Here's an example of a program that can run stand-alone on Bela, receive OSC and set LEDs on a Neopixel-like strip. It comes with a Pd example of a 16-segment VU-meter.
https://github.com/giuliomoro/O2L
Note that you should either run this Pd example on your host or, if you run it on Bela, rename the file to _main.pd and put it in a different project.
The mods you'll need on your Bela cape involve bending out pin P9.30 (which is normally the data line coming from the codec's ADC). This is a potentially destructive operation if not done carefully: it may be complicated to bend the pin back in place if you need the audio input again in the future. If possible, try bending it out without causing a sharp angle, e.g.: using a pair of pliers to shape it into a more rounded shape. If this pins should break now or in the future, you can probably bypass it with a jumper wire soldered to the back of the beaglebone ... not ideal but better than nothing.
You'll also need to install a modified device tree overlay on your board. All of this is explained in some more detail at the top of the main.cpp file.
You can test O2L (and all the above mods) by running a Pd patch such as the enclosed one on your host, while running this program on the board from the IDE. Once that setup is tested and works fine, in order to run a regular Bela program for audio/sensor processing alongside O2L, you will need to run the O2L program as a service on the board. See here for details on that.
