Suggest a laptop motion controller

[beanbag]

I'm looking to throw together a small CNC system to make a few simple parts. I initially just want a simple motion controller to run a 2 axis CNC lathe stage I plan to build. This means it doesn't need to be super complicated nor fast. Later I might transplant it to a 3 or 4 axis little mill.

I need the system to be portable, so I want to use my laptop. The options I see so far are:

1)Get a pcmcia to parallel port card to run mach
Cost: $25 + Mach is free if I keep the code below 500 lines
Reviews seem to be mixed on whether these work well or not. No, I am not willing to strip down my laptop to minimize interrupts and etc.

2) USB smoothstepper
I read some complaints about it, but I don't know these days whether it is still OK or not.
Cost: $155 + Mach is free

3) Planet CNC USB controller
This looks cheaper than the smoothstepper, but then I have to pay another $100 to buy that guy's software. I don't have anything against it yet, but I really don't want to d1ck around with having to learn yet another program.

4) Kflop
costs the most and I don't need frickin 8 axes.

5) other suggestions?

Basically I want to keep the effort and money minimal on this in case I abandon the project for something else. This holiday weekend I soldered together a Linistepper and wrote some Labview code + USB DAQ I have to get it to control a little motor. OK, that was cute and all but in retrospect I should have just bought a Polulu and been done with it.

Edit: I also have an arduino board if that means anything.

[djc]

...The options I see so far are:

1) Get a pcmcia to parallel port card to run mach
Cost: $25 + Mach is free if I keep the code below 500 lines.

First, you should very strongly disabuse yourself of the ludicrous notion that Mach is free. It is not. If you find it useful, you are obliged to support the vast amount of development and resources provided and pay up. Do not be a tightwad.

Can you create a DOS partition and use TurboCNC (though I don't know if DOS supports PCMCIA)?

[macona]

It is very easy to go past 500 lines in mill mode, and I think it has a 200 line max in lathe mode in demo. If you want free look at EMC2.

SmoothStepper is probably the best bet if you really must run it from a laptop. Even a PC card parallel port does not guarantee good performance. The machine still has APCI running and that messes a lot of things up. If you need a small machine use a mini-itx board with possibly an atom or a coreduo processor.

Arduino is useless for cnc. It cant handle what is needed.

[beanbag]

I think the computer really does need to be a laptop for portability reasons. A "desktop" computer, no matter how small, still requires a monitor, keyboard, mouse, and extra power cords. From what I read, a smoothstepper queues up commands, so does it really matter if the laptop spits out commands at irregular intervals?

I didn't consider going to another OS, but maybe that might work. I would like to stay in windows if possible so I can quickly re-run whatever cad/ cam program I use to tweak the g code.

[macona]

The computer will send out the signals over the usb just fine. Its just mach directly access the hardware ignoring a lot of OS.

Smoothstepper is probably the best way to go now that it has backlash comp.

EMC2 does not support any of these devices because of the latency. With EMC you are stuck with the parallel port and a few motion control cards.

[beanbag]

Thanks for the suggestion. Have you also looked at the Planet CNC system?
http://www.planet-cnc.com/index.asp?page=shop

[macona]

It looks interesting. It has backlash comp. Also has rigid tapping.