Bela IO - BeagleBone Black Audio DSP

Started by GovernorSilver, January 28, 2016, 11:08:05 AM

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Seems like there's a few hardcore engineering types here.  This might be of interest


Bela is a  BeagleBone Black daughterboard (cape) - great platform

What is BeagleBone Black?
BeagleBone Black is a low-cost, community-supported development platform for developers and hobbyists. Boot Linux in under 10 seconds and get started on development in less than 5 minutes with just a single USB cable.

Processor: AM335x 1GHz ARM® Cortex-A8
4GB 8-bit eMMC on-board flash storage
3D graphics accelerator
NEON floating-point accelerator
2x PRU 32-bit microcontrollers
USB client for power & communications
USB host
2x 46 pin headers
Software Compatibility
Cloud9 IDE on Node.js w/ BoneScript library
plus much more


Kickstarter project went live and is already fully funded with 31 days to go.

If I can overcome my fear of making physical things, I might spring for a starter kit. 

I got poor grades in EE lab classes.  Not confident I can figure out a solution to house the unit and make the connections that I want for the I/O ports and such.  Ikea furniture is about the most complex thing I can build with my hands and not screw something up.

Still, looks like it might be a more robust platform for running Pure Data patches than the considerably more expensive Organelle.

Bela is an embedded system for real-time audio processing with ultra-low latency. Based on the BeagleBone Black single-board computer and featuring a custom hardware and software environment, Bela integrates audio processing and sensor connectivity in a single high-performance package.

Bela is an ideal platform for musicians, instrument designers, audio enthusiasts and interactive artists.

Bela was designed for audio hardware projects, but it doesn't stop there. Bela is ideal for any project that requires ultra-fast processing of multiple streams of data for maximum responsiveness. Bela is the core of many electronic musical instruments, but has also been used for kinetic sculpture, interactive installations, even a game played in an analogue oscilloscope.

In this video Giulio puts Bela through its paces, showing some of the possibilities of interfacing Bela with an analogue synth. He uses libpd to run PureData patches on the board, patching the analog outputs of Bela to the CV ins of a Doepfer Dark Energy II. This demo just scratches the surface of what's possible when Bela is used to control an analog synth (or when an analog synth is used to control Bela). It should serve as a good introduction for what can be done with the board out-of-the-box, and show how easily a Bela-based module would be to get up and running.

Giulio demonstrates some fun ways of taking control of the Dark Energy via a PureData interface. He then shows how to make things physical and connect sensors to take control of the analog synth. To take full advantage of the CV ins on the Doepfer we would need some extra circuitry but with some simple patching leads we can still achieve a lot. The frequency inputs on the Dark Energy are scaled to 1V per octave — the analog outs of Bela can produce 0-5V so we can cover a 5 octave range.

The video also includes a demonstration of how to take CV out from the analog synth and feed it into Bela. Precautions need to be taken here as the analog ins on the Bela board only tolerate 0-5V. The specs of the Dark Energy report that it gives out 0-6V but on measuring it is more like 0-8V. This would be enough to turn the Bela board into a Bela brick so we need a protection circuit. Giulio shows how to use two resistors to divide the voltage down, plus a diode from analog in to 3.3V to prevent the CV out of the synth from exceeding 4V.

Bela Starter Kit - PREORDER, shipping late February 2018


This is a PREORDER for the Bela Starter Kit. More boards are on the way, expected delivery late February 2018.

The Bela Starter Kit contains everything you need to get up and running with Bela:

1 Bela Cape
1 BeagleBone Black rev C
2 x 3.5mm jack audio adapter cables
1 Mini USB cable
Latest image flashed on the eMMC of the BeagleBone (no need for SD to get started)
This price includes free 1st class shipping anywhere in the world. To add signed/tracked delivery, please select that option at checkout (£5 for UK/EU, £8 for everywhere else).

This kit is also compatible with the Bela Mux Capelet (which increases your analog inputs from 8 to 64), and the Bela Audio Expander Capelet (which converts your analog I/O to additional audio channels).



The original Bela board has everything you need to start creating beautifully interactive applications. With 8 16-bit analog I/O and 16 digital I/O you can hook up all your favourite sensors and devices, and get programming with our browser-based IDE. Bela is compatible with our multiplexer and audio expander capelets, and has on-board stereo amps, making this our most fully-featured system. Available as a starter kit (full system of BeagleBone Black, USB cable, Bela cape and two audio adapter cables) or as the stand-alone cape.

Stero audio I/O
8 channels of 16-bit analog I/O
16 digital I/O
On-board speaker amps


In 2018 we condensed all the most popular features of Bela into one tiny system that fits in more places than ever before. The Bela Mini is 1/3 the size of the Original Bela, but still powerful - it has 8 16-bit analog inputs, 16 digital I/O and stereo audio I/O. Bela Mini uses the same Bela software as the original, so you still get access to our browser-based IDE in a much smaller form factor. Available as a starter kit (fully assembled board, USB cable, SD card and 2 audio adapter cables), or as a standalone kit.

Stereo audio I/O
8 channels of 16-bit analog input
16 digital I/O


CTAG is a multichannel audio system for Bela, developed in collaboration with Henrik Langer and Robert Manzke from the CTAG group at Kiel University. There are two versions available, CTAG FACE (4 channels in, 8 channels out) and CTAG BEAST (8 channels in, 16 channels out).


If 8 channels of analog input aren't enough, expand up to 64 channels with the Bela Multiplexer Capelet. (Compatible only with Bela Original.)


Turn your 8 analog I/O into 4 additional stereo I/O with the Bela Audio Expander. (Compatible only with Bela Original.)

Digital Larry

My Bela's sitting in a drawer somewhere.  I did actually at one point get some Faust programs working on it which was kind of incredible the backflips I had to do, but with the patient guidance of a guy at the Bela forum I pulled it off.  I am much more amenable to writing software for stuff than building things with a soldering iron.

I also got some ESP-32 audio board (apparently a reference platform for something like an Alexa intelligent speaker) running with Faust programs.  I even hacked in OSC support so I was able to control it over the wireless LAN using TouchOSC running on an Android tablet.

Unfortunately, the board itself was very noisy and spewed all sorts of hash when OSC was coming in, and the complexity of the code I could get running on it was not even on par with an FV-1.  I got an echo with a flanger in the feedback loop and wasn't able to get much further.  Oh well!

All the code I did is over at Github.