Just incase you haven't caught the theme here, we are most all saying "this
just isn't going to get done by a hobbyist."

Now, I for one would just love to be proven wrong on this point, so I'm
looking forward to your posting a .jpg of the finished project, but.... just
getting data to the drivers (what ever type you manage to afford buying in
that quantity) in real time is going to be pure hell. You might be able to
get a sequence programmed into individual PICs (each driving a few LEDs) via
a daisy chain serial bus of some sort in a few seconds and then play back
the sequence in real time but moving 100000 bits of data in real-time to
something that big is a challenge. Maybe 8 LED's per PIC (no.. too dim..
need driver) or Latch/driver chip and then all the latch inputs connected to
a 8 bit bus, lets see that's... 12500 PICs or Latches so you will need some
sort of driver for the bus that can put out current for 12500 devices to
accurately and quickly read? How about a hierarchy? What is the "fan out"
for components these days? I've stopped looking as I never seem to connect
more that one or two of anything to any one signal.

I was thinking about a electro-mechanical version of this some time ago,
with big Christmas lights and a drum with metal contacts and brushes turned
by a small motor. Slip different insulating cylinders with patterns cut out
to flash the lights with a message. Very low tech and all kinds of RF
interference from the arcing on the brushes, but it would be an inexpensive
fire hazard.... Disclaimer: I am not advising that anyone build such a
monster as it could be hazardous.

---
James Newton mailto:jamesnewton@geocities.com 1-619-652-0593
http://techref.massmind.org NEW! FINALLY A REAL NAME!
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-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Steven Rightnar
Sent: Tuesday, March 21, 2000 10:26
To: PICLIST@MITVMA.MIT.EDU
Subject: driving 1000's of leds


Hi all:
OK maybe my last post didnt make it or maybe my ?'s were blown off. I
seriously want to build this gaint computer monitor out of three different
colored leds as my pixels. I have seen huge ones biult to cover the streets
in down town Las Vegas of course these are alot bigger than the one I want
to build. So at first sight for 100000 leds I need appprox 10000+ PICs
however since I have not got a clue about how to start this could someone
please direct me... even if it is over a cliff. Thanks (flame me as needed).

Steven