Help - What Arduino buy?

Discussion in 'Embedded Systems and Microcontrollers' started by Darlei, Jun 3, 2014.

  1. Darlei

    Thread Starter New Member

    Jun 3, 2014
    3
    0
    Hello folks,
    Could you give me some help on what to buy Arduino?
    I want to make a LED cube 8x8x8 (or at least try) simple thing hehe
    I took a look in the shop
    http://www.usinainfo.com.br/arduino-original-italia-371
    *
    Ja can tell me if someone already bought and if it is reliable
    Researched in some places and it seems that is, but whatever.
    *
    What Arduino buy?
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    How are you planning on controlling the LEDs? An 8x8x8 LED cube will require 72 outputs. The Arduino Mega 2560, which is one of the largest, only has 70 outputs.

    A search on the Arduino forum indicates that it is possible using shift registers. Disclosure: I have never used shift registers.

    Take a look at this link and see if it makes any sense.

    The limitation is dependent on the number of pins that can be controlled by each model. A 2560 can handle up to a 7x7x7 cube without extra circuitry. It's when you go to eight on a side that you run into complexities.
     
    Last edited: Jun 3, 2014
  3. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    You can drive an 8x8x8 LED cube using the Uno with either shift registers or multiplexers. The Uno is a good all-around board that will work for all sorts of projects. You can't go wrong buying an Uno Rev. 3.
     
    djsfantasi likes this.
  4. Fibonacci

    New Member

    May 23, 2014
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    You can use an Arduino UNO; use the MAX7219 for control up to 64 LEDs, you will need 8 ICs and a lot of items. See the site http://www.instructables.com/id/Led-Cube-8x8x8/, to have an idea.
     
  5. pwdixon

    Member

    Oct 11, 2012
    488
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    Charlieplexing would suggest a good deal less pins are required (24 pins I think) and I think I saw somewhere that that is what people often use when they make 'cubes'. The problem does then come down to how fast updates can be made in order to eliminate visible flickering. Now there are fast Arduino boards using 32bit processors it might be easy but I haven't done the calculations.
     
  6. Darlei

    Thread Starter New Member

    Jun 3, 2014
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    How am getting, could you recommend any simpler design, which does not involve multiplexing?
     
  7. pwdixon

    Member

    Oct 11, 2012
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    Use two large Arduino boards and drive every LED individually.
     
  8. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Charlieplexing gives;
    LEDs = n*(n-1)
    where n is the number of pins.

    The number of LEDs is 8*8*8 = 512

    so you need 24 driver pins;
    552 = 24*23

    the big problem will be the duty cycle which is 1/512, so the LEDs will be very dim, and the refresh rate which is also 1/512 so to avoid visible flicker you need to multiplex at about 50 times faster than that, or 512*50 = 25600 Hz.

    Then you get the other BIG problem; how to wire up 512 LEDs to 24 pins, and how to convert fast moving 8*8*8 patterns into a 24 pin format... Ouch.
     
    Last edited: Jun 5, 2014
  9. BobTPH

    Active Member

    Jun 5, 2013
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    Two simpler designs that do not use charlieplexing were already mentioned: shift register and MAX7219.

    Bob
     
  10. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Oh I agree! Charlieplexing sould be an insane way to try and do it.

    The wiring and construction issues alone would dictate using a 8x8x8 matrix system of some type. :)
     
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