April 2nd, 2008
16×24 RGB LED Matrix
The most significant part used in this project is Texas Instruments’ TLC5940 LED PWM driver. It uses a clocked serial data input, and provides 12 bits of PWM resolution on each of 16 outputs.
Normally, the TLC5940 would require one output for each LED element. Since there are three elements per RGB LED, this would add up very quickly; the planned array would require 3 * 24 or 72 TLC5940 chips.
16×24 RGB LED Matrix: [Via] – [Link]
June 24th, 2008 at 1:06 am
Displays of this size are rarely constantly powered (disregarding the implications of PWM). The LEDs are most likely placed in a matrix similar to that used for reading keyboard input, i.e. the anodes are wired together vertically, the cathodes horizontally, with only one cathode-row being activated at a time. Then only three TLC5940 units (one for each color) would be needed to control the entire display, with the data for each subsequent row being latched into the chips at the same time that the row is activated. If that setup produces too low a refresh rate, then it could be controlled in two 16×12 sections by 6 chips, or three 16×8 sections with 9 chips.
This is the same concept that I’ll be using to build a full color illuminated 8×8 button pad, which would only need two of these chips at minimum, but I’ll likely use three, so that it can be treated electronically as a 16×4 matrix, thus doubling the refresh rate.
June 24th, 2008 at 5:00 am
Oh, I see, that’s really what he plans on doing…
June 24th, 2008 at 2:12 pm
thx Bug, if you would like to share the project on this Blog don’t hesitate to contact me.
July 24th, 2008 at 12:32 pm
hello
nice project !!
I’d like to drive 64 common cathodes RGB leds
I began my project: http://www.julienbayle.net/diy/LiveInterface/
it is a monome clone arduino based and sparkfun PCB based.
could you help me ?