) {
+                                       printf("BOOM! %d\n", (int)buf[j]);
+                                       break;
+                               }
+                       }
+               }
+       
+               snd_pcm_close (capture_handle);
+               exit (0);
+       }