Could something like be useful?
They are about $12 each but operate at 5Mbps so perhaps you could multiplex
some of the signals. There is also an eval kit
uation-and-demonstration-boards-and-kits/787?k=hfbr-1506amz  You can get
10-foot fibre patch cables with SMA terminations to avoid making your own.

> -----Original Message-----
> From: Gene Heskett []
> Sent: Thursday, April 20, 2017 2:51 PM
> To:
> Subject: Re: [Emc-users] Fiber optic control for CNC
> On Thursday 20 April 2017 11:22:03 Todd Zuercher wrote:
> > Fanuc has been using fiber optic connections for more than 30 years.
> > And I work with an old SCM machine with a Num 1040 control that has a
> > bank of fiber optic remote io that is one of the things holding me
> > back from trying to convert it to Linuxcnc.
> >
> This has been a wish of mine for a long time.  We need some cheap stuff
> can be the equ of an opto-isolator, but with a piece of glass or plastic
fiber up
> to several feet long as the optical media between them.
> With power on the rx end, signal losses in the plastic fiber could be
> compensated. I can visualize stepper drivers incorporating it, probably at
> more cost for the pair of fiber sockets than they cost for the full opto-
> isolation BOM right now.
> All we would need would be an HE IR LED with a molded in funnel to guide
> fiber tip to the chip face in the LED.  Some sort of a jacket on the fiber
> prolong its life if rubbing on something, or to prevent optical crosstalk
> be needed. The major design problem AISI is in gripping the fiber to
anchor it
> at both ends, with long term gripping pressure imprinting itself on the
> creating radiation leaks.  Even glass will do that, but usually over time
> that exceed the life of the rest of the machine since technically, glass
is a
> super-cooled liquid, flowing visibly over the lifetime of the observer.
> The led makers have now had 40+ years to design such a package, and I fail
> understand why it has not happened.
> Or has it, and I missed the announcement?  Thats a plausible excuse given
> age and retired status. If anybody would have it on this side of the pond,
> digikey, and I've only found one candidate so far. Intended to be a
> indicator, the led is conventional shaped, available in several colors.
> starts at $2.15 with a 6" light pipe, Available up to 3940" long. :) With
the far
> end of that pipe facing into an avalanche mode transistor, mounted exactly
> the same as the led, and substituted for the BOM that puts the
> into the stepper drivers input circuits, it ought to be essentially free!
> sort of speed would have TBD.  But I'd certainly have to think its faster
> the 200 to 300 kilohertz we can now drive a $35 M542 stepper driver.
> Look at <>
> And see what you think of it.
> One of those in red led, looking at one of these:
> <>
> Would I think, be a good test bed. Need some smd bypassing of the rx
> and I'm not sure what buffering might be needed to make it actually drive
> opto's in the stepper driver.  Pulse time distortions are quite small and
> data rate can be as high as 16 megabaud.
> Now if I can find where to source the fiber cable it uses in say 10'
> pieces, I could try it out in this lathe conversion. With 10 40"
> assemblies, I could put feet and sheet metal between the pi-7i90 and the
> noise makers already installed.  With 30 of them I could replace the
> leaving the pi's box, except for the power cord, with fiber, and enjoy the
> peace and quiet.
> And I've got Dennis Strander at DigiKey furiously sending out requests for
> more info. W/O the fibers, we're under a $5 bill a connection so far. I
can live
> with that.  We'll see what falls out of my email box in the next few
> > ----- Original Message -----
> > From: "Gregg Eshelman" <>
> > To: "Enhanced Machine Controller (EMC)"
> > <> Sent: Thursday, April 20, 2017
> > 4:39:08 AM
> > Subject: [Emc-users] Fiber optic control for CNC
> >
> > Looks interesting. Can't have a ground loop when there's no wires.
> >
> >
> > ----------------------------------------------------------------------
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> >
> > ----------------------------------------------------------------------
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> >
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <>
> Check out the vibrant tech community on one of the world's most engaging
> tech sites,!
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