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Light matrix

Discussion in 'LEDs and Optoelectronics' started by wormsas, Oct 3, 2011.

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  1. wormsas

    wormsas

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    Oct 3, 2011
    We are planning to create 20x50 light matrix or maybe bigger(20x50/60/70/80). For light we will use light paper, which powered by 90-130v AC, but every peace has converter 12V DC to 90-130V AC. So i think it will be better choice to create all controlling with couple high power converters from 220V AC to 90-130V AC. I have one idea to use dmx, but it's limited to 1024 devices, also if I use this solution I can't create bigger matrix and it's not best choice for matrix controlling. Also if do with this solution I need to connect every light source to main station. Maybe it's easier to create matrix connection, but I don't know what controlling solution to use for this size and power of matrix. Maybe you can help me and offer how to controlling.
     
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    what is "light paper" ? cant find any reference to it on google

    Dave
     
  3. Resqueline

    Resqueline

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    Jul 31, 2009
    It's Electroluminescent technology (EL). It was used in the 60's in the instrument panel & radio of the Dodge Charger. It's sometimes also used for backlighting LCD's.
    It's basically a layer of some kind of salt between two conductive layers (one transparent). It requires a relatively high AC voltage to light. They come in different colors.
     
  4. poor mystic

    poor mystic

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    Apr 8, 2011
    Last edited: Oct 4, 2011
  5. wormsas

    wormsas

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    Oct 3, 2011
    More technical info about EL is here: http://glowhut.com/a4-size-electroluminescent-panel-with-el-inverter-and-ac-adapte4.html

    The main thing is, that I know how to create LED matrix, but how to create matrix from this elements, I don't have idea. Maybe create same scheme that is using in LED matrixes, just use optrones for controlling needed electricity. But i don't know is it really work and maybe it's easier solution.
    Also best solution will be use couple powerful transformators and frequency changers and when control everything with changed electricity.
     
  6. poor mystic

    poor mystic

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    Apr 8, 2011
    :)
    So let me be sure I have the question right... Do you plan to create a matrix of A4 electroluminescent panels? How many panels do you plan to use? (Wow!!)
    Or, do you plan to use smaller panels?

    In either case, you're going to need to switch 100VAC power. Not too hard on the face of it, but how fast do you want the switching to be? Do you want to show moving images? How fast are the images moving or changing?
    Sorry to complicate the question.

    I should think that triacs would be capable of the job, in the best case. Triacs can switch AC and will automatically switch themselves off at voltage reversal.
    Depending on how much current is involved, it might even be possible to use one of the Motorola opto-isolated triac drivers directly without the need for an external device. (This is very doubtful but if the panels are small it might be a go .)

    So. Information, information, information. This forum eats information!
     
  7. wormsas

    wormsas

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    Oct 3, 2011
    Yes, I am planning use maybe not A4, but A6 panels. About 20 x 50 (maybe 70) pieces.

    Yes, it will be good to show images, but simple, because resolution it's to small to show something more detailed. How fast it could be it's hard to calculate. For example to show moving text or moving sound wave, not real time, but that it will be nice to see it. I think 4-5 times per second it will be not bad result for turning on and off for one peace.

    The idea, create big matrix for stacionary outdoor use. The primary idea is, taht one pixel has to be about A6 paper size. Maybe You have better ideas what use for light source, that it will be quite cheap.
     
  8. poor mystic

    poor mystic

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    Apr 8, 2011
    :)
    I'm not sure what you mean here. 20 x 50 actually means 1000. and that is the correct figure... in order to get 20 x 50 resolution you really need 1000 pieces. Modern displays use much higher resolution so that millions of picture elements are required in the displays.
    As for alternative display technologies, there must be billions of dollars poured into reaearch annually. But don't let that stop you... the least you can achieve is a better understanding of the problems and you'll be learning the whole way.
    My boss of 30 years ago wanted to use fluorescent crystals which he envisaged being excited by a scanning ultraviolet laser. Wooh! Danger, danger! He wanted to make huge displays using that technology. Probably not impossible...
     
  9. wormsas

    wormsas

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    0
    Oct 3, 2011
    Yes, I known that for high resolution it is needed millions of pixels, but for this matrix I don't need high resolution, because, as I mention, on this "display" will be show text, equalizer and similar simple elements.

    One EL need AC120V 700Hz-1000Hz power (~18A). And the main question is how I can control matrix from 1000 elements. I have idea to use couple transformers and frequency changers to get needed power, but what scheme can control this. Maybe I can install moc's and Triac in this scheme (red circle) - http://imageshack.us/photo/my-images/32/1301433n.png/ and when change leds with EL elements and control everyone element separately?

    So questions:
    Is this scheme will work as I thinking?
    Is is possible to buy transformer /frequency changer with this parameters: AC220C 50Hz to AC110V 700Hz-1000Hz, 5kW or more?
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,490
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    Jan 21, 2010
    there are many ways...

    1) build a matrix and scan it row by row.
    2) charlieplexing
    3) use shift registers and latches.

    These are listed in order of needing most pins to least. The last one requires 3 pins to drive an almost unlimited number of outputs.

    I'd go the latter route for anything not easily multiplexed. It has the advantage of not causing blinking of the display at high frequency, and this may be an advantage when using something (light paper?) that either has a slow response, or cannot be safely used with high current pulses.

    Check out the datasheets for the 75HC595. If you're using an arduino to control them, you can clock out the data for 1000 panels in a millisecond or so if you use the right method -- or so I'm lead to believe. If you use bit banging it will be much slower.

    You would need to interface the 5V signal to a high voltage controller, and do it perhaps 1000 times. This is where the question of economy of pins vs economy of other hardware comes into play very significantly.
     
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