LED matrix with a gross of pixels

This LED matrix is arranged in a 24×6 pattern for message scrolling. There’s no etched boards here, making us wonder where [Syst3mX] found protoboard this long. He’s using an Arduino to drive the demonstration (clip after the break) but you can use any microcontroller with this setup. That’s because he’s using three shift registers for column data and a decade counter for row scanning, requiring just five control pins.

While you’re going to the trouble of ordering components, maybe you should try your hand at building a touch sensitive LED matrix too.

Comments

  1. Sweet I want one!

  2. jeff-o says:

    Oh, you can buy 12×12 sheets of perfboard pretty easily. Usually you can find it where the plain copper clad boards are sold.

  3. Brennan says:

    Pretty sweet, the LED’s look damn bright in the video.

  4. John says:

    and the source file is….chan chan chan chan…where????

  5. Rockrat says:

    This is relevant to my interests. I write software (Flex, AS, AIR) and just got my first Arduino board. I am wanting to learn how to make a simple countdown timer using the arduino to power a 7 segment led matrix. Does anyone know of a good starting point?

  6. Entropia says:

    Some students at my uni made a LED scroller or discrete LEDs. Standard 5 mm LEDs, and the board has about one meter long in real life, with character height about 10 centimeters. I never saw the actual construction because the LEDs are behind a smoked persplex glass but that must hundreds of LEDs!

  7. Tom says:

    @ Entropia – Thousands… About 4 thousand I’d say from your description : op

    Re: Long Perfboard, check Farnell, Roth Elektronik make some pretty (relatively) massive peices:

    100mm * 580mm(!)

    http://uk.farnell.com/roth-elektronik/re210-s3/pcb-prototype-re210-s3/dp/1221151

  8. zerth says:

    @rockrat

    http://www.hacktronics.com/Tutorials/arduino-and-7-segment-led.html

    That’s for a common anode 7-seg, if you have a common cathode, it’ll be different.

    You might want to get some shift registers if you don’t want it to take up half your pins.

    http://www.arduino.cc/en/Tutorial/ShiftOut

  9. Jac Goudsmit says:

    I’m thinking with a little tinkering this could be changed into a cheap system to control a huge block-controlled model train track with little hardware and little wiring.

    Think “10 speeds” instead of “10 LEDs per column” and think “24 blocks of track” instead of “24 columns”.

    Hmmm…

  10. DanG says:

    On a related note, I stumbled across an interesting technique for dimming LEDs called Bit Angle Modulation.

    This technique works very well for controlling large LED Matrices because you only have update the LEDs once per bit of brightness resolution. IE, for 16 shades of brightness, you only have to update the LEDs 4 X refresh rate times.

    http://www.batsocks.co.uk/readme/art_bcm_3.htm

  11. D_ says:
  12. walt says:

    allow me to save you the trouble of finding out (the hard way) what happens if you actually click the link.

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  13. Vadim says:

    You don’t need to be a pro member, you can just sign up for free and get the source code

  14. osgeld says:

    yea fill out a username and password bam you can see full articles

    if that is too much for you then do you really need to be attempting to make anything?

  15. cgmark says:

    @rockrat
    While you can drive LED directly from the arduino like in this article it really isn’t the most practical/easy way to do it.

    There are LED driver IC that require only a few pins on the arduino and will control hundreds of LED just by sending the chip the correct commands.

    For standard digital display

    http://www.maxim-ic.com/datasheet/index.mvp/id/1339

    This one does text and has 104 ASCII letters ready to use.

    http://www.maxim-ic.com/datasheet/index.mvp/id/3379

  16. Rockrat says:

    @cgmark

    I had purchased the MAX7221 or its variant a while back to implement this, but I got stuck trying to figure out how to hook it up to the arduino. I know I need to use the arduino’s serial outs, but I didn’t know which pins went to which on the chip. I think I have the software figured out, but is it possible to consistently give commands via the usb (like ever 500 milliseconds) to update the display or is this writing to many times to the arduino?

  17. Brennan says:

    Can someone explain to me why using a 4017 counter chip is a better solution than just using 6 output pins on the Arduino? If you still have to manually send a pulse to the 4017 to scan the rows there doesn’t seem to be any advantage except for freeing up 4 output pins on the micro. I suppose it would make the software a tiny bit easier/faster to send 1 pulse to the 4017 rather than controlling the state of 6 output pins, but is that the only reason?

  18. TiredJuan says:

    @Brennan: Yeah, it’s used to free up pins. (perhaps for sensors or more shift registers etc)

  19. George Johnson says:

    Vector makes the best pad per hole boards, some quite long too

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