Bela mini USB port as audio input

scmint

Hi!
I was just wondering if Bela mini's USB A port can be used as audio input that can be hooked up to a USB microphone?

I have a µMoth that functions like a live USB mic (with firmware switch): https://www.openacousticdevices.info/audiomoth

And trying to see if it's possible to use it with bela mini as an input device.
Wondering if anyone has tried using USB mics with bela mini before me?

Many thanks in advance!

giuliomoro

You should be able to, but you'll add some overhead and increase the latency.
You'd need to open the usb device via alsa and then shuttle the data back and forth with the Bela backend .
Something like this:
https://github.com/BelaPlatform/Bela-ALSA-bridge

What's your use case?

casi

Hi,

I’m a contributor to scmint’s project. Thanks for your answer.

We are looking to feed live environmental sound into a SuperCollider program, where it will be processed in real-time in combination with preexisting recordings. We’d ideally use the same microphone for the live input as the preexisting recordings were recorded with (the MicroMoth), hence the question.

Low latency is no requirement, so we'd be curious to see how this could be set up. The link appears to be dead, is it a private repository?

Thanks!

giuliomoro

Link is now public. Are you planning on using any of Bela's digital I/O or analog I/O capabilities?

robinm

giuliomoro
Well I can say we are trying to prioritize size first (the tinier, the better, that's why we're mostly looking at MEMS mics), then frequency response range (the wider, the better) and then omnidirectionality if possible. That's why the uMoth or Audiomoth seemed promising, but any device that is small enough in size and sensitive enough to provide some clear audio would be ideal. If it can output analog audio it'd be a huge advantage for connecting it to Bela running SuperCollider, but if this isn't possible (seemingly as with the uMoth) then we'll have to create surreal connections between Bela and the microphone. If you have suggestions please let us know, we have a couple of Adafruit options right now that involve using I2S connections with Bela but we're still open to other alternatives 🙂

giuliomoro

I was asking whether you need to use any of Bela's analog inputs or digital I/Os alongside your audio processing? If the answer is no, then you could just load a stock BeagleBoard image and use it via USB using the regular ALSA drivers. You won't have any low-latency guarantees (which you wouldn't get anyhow via USB even used in combination with ALSA), but it should work. The BelaMini cape becomes somehow useless at that point, except that it provides the USB host port on top of the PocketBeagle.