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LED cube — Parallax Forums

LED cube

CardboardGuruCardboardGuru Posts: 443
edited 2007-09-07 18:57 in Propeller 1
I don't know what microcontroller they used for this LED cube project, but it's very doable with a propeller.

uk.youtube.com/watch?v=lFDcdN47V5s

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Comments

  • Beau SchwabeBeau Schwabe Posts: 6,559
    edited 2007-09-07 18:04
    With 6 level's that would make a cool LED clock.



    P.S. I believe that Bre meant a 470 Ohm resistor rather than a 47 Ohm resistor.

    470 Ohms (Yellow, Purple, Brown)·sounds about right if you are using a 5V supply and the LED's are roughly 7mA

    ...use a 220 Ohm resistor (Red, Red, Brown) if you are driving this from a 3.3V Propeller.





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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.

    Post Edited (Beau Schwabe (Parallax)) : 9/7/2007 7:16:53 PM GMT
  • Graham StablerGraham Stabler Posts: 2,507
    edited 2007-09-07 18:22
    There was talk about a different kind of multiplexing (called someonesname-plexing) a few weeks ago that would allow many more leds than the expected to be lit from a given number of outputs, considering that the propeller has 32 IO you could make a seriously cool cube and have leds chasing each other around like flies. I'd use smt leds glued to mylar sheets and connected up with super fine magnet wire, mount in a frame and "jobs a good un"

    Graham
  • Graham StablerGraham Stabler Posts: 2,507
    edited 2007-09-07 18:27
    It was charlieplexing and allows n^2-n leds to be controlled so thats 992 just short of a 10X10 cube. Not quite as good as I imagined (forgot about the cube bit!)

    Graham
  • Beau SchwabeBeau Schwabe Posts: 6,559
    edited 2007-09-07 18:34
    I don't know if it's "charlieplexing" (...I'd never hear that term before this forum) or what, but if you implemented polarity reversal rather than just HIGH/LOW to control the LED's, you can effectively double the amount of LED's you could control·with the same·number of I/O lines you would use otherwise.

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • Graham StablerGraham Stabler Posts: 2,507
    edited 2007-09-07 18:38
    Its this:

    www.maxim-ic.com/appnotes.cfm/appnote_number/1880
  • Beau SchwabeBeau Schwabe Posts: 6,559
    edited 2007-09-07 18:51
    Yeah ok...

    This scheme must be driven with open collector·HIGH for each segment, and then driven·LOW for the Common Cathode (CC)·character of interest in order for it to work properly.



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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • Harrison.Harrison. Posts: 484
    edited 2007-09-07 18:57
    The processor is an Atmel ATtiny2313. The minipov kit schematics are at: http://www.ladyada.net/make/minipov2/hardware.html .

    Post Edited (Harrison.) : 9/7/2007 7:32:21 PM GMT
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