On 04/22/2017 01:01 PM, Gene Heskett wrote: > On Saturday 22 April 2017 14:26:56 Linden wrote: > >> When I worked in the semi con industry we used to have converters for >> regular rs232 serial com at 9200 bod. Was a 9 pin sub d at one end of >> the adaptor then 2 glass fiber cables plugged in to the other. The >> receptacle and the fiber cable were made by omron. I think the device >> itself was made in Austria and grew out of some ones basement to small >> production. The only problems we had were the glass fiber portion of >> the cables not being crossed when some one had it apart or corrosion >> on the little PCB due to exposer to HF fumes and other nasties. This >> was on machines designed and built in the early 90. >> > Gee I wish I could convince folks I do NOT need a serial signal at such > and such a baud rate. ALL I want to do is turn on an led shining into > the fiber at one end, and detect it with a high gain phototransistor at > the other end. Seems pretty simple to me. Turn on the led shining into > the end of the fiber for 3 u-secs, the phototransistor does a turnon at > the other end, and voila! a step pulse, with no noise being shoved into > the circuit on either end. Leave another led turned on for the duration > of the dir signal when I want to reverse the direction. rs-422-485 > gismos I have a bag of 5, still haven't found a place to put them other > than hanging on the end of a usb extension cable as a pretty, lights up > bright red so I can pick my way out of the garage if the overhead > lighting breaker fails. I was going to use one to drive my vfd, till I > found the fake vfd didn't didn't have any seriel circuitry, not even > designed in but un-populated on its boards. A SpinX1 runs it rather > nicely after I programmed it from its own keypad. > >> On April 22, 2017 9:56:27 AM PDT, Gene Heskett <ghesk...@shentel.net> > wrote: >>> On Friday 21 April 2017 19:10:23 dave wrote: >>> >>> Did you get my PM to you yesterday evening? >>> >>>> Years ago when I thought fiber might catch-on I grabbed some >>>> 62.5/120 plenum fiber at Boeing Surplus. >>>> I got as far as connecting a 10-base2 card to a fiber converter >>>> fishing out both ends of the fiber on the reel >>>> and terminating with 3M (?) hot-melt end. It worked nicely but 10 >>>> Mhz isn't straining fiber very much. The good thing about fiber is >>>> the >>> low >>> >>>> error rate; something around 1E-12. I just disposed of the >>>> converters a few days ago. >>>> Still have several Km of fiber and a few connectors. 10-baseT works >>>> just fine thru conduit buried between desktop >>>> (house) and shop. About 35 m. >>>> >>>> Dave >>> I found, at newark/element14, some more fiber fittings, in this case >>> a >>> >>> board mount cover for a 603 sized smd led that the fiber can be >>> plugged >>> >>> into, takes 2mm od fiber, snap fit in board holes, at $0.17 a copy >>> from >>> >>> Bivar. Found some fiber but in 10" lengths, assembled, so still >>> looking. >>> The key brand name seems to be Bivar for the hardware. 603 size smd >>> leds >>> are similarly priced. I did find an smd phototransistor, but its >>> target >>> >>> is not centered in the package. Not a major problem since I'll >>> probably >>> >>> be designing the pcb, but it would be nice to use the same pcb >>> pattern on both ends. Since Bivar has a phone numnber in the pdf, >>> I'll see if I >>> can contact them Monday. Hopefully its still a good number. >>> >>>> On 04/21/2017 01:53 AM, Erik Christiansen wrote: >>>>> On 20.04.17 14:51, Gene Heskett wrote: >>>>>> The led makers have now had 40+ years to design such a package, >>> and >>> >>>>>> I fail to understand why it has not happened. >>>>> Somewhere near the bottom of my junkbox is an envelope with a >>>>> pair of Siemens opto-link (real product name long forgotten) >>>>> devices, which came out around 35 years ago. They're small grey >>>>> rectangles with through-hole pins, and a fibre entry with >>>>> ring-nut (like on a collet holder) on one end. Dunno if they're >>>>> still marketed, though. >>>>> >>>>> At Digi-key, this Broadcom offering looks just like one end: >>> https://www.digikey.com/product-detail/en/broadcom-limited/SP0000638 >>> >>>>> 58/516-2872-ND/2220931 >>>>> >>>>> But that would leave the rest of my coil of shielded twisted-pair >>>>> (for RS485) cable gathering dust. With 7v of permissible >>>>> common-mode, and differential transmission for noise immunity, >>>>> what more is really needed? RS485 transceivers are around $2 to >>>>> $3 IIRC. (I saw some for 25c today, but they were surplus stock >>>>> of a now obsolete device.) >>>>> >>>>> Erik >>> --------------------------------------------------------------------- >>> - >>> >>> Gene, I thought about the limit switch thing years ago. The problem is getting enough energy into a small fiber. 62.5 um is not a large target. However, 900 um fiber if you can find it might be just right. For short runs even plastic fiber should work.
Dave ------------------------------------------------------------------------------ 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
