Тут показані розбіжності між вибраною ревізією та поточною версією сторінки.
Наступна ревізія | Попередня ревізія | ||
soundcard_oscilloscope [2013/08/16 18:04] wombat створено |
soundcard_oscilloscope [2015/10/01 01:05] (поточний) wombat [Существующие программы] |
||
---|---|---|---|
Рядок 1: | Рядок 1: | ||
+ | ====== Осциллограф из звуковой платы ====== | ||
+ | ====== Схема ====== | ||
+ | |||
+ | {{::soundcard_oscilloscope_probe-1.jpg?300|}} | ||
+ | |||
+ | |||
+ | |||
+ | ====== Существующие программы ====== | ||
+ | |||
+ | [[http://xoscope.sourceforge.net/ | xoscope]] | ||
+ | |||
+ | [[https://github.com/xobs/osqoop | Osqoop]] использует доступ к звуковой плате через драйвер OSS, поэтому на современных системах нуждается в [[http://alsa.opensrc.org/Aoss | его эмуляции]]. | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
+ | ====== Своя программа ====== | ||
+ | |||
+ | [[http://www.linuxjournal.com/article/6735?page=0,2 | | ||
+ | Introduction to Sound Programming with ALSA]] | ||
+ | |||
+ | [[http://users.suse.com/~mana/alsa090_howto.html#sect03 | ALSA Programming HOWTO: PCM capture]] | ||
+ | |||
+ | [[http://equalarea.com/paul/alsa-audio.html | A Tutorial on Using the ALSA Audio API]] | ||
+ | |||
+ | [[http://www.alsa-project.org/main/index.php/Main_Page | Advanced Linux Sound Architecture (ALSA) project homepage]] | ||
+ | |||
+ | ===== Пробная программа ===== | ||
+ | |||
+ | <file c "soundcard_oscilloscope.c"> | ||
+ | /* | ||
+ | soundcard_oscilloscope.c | ||
+ | |||
+ | v.0.1 | ||
+ | |||
+ | 17.08.2013 Vladimir Smolyar | ||
+ | |||
+ | GPLv3 | ||
+ | |||
+ | */ | ||
+ | |||
+ | |||
+ | |||
+ | #include <stdio.h> | ||
+ | #include <stdlib.h> | ||
+ | #include <alsa/asoundlib.h> | ||
+ | #include <math.h> | ||
+ | | ||
+ | main (int argc, char *argv[]) | ||
+ | { | ||
+ | int i,j; | ||
+ | int err; | ||
+ | int buf[128]; | ||
+ | snd_pcm_t *capture_handle; | ||
+ | snd_pcm_hw_params_t *hw_params; | ||
+ | unsigned int val,val2; | ||
+ | int dir; | ||
+ | int peak_value, average; | ||
+ | size_t size; | ||
+ | int number; | ||
+ | |||
+ | err = snd_pcm_open (&capture_handle, argv[1], SND_PCM_STREAM_CAPTURE, 0); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf (stderr, "cannot open audio device %s (%s)\n", | ||
+ | argv[1], | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Audio device opened.\n"); | ||
+ | |||
+ | err = snd_pcm_hw_params_malloc (&hw_params); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf(stderr, "cannot allocate hardware parameter structure (%s)\n", | ||
+ | snd_strerror(err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Hardware parameter structure allocated.\n"); | ||
+ | |||
+ | err = snd_pcm_hw_params_any(capture_handle, hw_params); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf(stderr, "cannot initialize hardware parameter structure (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Hardware parameter structure initialized.\n"); | ||
+ | | ||
+ | |||
+ | err = snd_pcm_hw_params_set_access (capture_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf (stderr, "cannot set access type (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Access type set.\n"); | ||
+ | |||
+ | |||
+ | err = snd_pcm_hw_params_set_format (capture_handle, hw_params, SND_PCM_FORMAT_S16_LE); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf (stderr, "cannot set sample format (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Sample format set.\n"); | ||
+ | |||
+ | val = 44100; | ||
+ | err = snd_pcm_hw_params_set_rate_near (capture_handle, hw_params, &val, &dir); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf (stderr, "cannot set sample rate (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Sample rate set.\n"); | ||
+ | |||
+ | err = snd_pcm_hw_params_set_channels (capture_handle, hw_params, 1); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf (stderr, "cannot set channel count (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Channel count set.\n"); | ||
+ | | ||
+ | |||
+ | err = snd_pcm_hw_params (capture_handle, hw_params); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf(stderr, "cannot set parameters (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Parameters set.\n"); | ||
+ | |||
+ | snd_pcm_hw_params_free (hw_params); | ||
+ | err = snd_pcm_prepare (capture_handle); | ||
+ | if (err < 0) | ||
+ | { | ||
+ | fprintf (stderr, "cannot prepare audio interface for use (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | else printf("Audio interface prepared for use.\n"); | ||
+ | |||
+ | //for (i = 0; i < 10; ++i) | ||
+ | peak_value = 0; | ||
+ | average = 0; | ||
+ | while (1) | ||
+ | { | ||
+ | err = snd_pcm_readi (capture_handle, buf, 128); | ||
+ | if (err != 128) | ||
+ | { | ||
+ | fprintf (stderr, "read from audio interface failed (%s)\n", | ||
+ | snd_strerror (err)); | ||
+ | exit (1); | ||
+ | } | ||
+ | |||
+ | else | ||
+ | { | ||
+ | //printf("%d\n",abs(buf[0])); | ||
+ | //printf("%d\n",abs(peak_value)); | ||
+ | //printf(".\n"); | ||
+ | |||
+ | for (i=0; i<128; i++) | ||
+ | { | ||
+ | average += (abs(buf[i]) - average)/512; | ||
+ | if (abs(buf[i]) > abs(peak_value)) | ||
+ | { | ||
+ | peak_value = buf[i]; | ||
+ | //printf("Peak: %d\n",peak_value); | ||
+ | //write(1, *peak_value, sizeof(peak_value)); | ||
+ | |||
+ | } | ||
+ | } | ||
+ | printf("|"); | ||
+ | number = round(100 * ((float) average) / 2147483648); | ||
+ | for (j=0; j < number; j++) printf("="); | ||
+ | printf(">"); | ||
+ | for (j=number; j < 70; j++) printf("-"); | ||
+ | //printf("average: %d\n",average); | ||
+ | printf("|\n"); | ||
+ | } | ||
+ | } | ||
+ | snd_pcm_close (capture_handle); | ||
+ | exit (0); | ||
+ | } | ||
+ | </file> | ||
+ | |||
+ | |||
+ | ====== Статьи ====== | ||
+ | |||
+ | [[http://www.energeticforum.com/renewable-energy/3901-el-cheapo-oscilloscope-using-pc-soundcard.html | El-Cheapo Oscilloscope using PC + soundcard]] | ||
+ | |||
+ | [[http://www.instructables.com/id/Use-Your-Laptop-as-Oscilloscope/?ALLSTEPS | Use Your Laptop as Oscilloscope]] | ||
+ | |||
+ | [[http://www.opencircuits.com/Oscilloscope]] |