Looking for smallest board available with a DB-25 (for running CNC on linux)

[rick_brade]

TL;DR - what is the smallest motherboard I can buy with a DB-25 parallel port and support for at least a 1.0 Ghz processor. I also want it to be compatible with Linux. WiFi is desired, but not necessary.

background:
I want to buy this for a couple of CNC projects.
One project is for a CNC controlled plasma torch table and the other will be for my CNC controlled milling machine. Here's a picture of what my milling machine looks like:



And here's an example of what a CNC controlled plasma torch table looks like.



For technical reasons, CNC hardware works best with a "Realtime Operating System" so that signals are sent to the stepper motors at precisely the right time via the parallel port. The Linux CNC community has a custom compiled version of Ubuntu Linux compiled specifically for the purpose. Unfortunately even with their custom code, sending signals to the machine controller device via USB is frowned upon because the timing isn't always consistent enough. Unfortunately, that rules out using a USB to Parallel port converter, so that's why I'm looking for a native DB-25 solution even though they're getting harder to find on new computers.

I'm hoping to find a motherboard that is small enough that it could fit inside the enclosures that contain the rest of the CNC electronics such as the fist-sized capacitors, power supplies, stepper motor controllers, etc. The enclosures I have are approximately the same size and shape as a Mid-Tower PC. Here's an example of one:





Most people run external computers, but I'm hoping to keep everything in one enclosure.

Ideally, I'm hoping to do all of my CAD design on a separate workstation and transfer files to the mini-computers at my CNC machines.

Any Suggestions?

[Vectronic]

DB25, ~1GHz... why not go to your local garbage dump, or recycling depot, pick up some HP desktop from 2005 or something?

I've got 3 PC's here, all MicroATX (244x244mm), all with DB25, all with >1GHz CPU's... and I'd happily throw all 3 of them at you if you lived next door.

[dave_the_nerd]

I wouldn't put it in the box with the other electronics. They might create enough RF to screw with the computer parts. (And WiFi is for sure out of the question.)

Any reason something like this wouldn't work?:

http://www.newegg.com/Product/Produc...82E16815104211

Otherwise, what Vectronic said is correct - probably cheaper to find an older PC with a parellel port and tear it down.

Or:

http://www.geeks.com/details.asp?inv...1TY-BO&cat=MBB

[Insert_Nickname]

Smallest as in size? or cost?

In either case the Intel DH61DL is worth a look...

Otherwise dave_the_nerd has a fair point about using an expansion card. Parallelport cards are available as both PCI and PCIe cards.

http://www.startech.com/Cards-Adapters/Parallel

[dma0991]

Gigabyte GA-D525TUD fits the description best but you'll have to know if the Intel Atom would be able to handle the custom code. It will run Linux natively but I meant in a performance standpoint. There are new boards that do come with parallel ports. Try looking at Gigabyte's H61 lower end models, they work with current Socket 1155 processors. The most cost effective solution would be to use a Parallel port PCI card with any PCs you might have now, assuming that there are no similar issues related to the usage of USB ports.

[Sheep221]

Get an i3 and mATX board, it will fit on the backside of your control case.
The fastest way to transfer data between computer and movement electronics is via cross-hovered UTP cable(if you interface for it).

Originally Posted by Vectronic

DB25, ~1GHz... why not go to your local garbage dump, or recycling depot, pick up some HP desktop from 2005 or something?

Don't buy some shit old stuff there. I have CNCs in work equipped with atoms, via C3 and similar, and they are so slow and annoying to use, I really thought that machine worth of $150K will be equipped with something better. Peeps think that rendering NC code is so simple while it's not.

On other hand I'm abit confused with your CNC, it does have also some sort of manual mode? Asking because of all those levers.

[pantsaregood]

There's absolutely no reason to buy an i3. This computer is intended to perform a simple task consistently. An Atom would handle it fine.

[Vectronic]

Originally Posted by Sheep221

Don't buy some shit old stuff there.

Whoa there... I don't know where you live, what weird laws there might be, but north of 49th, it's free.

Most garbage dumps have a section near the gate where you leave things like PCs, TVs, Microwaves... may or may not be functioning obviously, but free if you want them.

There's also usually at least one (words failing) dedicated electronics place where you can drop off your old equipment, some of them specifically for computers, where you can get a fully working system for next to nothing, occasionally nothing, or by bringing in your own stuff as trade.

Nevermind garage sales, and so forth. I don't see the point in buying a new system when there are plenty of used ones that are more than enough, and you won't be that bothered if/when they die, or you spill oil on them or whatever.

No offense to the OP, but it's not exactly a lab coat environment. The older the equipment the better usually, it's tougher, simpler, easier and cheaper to fix.

An even older system that mentioned so far might be better, if you can get a motherboard with an ISA slot or two, you can create your own expansion cards with rudimentary soldering skills and junk parts. This was, and still is done in CNC/CAM, should be possible with LinuxCNC, is possibly with TurboCNC and the likes, and you can still buy new motherboards, even Ivy Bridge, with ISA slots for that reason.

If OP wants to go the money-route, get a Toughbook or similar, and one of these. Durable enough to drag around the shop, easily enough power (i5's, GB's of RAM, etc), disconnect use it for whatever else.