Schematics

Discussion in 'The Projects Forum' started by B.A. Klim, Mar 29, 2009.

  1. B.A. Klim

    Thread Starter New Member

    Mar 25, 2009
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    I'm building a flashing LED sign for a hot dog stand vendor. But I'm kinda stumped on how to wire the whole thing up. Is there any good sites on the web to help me figure out the best way to write up a schemtic and wire it properly. Basiclly the sign is designed to have a outer ring that flashes, the inner part to read hot dogs while flashing at a different rate then the outer ring, and a price under the words hot dogs flashing at yet another rate (I was thinking of maybe using 7 segment displays for the price). My plan is to run the whole deal with a basic stamp from parallex. What would be the best way to build this and make it run smoothly?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    Do you want them all to simply flash on and off, or go around like a movie marquee, or different effects?

    A movie marquee effect would be fairly simple.

    What kind of power will the hot dog stand vendor have available? Battery power only, or will they have access to 120vac?
     
  3. HarveyH42

    Active Member

    Jul 22, 2007
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    Define 'flashing'. Do you want them all at once (strobe), or sequentially (marque style)?
    Considerably different circuits. Leds, how many, size (wattage). Probably will need a driver scheme, which will depend on how you define 'flashing'.

    The seven segment price is good, save you from re-wiring every time prices change, which considering the economy and our most generous President, is likely to be often.
    Could use DIP switches to set the segments manually.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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  5. B.A. Klim

    Thread Starter New Member

    Mar 25, 2009
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    Good questions. I guess I forget to mention the power source. Yes, there is going to be 120v used. That's part of the problem is how to run the sign from 120v without shorting any thing out. The boarder lights will be ran in a marque style and the words hot dogs will flash on/off.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    OK, so a power source would be a good thing to start with.

    You can convert an ATX form factor computer power supply to an inexpensive DC supply that would work quite well for your application, and the good thing is that it's cheap.

    Marlin P. Jones & Associates is a supplier who frequently has deals:
    http://www.mpja.com/prodinfo.asp?number=17713+PS
    There's a 450W ATX supply for under $20. Might want to grab a couple of them so you'll have a spare or two. That would power enough LEDs to light up a small town. :eek:

    If you want something smaller, might look at this:
    http://www.mpja.com/prodinfo.asp?number=15900+PS
    $13, 12v out @ 4.6A (you'll need to order a power cord, too). That'll power quite a few LEDs; 225 strings at 20mA per string. You'll need a voltage regulator IC like a 7805 to power the Stamp uC, but that's no big deal.

    Have you decided on what LEDs you want to use for this project?
     
  7. DickCappels

    Moderator

    Aug 21, 2008
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    Yes, use a basic stamp. That way you can tweek it until it works to the customer's satisfaction.
     
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