Ben Hencke > On May 23, 2004, at 9:51 AM, Dave Tweed wrote: > > 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! > > That wouldn't be the iBall+? > http://www.spacewriter.com/ No, that's a competing product. Ours is much larger. > I can't imagine that using anything as powerful as a dsPic, maybe > memory + controller. There are a couple of reasons for using a dsPIC, including the very high instruction rate, and the single-cycle multiply comes in handy for things like the servo algorithm that keeps the raster spacing locked to the period of the rotation. Also, we use scalable vector fonts that are rendered in the ball itself, which requires a significant amount of computing horsepower. > Unfortunately it is stuck with 3 bit color. Red, Yellow, Green, etc but > no orange, etc. Only on/off for each r/g/b element. We currently have 6-bit color, with the possibility of going much higher if we develop a custom LED driver chip. > What is the deal with these eye/i ball copycats? Are there patenting > issues with mechanically scanned displays? Some aspects are patentable, but the general idea really is quite old. Most of the competing products we have evaluated fell way short of ours in the area of long-term reliability. Ken Pergola wrote: > I remember seeing one of these projects at the Circuit Cellar office in > Vernon CT around 1994/1995. Ken Davidson showed it to me. I was a bit > embarrassed in that I really had to work at it to see it, but I guess it > varies with people. Did you see this at Circuit Cellar as well? No, I never saw that one. -- Dave Tweed -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.