It has to be all of those things. First of all, it should be pretty so the instructor/professor will like it and it must be well designed and well executed so that a knowledgeable instructor/professor will like it. Secondly, it has to be affordable by any student. Not every student has the sort of budget that would be demanded by one 8x8 array as you, Erik, have suggested, for every character. Neither would it have been possible for me, though I went to a very much top-flight college, and grad-school, to get the school's machine shop to build me a panel for a project like this, nor would anyone have assigned such a project when I was a student. I was only 14 years old, as a freshman, so the $20 or so per month that I had as surplus were adequate to cover supplies and the occasional printed matter that I required, and the transportation from Andover to Cambridge. However, I couldn't have invested the $4 or so that a case of beer might have cost fifty years ago, (being, then, too young to purchase beer, I wouldn't know).

I'm curious why you're trying to reduce this discussion to little more than another of your food-fights. If you have a clear point, feel free to make it, else please stop trying to force an otherwise general discussion of the issue into your mold.


How many characters? How many words? How large a panel?

Since you've said that all that's needed is four of these 3-cm-wide-and-tall 8x8's I'm curious how you'd illuminate all the words on this apparently about 30 cm x 40 cm panel, or any panel large enough to contain all the needed words. I've already said to Per, I doubt one LED per character is necessary, and that it is probably excessive. He may have an approach that warrants such excess, but you've not indicated how you can take your four 8x8's and illuminate more than, say, six characters with 'em. I'd also be interested to know the benefit of multiplexing LED's in a display that requires individual LED's per character when there are only about forty words that have to be displayed, and many fewer, perhaps a half-dozen, at a time.

The whole charm of this sort of display lies in that the information is codified in words rather than characters. Further it's clear that very few (I'd guess two or, at most, three) LED's per word would be adequate.



Yes the multiplexing is quite straightforward in most cases, but I see no benefit in multiplexing this sort of display. Perhaps you can inform me. Further, perhaps you can provide information about how you will move those four 8x8's around so they cover all the characters without any flicker. What sorts of motors would you use? How would you drive them with enough speed to do the job? Voice coil, perhaps?

RE