BeagleBone LinuxCNC blog

from: http://www.element14.com/community/community/knode/single-board_computers/next-gen_beaglebone/blog/2013/05/22/bbb--working-with-the-pru-icssprussv2#comment-22799

"yes, I did the inital work for non x86 installs and non-RTAI kernels, including exploring the PRU and the debugger; Charles did the heavy lifting on the PRU stepper generator.

 

The realtime requirement isnt limited to stepgens; path quality suffers badly if you dont have that.

 

EMC2 was renamed to linuxCNC because of trademark issues with EMC Corp."

from: https://groups.google.com/d/msg/beagleboard/ck4J3tl_GMs/-5e1qyNhyC4J

I'm involved with the LinuxCNC project. My works in progress are:

1. getting LinuxCNC to run on non-x86 platforms, and with a wider range of realtime kernels (when I joined it was RTAI only, which doesnt run on non-PC platforms yet)

2. splitting the package into the GUI/Interpreter part, and a standalone open source motion toolkit which can be talked to over ZeroMQ and protobuf; LinuxCNC per se remaining a user of that toolkit. This effort is tentatively called 'MachineKit'.

(1) is very far down the road; LinuxCNC now runs on RTAI, Xenomai, RT-Preempt and on vanilla kernels too (with severely reduced tool path quality, but the full configurability of the HAL environment nonetheless)

Right now we have per-kernel-flavor builds; this will be replaced by a unified binary which runs unchanged on any kernel by sporting a runtime-loadable portable realtime kernel API.

The Xenomai build for the Beaglebone is just being wrapped up from the 3.2->3.8 kernel transition, and I think we will have a ready-to-go SD image with batteries included with a very low number of weeks. This build has a stepper generator which runs on the PRU, and I think it's the best performance you'll get short of adding an FPGA. Also, the PRU code is done very clever - it supports 'tasklets' if you will, meaning you can plug in other jobs into the PRU 'task' as needed.

For folks interested in this, I suggest to keep an eye on Charles' blog which will have the latest and greatest: http://bb-lcnc.blogspot.co.at/ and the emc-developers mailing list. Now that I know that there's interest here I will announce here too.

Our goal is to provide a LinuxCNC kit for the 3D printer community, and I have started cooperating with the local reprap crowd here to get immersed in this specific mode of CNC - I have so far mostly used LinuxCNC to drive 'heavy metal', and thats still the largest user base.

(2) MachineKit: the foundations are complete (protobuf infrastructure, zeroMQ transport, extensions to the LinuxCNC realtime environment to support a message-based interface in addition to the current shared memory model of interaction), and work has started on migrating parts of the code away from the old middleware (NML) to the new scheme. That effort I expect to yield results 'later this year'; I'd be happy to hear from folks interested in cooperating on this.

- Michael

Thanks Drew!

My own 3D printer hasn't progressed for a year, sadly.  It uses the standard RepRap drive train, ie. Arduino->RAMPS, but putting a Linux board in the box for high-level duties has always been in my mind.  I'll be following Michael's progress with a lot of interest.

PS. Your thread got posted to SBC->Discussions, when you probably intended SBC->BBB->Discussions.

Morgaine.

Thanks, I'm working on getting to the clarification of desired thread location with our content team.  SBC->BBB->Discussions is pretty bare after the existing were moved to SBC->Discussions, so I agree it's confusing as-is.

Drew,

   I don't know if this needs to wait for the new forum software and/or reorganization,

but I noticed that at the knode site for single-board computers, there is a panel of "top participants",

with a link for "view all particpants", but that link doesn't show any participants at all.

http://www.element14.com/community/community/knode/single-board_computers?view=overview&ICID=knodenav_singleboardcomputers

Edited to add:  found similar issue in several other communities, so posted here:

http://www.element14.com/community/message/79062#79062/l/missing-participants-in-several-communities

There needs to be a "project rescue" area especially for non trivial or more unique projects such as 3D printers and the likes.

even putting together a well worked kit is far from trivial but if you are working on new kit it's really an up hill struggle.

Have you considered joing a hackerspace or similar ...get some physical encouragement !?

John Alexander wrote:

 

Have you considered joing a hackerspace or similar ...get some physical encouragement !?

That gave me a funny image of a cadre of hackerspace taskmasters cracking their whips over a floor of wimpering makers.

The reality is that complex projects require a significant investment of time, which can be in very short supply.  Encouragement only helps if interest is waning, but it's not in my case.  Time however is becoming ever scarcer, and socializing in hackerspaces isn't going to help with that.  Online forums are bad enough.

There are some pretty good hackerspaces in the UK, like the main London one for example, but multi-hour travel doesn't appeal, and again, wastes time.  The extra resources wouldn't help too much either as I'm quite well equiped at home.

Work on my 3D printer will continue when time allows ... and something else will then get less time devoted to it.