EMC2 running on Raspberry Pi?

andypugh wrote:

mungkie wrote:

I have done it.

You are aiming for 10,000 backers? I can't help feeling that that seems a little ambitious.

Yes, I think I had a strategy in that, I am not really sure I want the hassle and work involved so 'think big and fail'

Really the number is based on what the motor manufacturer told me for bulk discounts, and the thought that it will give me an idea of numbers that are actually interested in funding. I can then start another round of funding with a higher price but lower volumes. If I went for 1000 backers the price would end up around $200. When that option fails then finally I will try just asking for funding for the test hardware only and no one gets any perks and has to sort out their own hardware.

In case anyone is still interested in linuxcnc on the rpi1 I was trying to recover some work to use in tests on the rpi2 and decided to make up a tarball that should run fairly well.

I posted on a thread on the rpi forum last night:

www.raspberrypi.org/forums/viewtopic.php...09&p=700706&#p700706

direct download link is on a friends soundproofing web site soundproofingforum.co.uk/rpi_linuxcnc/linuxcnc-RT-rpi1.0.tbz

Hello,

Please update the page wiki.linuxcnc.org/cgi-bin/wiki.pl?RaspberryPi

To new Raspberry Pi 3

www.stewright.me/2016/03/raspberry-pi-1-2-3-compared/

Thank you.

Not related to the wiki but it might interest some people: I am having little trouble running LinuxCNC on the Pi.

Example:


This is for my 3D printer which is currently being designed and constructed:


GUI is custom GladeVCP and not finished yet. I needed a custom one because the standard Pi screen measures only 800x480 pixels, which is not enough for the standard ones, and I don't need a full featured CNC GUI anyway.

Stepper drives are ST L6470 types, interfaced directly to the Pi's GPIO header, no additional hardware. For more serious motors one might consider the PowerSTEP01 series: 80V/10Amp, same SPI interface, slightly different register mapping.
For the temperature control / sensor readout I cheated, and used an STM32F103 Minimum System Development board ($2,50 on fleabay) connected through USB.

So far I am quite happy with the Pi3 running LinuxCNC. Especially when interfaced with PowerSTEP01 it would happily drive any size router or mill.

Early picture of the electronics section:


The Pi+screen is mounted on the front panel, stepper drives are directly behind it, things are powered by a 24V supply, and there is a breadboard that contains the STM32F103 board, a couple of MOSFET's+drivers, a couple of triacs for the 230VAC heaters, and two DC/DC modules to generate 5V (Pi+screen) and 12V (fans) from the 24V system supply.

The first version never interested me much, and I don't have one either. Too little of everything.
This changed with the Pi3 though. 'disk access' (to the SD storage) is still terrible, but for the rest it is performing quite nicely.

Realtime performance of the Pi3 is mediocre, though. I compiled a PREEMPT_RT kernel bij applying kernel.org RT patches to the Raspbian kernel sources, resulting in a 4.4.39-rt49-v7+ PREEMPT_RT kernel. Works fairly well, but there are latency excursions from time to time. With the velocity generators in the stepper drive chips themselves this is no issue so far. I only wished that LinuxCNC would measure the actual cycle time and used that info for the TP instead of just assuming it is 1ms or whatever the servo period is set to. Then a lot of jitter would be no issue at all as long as there is an upper bound on the latency.

I have considered trying an Udoo board with i.MX6, but RT jitter seems to be not much better on that board, it is more expensive than a simple micro/mini-ITX x86 and the Pi ecosystem is huge.

Hi DaBit,
thx for that informations. I'm very interesstet in using a Raspberry instead a old PC in the future, but I'm not to much "inside" electronics and programming. For that i have a few Questions how you released it.
Which basic OS do yo use? raspian or a other debian for arm's?
Which LinuxCNC you use, - 2.7 or 2.8? or
If i understand right, you conect the steper drivers directly to the raspberry, without any "breakeout board". Is that also possible if i want to use DRV8825 drivers?

Only thing that needs to be done to make linuxcnc run really well is for someone to make a wrapper library to allow python opengl use the rpi openGLES GPU.

Hi all,
I want to ask about opengl on Raspberry Pi
I use LinuxCNC on Raspberry Pi with our boards pidicnc. There is problem with graphic performance. When I loaded bigger code, the graphic performance and a response of whole linuxcnc is low while performance of RT tasks is OK. Here is video from my hobby mill:
www.dropbox.com/s/ugv7nkg3vxayqq0/VID_20170322_084927.mp4?dl=0
What do you think? It is caused by some setting or there is something bigger unsupported on arm platform?

We also talk about it on:
forum.linuxcnc.org/27-driver-boards/2974...trol-system?start=20

Any idea will be really helpful for me, because it is very restrictive for our product
Thanks Viktor