There is a bug.  

It affects most common distributions of Machinekit.  It's not their fault, and the core issue seems to reside within the kernel.

Machinekit is what all of my 3D printers run.  The only one which is currently operational without parts being stolen from it...  and the one which has printed everything thus far, is the M2.

I got bit by the bug.  It's a bad one.

I've been running  the printer pretty much non-stop for several months now, so this is not a common thing.  In fact when this bug actually occurred the last time about a year ago, I contacted one of the maintainers of Machinekit personally to see if they could use my failure to gather data.  Sadly, they were on the road and not available to do so, so I rebooted and moved on.

So enough backstory. 

The kernel driven device mapping for the ADC for the Beaglebone can very occasionally, just stop reporting actual values.  There is code in the Machinekit distributions designed to detect this occurrence and shut things down.

I don't have it.

I wrote my code to run the M2 before this, and it is complicated by my standards at least,  Updating my code to include the safeguard would mean rewriting it.  I did not do that.  So this is really totally my fault.

Anyway, long story short... My ADC stopped responding.  My 80W print head was on and heating at the time.  

I was in the room, but did not notice the issue.  The print head is water cooled and so it was not until I eventually ran out of water several hours later that it became one.  It then promptly ate itself and started to smell funny at which point I shut it down... too late.

It takes about a day to rebuild the print head, but I'm burned out already.  I'll be doing that tomorrow.

In the meantime, I did generate a new revision for the Buddha feeder,, started, completed, and subsequently abandoned another version, and then started a new project for a drag feeder.  All are now Lego mount.  

The drag feeder was really easy comparatively, and probably will be much more useful to the general pubic than the Buddha at this point.  I'm rather proud of it.  It's totally Lego.  Modular building blocks.  :)

Unfortunately, I can't print it out, yet, but I have posted the code.