USB serial port input into Bela?

Yes you should be able to use it and receive it in the Bela program.

Any generic tutorial for reading a serial port on Linux in C or C++ should do.
Make sure you read / write your serial port from a separate thread from the audio thread.
A thread on Bela is called AuxiliaryTask, which is a wrapper for Xenomai thread. A number of examples show how to use AuxiliaryTask, for instance:

06-Sensors/capacitive-touch/
11-Extras/bucket-brigade-chorus/
04-Audio/FFT-phase-vocoder/

The first also show how traditional Linux programming techniques (in this case communication over I2C) can be used seamlessly on Bela.

Out of curiosity, what do you need the Arduino for? Is there something specific that runs on it that you would not be able to run on Bela ?

I see, dr Ybot.

Hey dr-offig,

did you manage to get this going?
I'm also trying to set up a serial connection between an Arduino nano (inside an expression pedal ) and a pd-patch (with libpd).

I hacked together a test .c - file to see if it works at all on the beaglebone, and it does when I run it via ssh.
Sourced together from these tutorials:
https://github.com/xanthium-enterprises/Serial-Port-Programming-on-Linux/blob/master/USB2SERIAL_Read/Reciever%20(PC%20Side)/SerialPort_read.c
and
https://forum.arduino.cc/index.php?topic=288234.0

I posted the resulting SerialPort_read.c here: https://gist.github.com/anonymous/e356e39f783226e0656a2c6cee0c1e75
Compile it with gcc -o SerialPort_read SerialPort_read.c , run it with SerialPort_read.c , and it should post whatever comes from an Arduino Serial at 9600bd (if that is connected to your device as /dev/ttyUSB0 ).
But when I try to squeeze these into the render.cpp - file alongside the pd-patch, it won't get the Serial connection going (although it compiles):
https://gist.github.com/anonymous/61262807963dbbced9e02ce6c1aa8813

And then there's the question of how to get the resulting message back into PD (if i manage to make it connect..).
Where should the parsing part go??

Anyway, curious if you found a solution
Best,
Jan

janklug But when I try to squeeze these into the render.cpp - file alongside the pd-patch, it won't get the Serial connection going (although it compiles):
https://gist.github.com/anonymous/61262807963dbbced9e02ce6c1aa8813

Not sure how that code can compile: you have lots of function calls at the top that are not within a function, so it surely does not compile.

Maybe for some bug (e.g.: this ) the IDE does not try to recompile your project? can you clean the project (project settings tab -> manage projects -> clean) and try hitting the run button again?

ah, sorry - a very simple (but quite embarrassing) solution to that mystery: posted the wrong version...

this is compiling for me, but throwing "Error! in Opening ttyUSB0":
https://gist.github.com/anonymous/149850dc06a309caeb1872b4431493ab

indeed, it was the wrong device.. it opens with ttyUSB0
thanks for checking!

So the next step is to squeeze in the checking-for-incoming-serial-data, parsing that and sending it to the pd-patch.

would that go into the render function?
Anyway, time to take a break; better to look at that tomorrow

You would need a separate thread to monitor the serial port. You could then set a global variable from it. Then from the audio thread (e.g.: inside render) you would read the content of the global variable and send a message to a receiver in Pd, using a syntax like this:

	libpd_float("yourReceiver", state);

this would send to a [r yourReceiver] object in libpd.
In order to do this you'd need a Pd project with a custom render.cpp file. See the example 08-PureData/customRender.

On the other hand, the [serial] object is supported by libpd(though I have not tested it), so you may skip all you've done so far and simply try running your Pd patch with the [serial] object in it.

On the other hand again, I would ask you: why do you need Arduino for this application? Is there no way you could connect your device straight into Bela?

thanks!

the libpd-approach seems to make more sense then.
can't find the [serial] object though. Could it be [comport]?
I managed to install that on my mac, but can't figure out how to do that with bela...

but i can try to be patient and wait for the step-by-step guide

The reason why I attempt it via the Arduino is composed of these parts:
- I'd like to use the same pedal (and other components) in multiple setups, depending on context; also with Max on my laptop, which works nicely plug-and-play via USB connection.
- I'd like to learn how to do that
- experimenting with other sensors that I know how to handle in arduino, incl. pre-cooking the data
- making it easier to experiment for students who have Arduino experience

ok,that sounds like the best approach then!

is there anything else necessary to get the connection to pd working than

1) #include <libpd/z_libpd.h> , #include <libpd/s_stuff.h>
2) libpd_float("arduino", 440); // in render()
3) a receive object in pd called 'arduino'
?
Can't get it to work... Do I need to register anything?

your receiver object should be

 [r arduino] 

Check out this section of the libpd wiki

And the render.cpp file should live in the same folder as your project ( to make sure it is getting compiled and linked in, try to add a printf statement in setup() and make sure it shows up on the console).

yes, the render.cpp, serial receiving and parsing works fine, but the [r arduino] (which for testing is hooked to a osc~) doesn't seem to receive anything..

https://gist.github.com/anonymous/8be73ad30bb20abe4938cfccb0bb1b3b

ok, I indeed indeed misunderstood that documentation a bit.

however: got it to work now with a modified default_libpd_render.cpp.
https://gist.github.com/anonymous/7ebced1ad2d194961aacc7bd5f9eab1f

thanks a lot

dr-offig looks nice, by the way, what wold be the next step? I mean, would you have a sample render.cpp file which makes actual use of the Serial port, sending and receiving formatted data?