led display

Discussion in 'The Projects Forum' started by ducky_bass, Nov 27, 2010.

  1. ducky_bass

    Thread Starter New Member

    Apr 12, 2010
    Hi, I'm working on a project for somebody's birthday. It's a flashing led display that reads somebody's name, but I'm kind of stuck. I need a fairly cheap way of mounting about a hundred leds in paralell on a perf board, or maybe even a homemade pcb. Any help that anyone has to offer would be greatly appreciated. Thanks in advance,

  2. Audioguru

    AAC Fanatic!

    Dec 20, 2007
    LEDs are never connected in parallel unless they are all measured then sorted into groups that have exactly the same forward voltage. Each group will have a voltage that is different from other groups so the groups can also not be connected in parallel.

    Instead, connect a few LEDs in series and in series with a current-limiting resistor. In series the current is the same in each LED. In series, the supply voltage must be high enough.

    A few years ago, kids wore huge belt buckles with a scrolling bright blue display showing a sentence that was usually cursing. They keyed in whatever they wanted to say.
  3. bertus


    Apr 5, 2008
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    It may be easier/more reliable to have a chinese fab service create the board and populate it with SMD LEDs. You only need connections for row and column, sounds like 10x10 or so?
  5. Wendy


    Mar 24, 2008
    First, start with the LED layout, and the LED color. The color of the LED determines how much voltage it will drop, which affects several other factors.

    Give me a quantity of LEDs and their color and I can help.

    Use a thick piece of cardboard (or plywood) and drill holes just a little smaller than the LEDs. Use a little glue to hold them in place. You can chain them as shown in chapter 1 and two as shown in the article that was referred to you earlier.
  6. retched

    AAC Fanatic!

    Dec 5, 2009
    Im guessing you meant parallel rows rather than parallel-electronically.

    You could use perf board and still use SMD (surface mount) LEDs.

    You can use the next hole over to run a lead to the back side.

    Doesn't seem worth it.

    Have you looked at existing LED Arrays?

    Here is one that you can use with an SPI from a micro