Using Arduino with Bela + Pure Data

giuliomoro

Knallberto Is there (a) a way to automatically mute the speaker when headphones are connected and/or (b) a way to control headphone and speaker volume seperately from PD?

Doing it automatically is not possible unless you use a jack with a switching contact. The speaker is connected to the line output, so you can adjust the line output and headphones level separately. This is normally done via the command line options, but it can be set at runtime by calling Bela_setLineOutLevel(). You'll need a custom C++ wrapper for PureData.

Create a .cpp file in your Pd project and paste this content into it (it requires that you are running the latest dev branch):

#include <Bela.h>
#include <libraries/BelaLibpd/BelaLibpd.h>

int Bela_floatHook(const char *source, float value)
{
        if(strncmp(source, "bela_setLineOutLevel", prefixLength) == 0)
        {
                Bela_setLineOutLevel(-1, value); // -1 means: apply to all channels
                return 0;
        }
        return 1;
}

void Bela_userSettings(BelaInitSettings *settings)
{
        settings->uniformSampleRate = 1;
        settings->interleave = 0;
        settings->analogOutputsPersist = 0;
        settings->floatHook = Bela_floatHook;
}

bool setup(BelaContext *context, void *userData)
{
        bool success = BelaLibpd_setup(context, userData, {});
        if(!success)
                return false;
        libpd_bind("bela_setLineOutLevel");
        return true;
}

void render(BelaContext *context, void *userData)
{
        BelaLibpd_render(context, userData);
}

void cleanup(BelaContext *context, void *userData)
{
        BelaLibpd_cleanup(context, userData);
}

Then in Pd you should be able to send a float to

[send Bela_setLineOutLevel]

to adjust the speaker level. You can expand the above to control headphone output (calling the function Bela_setHpLevel(int channel, float decibels)).

Knallberto

Thanks for the answer and the code.

This means for controlling Headphone level the code should look like this?

#include <Bela.h>
#include <libraries/BelaLibpd/BelaLibpd.h>

int Bela_floatHook(const char *source, float value)
{        //lineout
        if(strncmp(source, "bela_setLineOutLevel", prefixLength) == 0)
        {
                Bela_setLineOutLevel(-1, value); // -1 means: apply to all channels
                return 0;
        }
        //headphones
        if(strncmp(source, "bela_setHpLevel", prefixLength) == 0)
    {
        Bela_setHpLevel(-1, value); 
        return 0;
    }
    return 1; 
}

void Bela_userSettings(BelaInitSettings *settings)
{
        settings->uniformSampleRate = 1;
        settings->interleave = 0;
        settings->analogOutputsPersist = 0;
        settings->floatHook = Bela_floatHook;
}

bool setup(BelaContext *context, void *userData)
{
        bool success = BelaLibpd_setup(context, userData, {});
        if(!success)
                return false;
        libpd_bind("bela_setLineOutLevel");
        return true;
}

void render(BelaContext *context, void *userData)
{
        BelaLibpd_render(context, userData);
}

void cleanup(BelaContext *context, void *userData)
{
        BelaLibpd_cleanup(context, userData);
}

And then I can send float to
[send Bela_setLineOutLevel]
and
[send Bela_setHpLevel] ?

What range is the float supposed to be?

giuliomoro

you need

        libpd_bind("bela_setHpOutLevel");

in setup, after the other one.

The value is in decibels. Something like -100 should work..

Knallberto

Like this?

bool setup(BelaContext *context, void *userData) { bool success = BelaLibpd_setup(context, userData, {}); if(!success) return false; libpd_bind("bela_setLineOutLevel"); libpd_bind("bela_setHpOutLevel"); return true; }

giuliomoro

yes

Knallberto

Now I get:
use of undeclared identifier 'prefixLength' column: 52, line: 6 use of undeclared identifier 'prefixLength' column: 47, line: 12 no member named 'floatHook' in 'BelaInitSettings' column: 19, line: 25

with this cpp:
`
#include <Bela.h>
#include <libraries/BelaLibpd/BelaLibpd.h>

int Bela_floatHook(const char *source, float value)
{ //lineout
if(strncmp(source, "bela_setLineOutLevel", prefixLength) == 0)
{
Bela_setLineOutLevel(-1, value); // -1 means: apply to all channels
return 0;
}
//headphones
if(strncmp(source, "bela_setHpLevel", prefixLength) == 0)
{
Bela_setHpLevel(-1, value);
return 0;
}
return 1;
}

void Bela_userSettings(BelaInitSettings *settings)
{
settings->uniformSampleRate = 1;
settings->interleave = 0;
settings->analogOutputsPersist = 0;
settings->floatHook = Bela_floatHook;
}

bool setup(BelaContext *context, void *userData)
{
bool success = BelaLibpd_setup(context, userData, {});
if(!success)
return false;
libpd_bind("bela_setLineOutLevel");
libpd_bind("bela_setHpOutLevel");
return true;
}

void render(BelaContext *context, void *userData)
{
BelaLibpd_render(context, userData);
}

void cleanup(BelaContext *context, void *userData)
{
BelaLibpd_cleanup(context, userData);
}
`

Regarding the pixelbone branch I will start a new discussion.

giuliomoro

right , sorry I should have tried it myself. This should work. At least it builds:

#include <Bela.h>
#include <string.h>
#include <libraries/BelaLibpd/BelaLibpd.h>

int floatHook(const char *source, float value)
{
	if(strcmp(source, "bela_setLineOutLevel") == 0)
	{
		Bela_setLineOutLevel(-1, value); // -1 means: apply to all channels
		return 0;
	}
	if(strcmp(source, "bela_setHpLevel") == 0)
	{
		Bela_setHpLevel(-1, value); // -1 means: apply to all channels
		return 0;
	}
	return 1;
}

void Bela_userSettings(BelaInitSettings *settings)
{
	settings->uniformSampleRate = 1;
	settings->interleave = 0;
	settings->analogOutputsPersist = 0;
}

bool setup(BelaContext *context, void *userData)
{
	BelaLibpdSettings settings {};
	settings.floatHook = floatHook;

	bool success = BelaLibpd_setup(context, userData, {});
	if(!success)
		return false;
	libpd_bind("bela_setLineOutLevel");
	libpd_bind("bela_setHpLevel");
	return true;
}

void render(BelaContext *context, void *userData)
{
	BelaLibpd_render(context, userData);
}

void cleanup(BelaContext *context, void *userData)
{
	BelaLibpd_cleanup(context, userData);
}

Knallberto

Thanks. This code compiles. The values come in correct, but the HP volume does not change. I get values to Pure Data in a range from -100 to 0. I try to send them with s Bela_setHPLevel.

giuliomoro

it should be bela_setHpLevel , not bela_setHPLevel .

Knallberto

so like this?

Still headphone volume stays the same.

giuliomoro

ok this one is tested and it works:

#include <Bela.h>
#include <string.h>
#include <libraries/BelaLibpd/BelaLibpd.h>

int floatHook(const char *source, float value)
{
	if(strcmp(source, "bela_setLineOutLevel") == 0)
	{
		Bela_setLineOutLevel(-1, value); // -1 means: apply to all channels
		return 0;
	}
	if(strcmp(source, "bela_setHpLevel") == 0)
	{
		Bela_setHpLevel(-1, value); // -1 means: apply to all channels
		return 0;
	}
	return 1;
}

void Bela_userSettings(BelaInitSettings *settings)
{
	settings->uniformSampleRate = 1;
	settings->interleave = 0;
	settings->analogOutputsPersist = 0;
}

bool setup(BelaContext *context, void *userData)
{
	BelaLibpdSettings settings {};
	settings.floatHook = floatHook;
	settings.bindSymbols = {
		"bela_setLineOutLevel",
		"bela_setHpLevel"
	};
	return BelaLibpd_setup(context, userData, settings);
}

void render(BelaContext *context, void *userData)
{
	BelaLibpd_render(context, userData);
}

void cleanup(BelaContext *context, void *userData)
{
	BelaLibpd_cleanup(context, userData);
}

Knallberto

Perfect, thank you so much!