[Coco] [coco] The next coco3.....wish list

[Gene Heskett]

On Friday 03 October 2014 10:30:36 George Ramsower did opine
And Gene did reply:
>   With my "wish list" coco4, that can all be done with a plug-in
> cartridge. The same as has been done for years. This does not need to
> be built into the computer.
>   There's no real need for internet connectivity when a PC can do that.
> Then the file/s can be transferred to the coco via a plug-in RS232 card
> or the latest RS232 high speed driver for the built-in RS232 port.
>   Basically, it would be a very fast(internally) Coco3 as we all know
> it. All these add ons can be plugged into the expansion slot.
>   I see no need for networking but it can be done via an RS232 port. I
> have NEVER transferred HUGE amounts of data in/out of a coco except
> when doing a backup.
> 
>   I guess if I could have Basic09 that would run on this PC and access
> a home built I/O board so I could talk to the outside world as I can
> on my coco, I could give up on my coco but, it's the only way I can
> monitor switches, control stepping motors and do things, simply. It's
> just that the Coco is just too slow for what I'm doing. Everything
> else is fine. I don't mind a couple minutes transferring files to this
> PC for backups and loading files back to the Coco. I've got the rest
> of my life to do those things but, when the Coco is actually working a
> project, speed does count.

And thats where a 275$ computer, based on the intel atom cpu, is the hands 
down winner when it comes to driving cnc machinery.  I bought a pair of 
ARK shoeboxes with the D-525MW board in then, 250Gb drives, an optical 
drive so you could install the os of your choice as it doesn't 
automatically come with a copy of windows.

It also has motherboard ethernet at 100mbits/sec and USB2.0 support so you 
can use modern keyboards and mice, Builtin i915 gfx video, drives any vga 
or better moniter.

Running the same basic install cd you can dl from linuxcnc.org, but will 
need a considerable net connection time once installed to bring that up to 
date.

This motherboard/chipset combo has the lowest IRQ latencies we have ever 
measured and is capable of driving the stepper motor that runs the z axis, 
the carriage on my toy lathe, whose drive is set to microstep the motor by 
controlling the currents in the coils so as to divide each fill 1.8 degree 
step into 1/8, and can do it finer that that in the driver I use, at 60" a 
minute, so it covers the 12" or so of way in just a few seconds.

Some, using it totally dedicated so a lot of the normal background stuff 
is not running have pushed the loop speed down to 20 u-seconds.  I run my 
4 axis mill at about 27 microseconds, leaving it plenty of time to keep up 
with an IRC client, or browse the web in case I need to look something up 
with firefox.  All while the milling machine is making something to an 
accuracy of .0005" or better.  Both machine now have ball screws driving 
them except for Z on the mill, but thats a nook screw, double nutted so I 
can get backlash down to sub .001" accuracy at the screw but lose some in 
the head sled.  But I lengthened its "wheelbase" a year ago and that is 
much better now.

But I have to admit George has done some amazing stuff with his coco's 
using interfaces he built, he has sent me pix of a small steam engine he 
was making with his coco and a home made milling machine with a dremel for 
a spindle.  But it took a lot more time to do it than what I described 
above would take.  That slow is probably good because the dremel spindle 
blows in the wind like a willow tree when pushed.

Huge snip, I'm too windy already.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
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-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS