Gene, You might find it useful look at how industrial sensors do this. I use a lot of Automation Direct fiber prox sensors. They have both thru-beam and diffuse reflective types. In any case, they always have lenses on the ends of the fibers.
https://www.automationdirect.com/adc/Shopping/Catalog/Sensors_-z-_Encoders/Fiber_Optic_Sensors/SSF_Fiber_Sensors They have a couple of different sensor heads. For reflective applications, I prefer the devices with programmable threshold and gain. Non-adjustable ones are ok for thru-beam. It may be possible to use consumer optical link parts to replicate these sensors, but not as simple as it first appears. The key is focusing the light at the fiber end. You might try a $2 laser pointer module for the transmitter side to see if coherent light will reduce the need for a lens. It may lose its coherence in the fiber though. -- Ralph On Apr 22, 2017 6:25 PM, Gene Heskett <[email protected]> wrote: On Saturday 22 April 2017 20:03:05 dave wrote: > 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 This stuff I'm looking at is plastic, a 1.2mm core with a 2.0mm jacket. Plastic of course. The longest run would in the 16 feet range. Step-dir lines to the drivers maybe 40". At the response times I'd expect, losses should not be that bad even in plastic. I watched the local cable folks install a fiber link from our studio output to the cable head end in Enterprise WV, 39 klicks long as the cable went. This was in about 1998. Had to send the splicer back and get new knives or something in it, but when it came back, the first cut & termination they did was good. 0.47 db of loss in that 39 klicks of fiber. I half expected 15 to 20 db of loss. Blew me away. I probably failed but tried not to look impressed. 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 [email protected] 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
