LinuxCNC on Raspberry Pi 5

As far as my testing has shown, on my cobbled together 7c81 clone SPI works on the RPi 5.
I received my RPi5 around Nov\Dec 2023 and can't say I've noticed any hardware issues. Booting from a NVME drive has shown no issues, I've run octoprinter on it, once again no issues.
Speed wise even when running via a SD card is night and compared to my RPi400, which has a slightly faster CPU than the RPi4. Actually to be fair it is a bit of a beast.
No trouble building Linuxcnc packages, even with 2 cores isolated, tho I suspect this may not be needed when connected to a Mesa board.
Bang for buck a PC from the last ten years is far better value.

Personally I'm still undecided whether to use my clone with an EPP interface with a PC or with the RPi5 via SPI.

To tell the truth I'm in 2 minds whether I actually want to CNC the lathe, the only reason I started to convert it is the AUD $600 to get hold of a new screw, maybe it would be worth it, if only to have one of the few Myfords with a leadsrew that isn't worn.

Back to topic.
Whilst the RPi is able to run Linuxcnc not a lot of info for the official Raspberry Pi foundation images are applicable, as it is only really the RPi kernel sources that are used, needed for use of loading overlays, the rest is pulled from Debian arm64 repos. Config.txt must be edited to enable the SPI interfaces. And Linuxcnc will need building from source to have the hm2_spix driver. Last time I looked the pre built packages pre dated the new driver.
Re Tommy's comment regarding a small SBC controlling a large CNC machine, how would you feel riding a bike at 220-240 kph ( on a race track of course) that's ecu is controlled by a Motorola microcontroller ? Cos that's the brains used in a lot of Ducati's and Moto Guzzis around 2000 vintage. Very hackable, very easy to download the operating code off and disassemble. Even a fully unqualified shit kicker like myself was able to do, the one and only time I did anything with C Sharp.

I'm going to assume model boat building, other wise I'd imagine you would have researched the larger machines required for human scale boats. If all you want to do is profile cuts, eg bulkheads and the like and you aren't using timber over 3mm or so I would suggest a 10w - 20w laser cutter might be the better choice. No need for Linuxcnc as the supplied controllers do a fine job, I have one myself. Far easier to deal with the "fumes" from a laser cutter than the sawdust you would get with a router.....and far gentler on the thinner timber components as the cutting forces are reduced to practically zero on the material being cut.
At a recent exhibition of local model boat builders I met a Hungarian gentleman who did some amazing work with a hand held rotary tool, timber was carved so thin as to be almost see thru. When asked whether he be human or magician, he puffed out his chest and proudly stated "I am Hungarian".
Tho I would suggest a honeycomb type bed and air assist to reduce scorching and a build up of residue in the cut.

Hello cornholio,

I'm actually building both types of boats: model (1/4 scale) and real-sized; the first being a prelude to the second.

The RC boat starts with a "short kit" bought off of eBay - just the frame members (laser cut). I just have to put a skin on it.

I would dearly love a laser CNC machine to cut out the frame members for the real boat but many boat plans are not digitized (like mine) so the first thing I need to do is to turn a CNC machine into a giant "digitizer". Does experience doing that exist? It does seem doable and if I create the files I might be able to find someone to laser them for me for a price.

Thanks,
Tom

I’d look for a CAD package that lets you import an image and “trace” it. Bear in mind that the time it takes you to do that it maybe just as quick to cut the various members the traditional way.

Much respect for the traditional way but I would like to come up with a 21'st century option. Digitizing from the image sounds good. I'll look into it.

Thanks,
Tom

I'm not sure I could make an image/picture that was not materially distorted but I will look into ways to do it.

I would like to run an option past you:

-- Tape the plans to the bed of the rig.

-- Replace the cutter/lens with a stylus.

-- I just saw a "CAM USB camera" online that gives you a view of the exact place where the (stylus) hovers over the plans. (I can not find it online right now...)

-- Then:

    -- Jog the steppers with a joystick to place the stylus over the "start" of the tracing

    -- Touch a button on the joystick to register the current location on the plans/bed

    -- Jog the steppers again to get to another point on the plans and press the button

Observations:

  -- Straight lines would be easy; curves would require help digitizing gracefully, but I have some thoughts

  -- The file of points would have to processed into a file of "cuts".

  -- Plans involving multiple parts would have to be digitized a part at a time. The parts would then need to be laid out on (a 4 x 8 sheet of stock say).

Thoughts?

Thanks,
Tom
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