Circling back to the start of this thread, these guys already did the work. http://hackaday.com/2016/03/20/add-fiber-optic-control-to-your-cnc/ On Sunday, April 23, 2017, 10:06:55 AM MDT, Gene Heskett <ghesk...@shentel.net> wrote:On Sunday 23 April 2017 06:47:12 Gene Heskett wrote:
> On Sunday 23 April 2017 02:03:02 Chris Albertson wrote: > > Gene, > > They do make such devices. But there is one fundamental difference > > between a fiber cable and an isolator, the cable can have any length > > and hence a WIDE range if attenuation. The cable could be short > > and with high quality termination and low losses in the conniptions > > of it could be very long with poorly made terminals > > > > So the transmitter / receiver has to be able to handle a couple > > others of magnitude different attenuation rates. > > > > Look on page 2 of the below linked document The figures describe > > EXACTLY what you are asking for and it even compares it to an > > isolator like you did > > http://media.digikey..../fiber-optic%20devices%20toslink.pdf > > <http://media.digikey.com/pdf/data%20sheets/toshiba%20pdfs/fiber-opt > >ic %20devices%20toslink.pdf> > > I will look when its daylight and I've got a cuppa and one eye open. > > Thanks. Having arrived at a state with a cup of caffeine handy, and at least one eye open at the same time, I see that the toslink stuff @ $2 plus a connector, is rated dc to 15 megabaud, and can handle APF (all plastic fiber) up to 10 meters long. That would work, at a cost per copper wire eliminated in the $5 to $20 range depending on the cost of toslink terminated cables. And that cost rather handily takes it out of the picture when I can buy the non-toslink stuffs at about a buck a wire equ, plus the needed length of APF cable, currently UNK. Cable that when the end has been prepared, is simply pushed into the 20 cent rx or rx terminator over the smd led or phototransistor. > > DIgikey sells the stuff and its cheap because these parts are used > > in consumer electronics and produced by the millions. > > Precisely what I am looking for. Yes, until you throw in the royalties for using the word toslink, which multiplies the cost considerably. Plus that connector is physically large to facilitate gripping it and plugging it in or out, something we would only need to do while troubleshooting. These fibers I have in mind could probably be removed from the connector once it work, and given a thin coat of goop or go2 a quarter inch from the end, inserted back into the connector and forgotten for 20 years, and do it on .2" centers on the interface board. The biggest problem is at the rx end where a good stiff pulldown is needed to drive the opto's in the driver. That may require a booster transistor, depending on the choice of an rx ic. Those I haven't researched extensively yet because I want to call a few fiber vendors tomorrow and get a price on a roll of size matching APF, and what the prep tool costs. I'd love it if the fiber could be directly inserted into a fiber socket in the driver, eliminating another translation in the drivers opto isolators. But thats not going to happen until there is a market for those. And right now, I'm a market sample of one. :( If we could get a maker like Tormach onboard, that might be a big enough niche to fill. [...] 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 <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
