Lindy Mayfield wrote: > Hi, I was wondering if anyone knows about or knows of a resource that > explains the logic of how to get the illusion of text by using a single > row of LED's moving back and forth. Yes, there are many variations, generically known as "propeller clocks", although some display information other than time. One example can be found here: http://www.embedinc.com/ourportfolio.asp#eyeball We're currently working on an upgrade for this device that has 96 full-color LEDs in an 18-inch globe. The full raster is 96 x 512 (48K pixels) and looks quite impressive! To put this on-topic, the new unit uses three separate dsPICs (one in the power supply!) and an 18F-something-or-other to handle the external communications. > 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. Yes, it has been done before, as a form of art. A vertical rod with a bunch of LEDs on it sticking up out of a base, sort of like a potted plant. If you stare directly at it, you just see some flickering LEDs. But if you happen to glance past it, an almost-subliminal image gets painted on your retina. It can be quite startling if you're not expecting it. Works best with relatively simple images, not text. To view such displays without shaking your head like a madman, try sticking your finger out at arm's length and look at the tip. As you move your hand back and forth, you'll see the image in the background. -- Dave Tweed -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.