----- Original Message ----- From: "Bob Blick" > Some day I gotta find time to update my webpage, I have lots of tips and > some new ideas. I want to scrap the memory capacitor and setting buttons, > and just have a photodiode near one of the LEDs - just hold your finger > near the digit you want to increment and the timing of the pulse back from > the photodiode is how you detect which one. Of course I need to finish the > code for that too. That sounds pretty cool. I still haven't made my own propeller clock yet. :-( You two guys might be interested in this. I was killing some time inside Spencer Gifts a couple of weeks ago while waiting on my wife to get out of the eye doctors office. In the back of the store where all the black light stuff is, they had an interesting toy. I guess you'd call it kinetic art, but it greatly resembles the propeller clock concept. It's a black spinning disk about 12" or so in diameter. It has 8 or 10 RGB LEDs arranged in a straight line from the center out to the edge. As the disk spins, it creates interesting segmented multi-colored circular patterns. I believe they were US$29.00 (maybe 39.00). What really intrigued me was that every LED was individually addressable. I wanted to buy it just to see how they did their slip ring coupling. I wanted to see if they literally had the 30 odd individual contacts required to do the 10 or so RGB LEDs. After thinking about it for a while with my "how cheaply could an engineer make this" mindset enabled, I figure that they just spin the entire electronics assembly and only transfer power (2 wires) thru the coupling, otherwise the coupling would probably be the most expensive part of the device. It makes nice patterns while still coming up to full speed, so I figure there is probably more than one disk position indicator. I'm thinking a few magnets evenly spaced around the circumference of the disk and a single Hall sensor. Or do you think they just use a single reference point and factor in the acceleration to keep the pattern nice and evenly layed out? After telling my wife all about it, she says I can have one to "tinker with". ;-) I wish to first see how it's constructed and then replace the "brains" of it with something a little more useful, like an analog/digital clock display that also does cute patterns that I like. ;-) -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist