Bela rev. B2 suddenly died

minnowahaw

Hey hi Giulio et alii,

I have been transferring my working code from a Bela mini (because its audio input died, see other post) to a normal Bela rev. B2. I am not using the audio input with the phantom power unit and the schertler contact microphone, since I am still investigating what caused the audio input to die. So I am just using some test samples for my wearable instruments and I am using a Trill Hub with 4 flex sensors and 4 flex crafts. After compiling the TrillUGens for supercollider I started to work on the code and get the 4 flex sensors to work again - the Bela craft was already working. Now all of sudden thet Bela (revision B2) stopped working. When I plug the cable in, very briefly the blue PWR light flases and then immediately dies, while I hear a little crack on the audio channel.
It's quite a warm day (it goes until 30 - 31 degrees here on my studio underneath the roof), so could it be overheating? If I let it cool for a while, it still doesn't boot.
Or does it have something to do with the Trill setup with 4 flexes and 1 craft? Is that too much? On the Bela mini it was working.
Thanks for your answer. I now only have one Bela left for my project, so I need to be careful.

All the best,
Sjoerd

giuliomoro

Sorry to hear this died.
Hmmm how are you powering the Trills ?

minnowahaw

In the case of the normal Bela I was using the 3.3v pin from the four I2C pins. On the Bela mini I was using the 3.3v socket. I am a bit nervous now to start using my last Bela.

giuliomoro

30-31 degrees won't be a problem, the device is rated > 70ºC and I use it all year round in 32ºC and it's been used in the Arizona desert without problems. Even then, exceeding thermal limits should result in the CPU shutting itself down.

Did you try to power it up without the Trills ? Also, try to carefully remove the cape from the BeagleBone Black and see if it boots without it.

minnowahaw

giuliomoro yes, I tried that. It still does not boot without the trills. I will try to boot the Beagleboard without the capelet

minnowahaw

For this prototype setup I left the input source out for now (until I solved the audio input death reason on the Bela Mini) and was just working with 2 channels out and 1 craft and 4 flexes via the Trill Hub. I powered them via the I2C pins, as you see in this picture:

minnowahaw

minnowahaw OK, without the capelet it DOES boot. So I guess the capelet is broken then?

giuliomoro

oh that's an interesting development, I didn't think it would make a difference ... fun fact is that the trill pins are not even used on the Bela cape: they are simply passed through to the BeagleBone Black ...
What's connected to the audio output? I assume you've been resting this on a non-conductive surface (like the wood in the picture) or have you placed it on something conductive (metal, conductive fabric)?

Either way, email us so we can help you out.

minnowahaw

giuliomoro
The output was just going straight into a DI and then into the mixer, so that would not be the problem. The Bela has been resting on the wooden surface and inside a 3d printed container. But the thing I suspect are these metal ribs that the costume designer I am working with has come up with. We did some interesting tests with the putting a flex around this metal ribs for a wearable design and this was always working great. But maybe this caused in the end some kind of short circuit? Should we avoid using the flex sensors on metal? I thought I read they could be applied on any surface and with the Bela mini we have been using this combination without any problem for months. Or could this also be the reason why the audio input of the Bela mini died?
Here is a picture, I opened up this prototype flex with the rings to take a picture:

giuliomoro

Any shorts that may occur on the Trill side shouldn't break anything, as all used pins are 3.3V safe and only 3.3V is going to the Trills ... that's of course unless there's some severe electrostatic discharge situation going on, but then I'd expect Trill to fail first and then the BeagleBone, but it doesn't make sense to me that the audio in (of the Mini) or the whole cape (of the Bela) would fail ...

So I am a bit puzzled here ... Are there any other voltages being provided anywhere?

minnowahaw

giuliomoro No, I am only using one Trill Craft and four Trill Flexes with the 3.3 volt supply in this setup.

giuliomoro

Any textiles or other materials that can store electrostatic charges and get routinely rubbed so that they accumulate charge that then gets discharged on the boards ?

minnowahaw

giuliomoro No, I was just prototyping at the moment on my work table....