Compiling Puredata patches on Bela¶

Here's a quick guide to compiling Pd patches on Bela. Currently this only works on OSX and Linux, but Windows support will be coming soon.

You can also access the slides from the latest Bela workshop on compiling Pd patches at the following link: https://goo.gl/59hShW This also includes some handy tips for handling Bela's sensor inputs using Puredata.

Getting everything up and running¶

Follow the following steps to get everything up and running on your Beaglebone Black:

1. Download the project archive from https://code.soundsoftware.ac.uk/attachments/download/1723/bela_4-12-2015.zip

• Extract the archive (and remember where you extracted it to)

2. Make sure python is installed:

• Type `which python` in a terminal window. If not installed, follow instructions here: https://wiki.python.org/moin/BeginnersGuide/Download

• Install the most up-to-date version of the requests python package (version 2.7.0). You can get it from http://docs.python-requests.org/en/latest/user/install/
  or typing the following in a terminal window (make sure it is not currently installed):

curl -OL https://github.com/kennethreitz/requests/zipball/master && unzip master && cd kenneth* && sudo python setup.py install

if the above does not work, try this:

curl "https://bootstrap.pypa.io/get-pip.py" -o "get-pip.py" 
sudo python get-pip.py #install pip packet manager for python
pip install request

3. Create an account on enzienaudio.com:

• Go to http://www.enzienaudio.com

• Click Login on the top right corner of the page

• Create a new account

• Create a new patch and call it bbb (N.B. compiling won't work if you use a different name)

4. Make sure the Beaglebone is plugged in to laptop and open a terminal window:

• Navigate to the scripts folder cd /path/to/folder/scripts

• If running for the first time sh setup_board.sh

5. Compile your first project!

• If you are on a Mac, you can browse to the BeagleRT/resources/MacOS folder and you will find an app called BelaPdBuild. You just have to drag and drop the folder containing your files on this icon and in a matter of seconds your Pd patch will be running on the Beaglebone.
  The first time you do this, you will be prompted for your enzienaudio credentials, which you just created in the steps above.

Alternatively:

• ./build_pd.sh -i ../projects/heavy/pd/hello-world/
  This script compiles your project, uploads it to the Beaglebone and starts it.
  If you run this script with the --watch --screen flags, it will check automatically for edits in your Pd files and refresh your build automatically: no need to touch the terminal again, as long as you keep working in the same folder. For example:
  ./build_pd.sh -i ../projects/heavy/pd/hello-world/ --screen --watch

6. Create a new pd project

• Create a new folder inside the /pd directory

• The pd patch must exist in its own folder and be named _main.pd. You can use abstractions if you like.

Using analog ins/outs¶

• You can directly address the analog ins and outs from within PD (note that you have to compile and run the patch onto the BeagleBone to receive the data)

• Use the [adc~] and [dac~] objects to receive and send the data

• [adc~ 3] refers to Analog Input 0 (first two channels of [adc~] are audio inputs), likewise for [dac~]

• These inputs are sampled at audio sampling rate, so handle them as you would audio signals. (Use [snapshot~] if you want to turn them into control-rate values)

• See the example patches in the /pd folder for more information

Using MidiIn¶

• You can use the objects [hv_notein], [hv_ctlin], [hv_pgmin], which you can find in the BeagleRT/projects/heavy/pd/hello-midi/ folder. These are drop-in replacements for Pd's own objects and allow to receive Midi data from a USB device plugged into the Beaglebone.

Important notes¶

• Make sure you aren't using any unsupported objects. For a full list of objects go to https://enzienaudio.com/docs/pdobjects.html

• The Pd patch must exist in its own folder and be named _main.pd. You can use abstractions if you like.

• See the example pd patches for more information.

Have fun!