All true, the controller is nothing special in terms of how it drives the
steppers. This is designed to be a minimal starting point, BUT it is also
designed to be stunningly reliable and still have good SPEED performance.
The PC sends path commands and the PIC does the timing and production of the
steps to follow that path. In this way, variations in the execution speed of
the PC software can not affect the operation of the mill.

The software is really nice, very easy to use, simple and clear. Just gets
the job done.

Your setup sounds like a great idea, if you are willing to put out $30 for
the controller PCB, parts kit and software, you could be up and running
quickly.

If the accuracy and repeatability of your mill is enough, then it could be a
great lower cost alternative. I have my doubts about doing any sort of SMT
PCB with that but I'd love to be wrong and there are other applications
where this controller could be used for lower resolution projects. E.g. wood
carvings or filigree (sp?) metal work. The controller software does read
HPGL as well as board files so just about any art pattern can be milled.

Are you interested in producing that mill rather than just offering the
design? The market I plan to target does not want to spend time building it
themselves.

---
James Newton, massmind.org Knowledge Archiver
james@massmind.org 1-619-652-0593 fax:1-208-279-8767
All the engineering secrets worth knowing:
http://techref.massmind.org What do YOU know?





> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Denny Esterline
> Sent: 2004 Jul 20, Tue 10:49
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: (will be) Small CNC mill, controller and
> software for ~$500
> Importance: Low
>
> I might be in a position to help you with that. My time's a
> little limited right now, but I just happen to have a
> homemade circuit board milling machine setting here on my
> desk waiting for me to write the (PC) software.
> (not my favorite job :-)
>
> Made from 1/2 inch thick MDF, ball bearing drawer slides and
> hardware store 1/4-20 threaded rod- cost of materials less
> than $40 USD.
>
> Seems like it'd be an easy option for testing your driver
> board / software, plus we could arrange to include plans for
> it with your driver.
>
>
> I am curious as to the specs of your driver (V/A?), from the
> picture it would seem you have a PIC driving discrete
> transistors? Are you using any kind of current feedback? Or
> L/R topology? I'm also guessing it's for 5/6 wire unipolar
> motors, yes?
>
> -Denny Esterline
> (Michigan USA)
>
<SNIP>

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