From 9552f73fbd0559a314fc6f8f442e3e90a7d5d4d4 Mon Sep 17 00:00:00 2001
From: Harvie <tomas@mudrunka.cz>
Date: Mon, 1 Nov 2010 04:11:37 +0100
Subject: [PATCH 1/1] Added beatdetect - experimental software to detect knocks
 using alsa

---
 c/ghetto-sound-system/beatdetect.c | 89 ++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 c/ghetto-sound-system/beatdetect.c

diff --git a/c/ghetto-sound-system/beatdetect.c b/c/ghetto-sound-system/beatdetect.c
new file mode 100644
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);
+	}
-- 
2.30.2