Hello, I had the unfortunate task of repairing paper shredders for a number of years. What you describe is an infrared detector pair. One led is an infrared emitter and the other is a photo transistor detector. The paper going through the machine provides a reflective surface (white paper is about 80% reflective) and the infrared photo transistor detects the reflected infrared that is emitted by the led. You should be able to use any readily available infrared led/photo transistor, assuming it will fit. The infrared led may be fed directly from the power supply (with limiting resistor) assuming it is not "chopped". Jim Albers On Mon, 12 Mar 2001 10:25:34 -0600 rad0 writes: > my shredder jammed and I discovered that the paper detector > had been mangled and broke from its mount. > > This detector seems to be two clear led's fixed in a mount > pointing down form above the paper slot at about a 45 degree > angle, like a 'V' > > Question is, how does this thing work? It looks to me like two > clear led's, how does it detect anything? > > > Thanks... > > one of the led's is broken and I was wondering if I could just > replace it, and have the thing work... > > I don't see how it detects anything. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu