EMC2 running on Raspberry Pi?

I compiled a PREEMPT_RT kernel for the Pi3 by patching the Pi kernel sources with the RT patch from kernel.org, and on top of that I compiled LinuxCNC master. I could have used MachineKit as well, but I do not see the advantages of that project over LinuxCNC and I also have a CNC mill and lathe running on LinuxCNC.

I am not running a GUI with OpenGL preview (cannot fit that on the 800x480 Pi touchscreen), thus so far graphics performance is more than adequate.

If anyone is spending >$2000 on a CNC router + tooling (and it is hard to build something decent for that budget) I do not see the point of using a Pi for that. Once all the costs are added up, the extra cost of a conventional PC-based controller setup is peanuts. A suitable refurbisched PC costs $75 (or even new mainboard+memory+storage can be had for <$200), Mesa hardware is well build and not extremely expensive either and a couple of E-bay sourced Leadshine DM drives are doable as well.

For a 3D printer, diode laser cutter or people like me who like to play this is different. There even the Pi3+touchscreen+powersupply+memory card+L6470 stepper drives can be described as 'expensive', and size matters.

this little board could be an alternative to the raspi?
www.up-board.org/up/

The advantage of Raspberry Pi is not in its price but in its size. I think the performance of the latest version is more than enough to handle any cnc machine. It has a powerful CPU as well as a GPU and has interesting peripherals, especially SPI.

I work on universal boards based on FPGA for Raspberry Pi that can be controlled from any program that can communicate with the SPI port. One of the uses is LinuxCNC.

I do not see the meaning of Machinekit and I would rather use Linuxcnc. Would it be possible to share the Linuxcnc disk image or make a more detailed procedure to how compile it?

Boards like that Up^2 sound really good to me. But like others such as the Udoo x86 they are still in preorder or just very expensive.

Regarding LinuxCNC on the Pi3: my SD image contains too much 'experimental stuff' to be able to safely hand it over. My Pi is used to all that misuse, but yours probably burst in flames :laugh:

However, I can try to build .deb packages for the kernel. Never did it before, so no idea how complicated it is.
In the meantime you can get a working realtime kernel from www.frank-durr.de/?p=203
That kernel works fine, it only lacks support for the Pi3 WiFi. This is why I took the Pi foundation kernel sources and patched it with the closest matching PREEMPT_RT patch. Building and installing the Pi kernel is described here: www.raspberrypi.org/documentation/linux/kernel/building.md

Building LinuxCNC is described here: linuxcnc.org/docs/devel/html/code/building-linuxcnc.html
Once you get to the ./configure step, make sure to use ./configure --with-realtime=uspace.

I shot a small video yesterday:



Mind you: preliminary testing of unfinished stuff.
This is basically the first time I run the motors at speed. No tuning of the PID loops or dSpin drives has been performed yet, which is audible. At 1G acceleration step loss happens at 800mm/s which is waaaay too fast to be comfortable anyway; the entire travel range is covered in a fraction of a second at that speed. Video is running at most at 300mm/s.

After several hours of running LinuxCNC and the Pi didn't miss a single beat.

I also installed a one system yesterday, and besides the above-mentioned problems with response in use with large file, the machine worked nicely



One with large gcode