The Ontario Science Center in Toronto has just such a display. You just shake your head from side to side while looking at it to read the message. Bob Ammerman RAm Systems ----- Original Message ----- From: "Jinx" To: Sent: Sunday, May 23, 2004 6:07 AM Subject: Re: [PIC:] Single Row of LED's Illusion - How they do that? > > To be more specific, I had the idea of seeing if it would work with > > just a row of lights in one place and you have to move your head > > to read it > > I don't think so, unless you have more eyes than a spider and you > can select which one(s) is looking at the LEDs > > The effect is similar to how a dot matrix print-head makes characters > with a line of pins. Where the pins struck the paper and made a mark > is the record of where they were. LEDs "print heads" use the principle > of persistence of vision, like a film strip or flip-book. Each frame is a > single static picture but run quickly in succession gives the impression > of a dynamic display > > Bob Blick's Propellor Clock is a good place to start > > http://www.bobblick.com/techref/projects/propclock/propclock.html > > Google for "propellor clock" to get other examples, or eg "message > wand" > > http://www.salient.com.au/led_MessBar.htm > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.