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clock7
Joined: 04 Sep 2006
Posts: 6
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 16 Feb 2007 0:58 Components for Outdoor LED Matrix |
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I am making an outdoor LED display system using matrix LEDs. I already have made an indoor system but am not sure if the outdoor system has the same circuitry or not.
Attached is the basic circuit diagram for my indoor LED system, please tell me what components I need to replace to convert this system into an outdoor one. Specifically I want alternatives to the following components in the outdoor system
1. T1: B772 Transistor driving the rows (can it sustain the current requirements of the outdoor matrix ?? )
2. Resistors: How will the values of R1,R2 and R3 change??
3. IC1: ULN2003A, do I need a different current sink IC for the outdoor model ??
As you see in the second picture the outdoor matrix I plan to use is also 8x8 (has 4 outdoor LEDs in each pixel). Please tell me the part numbers that I should replace my existing components with. Any help will be appreciated.
Thanks
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batojay
Joined: 15 Oct 2006
Posts: 1
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| 16 Feb 2007 13:07 Components for Outdoor LED Matrix |
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| Clock7, U can try 10 Ohms for R3, all the components are the same. I am not sure about the 5V supply....is it enough to source 4 leds in series or not....just try it first.
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electronics-circuit.com
Joined: 11 Feb 2007
Posts: 4
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| 17 Feb 2007 4:35 Re: Components for Outdoor LED Matrix |
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First All you must check distance between Display and control How long ? Because indoor and outdoor it differrent distance .If DisplayOutdor long distance (about 5-10 M) sure that control Unit must have hight current more than indoor . But if control unit and display close up general we desing by Use RS-232 for Outdoor LED Matrix..
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Go to the future
www.electronics-circuit.com
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kashiffarhan
Joined: 18 Mar 2005
Posts: 5
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| 17 Feb 2007 14:31 Re: Components for Outdoor LED Matrix |
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in your old ckt
( 5v supply - 2v led drop ) / 47 = 64 mA = lED cURRENT
you can increase your current for new outdoor board by decreasing 47
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clock7
Joined: 04 Sep 2006
Posts: 6
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| 17 Feb 2007 15:48 Re: Components for Outdoor LED Matrix |
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ok I will try decreasing 47 to 10 ohms as suggested. Still is the B772 transistor good enough to sustain that kind of load? Each transistor will be responsible for 1 row (96 x 4 LEDS in each row). Or do I need to use some model other than B772?
My 5v power supply is 2amps, I don't know the power rating of the outdoor panel, I hope it would be enough.
Other information
Total Rows: 8 (1 transistor on each row)
Total Columns: 96 (12 outdoor panels used hence 12 x 8 = 96 pixels/row)
Note each pixel has 4 LEDs which means a worst case scenario of 96x4 = 384 LEDs/row. I hope the B772 can handle that and will 2 amp supply be enough? Since only 1 row is on at a time due to multiplexing.
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clock7
Joined: 04 Sep 2006
Posts: 6
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| 20 Feb 2007 19:36 Re: Components for Outdoor LED Matrix |
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| Ok people I tried it with a 10 ohm resistor, but it doesn't work. The large outdoor matrix does not light up (very dimly sometimes). Help?? what components do I replace?? the transistor?? and with what?? each 4x4 cluster in my matrix draws approx 30amps according to the datasheet.
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hid
Joined: 22 Feb 2007
Posts: 12
Helped: 1
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| 27 Feb 2007 1:18 Re: Components for Outdoor LED Matrix |
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I'm sorry, but I think you're in the wrong direction. You shoudn't be trying to use the same hardware, re-start from scratch. For an outdoor display, you should start from the most important components, the leds. Which ones are you planning to use? Are you sure they are bright enough for outdoors, under direct sun light? How are you planning to connect each led from the groups of 4 leds (series, parallel)?.
It would be better not to use multiplexing, use latchs, and drive from a higher voltage supply (10-12V) instead of 5V.
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clock7
Joined: 04 Sep 2006
Posts: 6
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| 07 Mar 2007 20:09 Re: Components for Outdoor LED Matrix |
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The outdoor LED panel I am using right now is a 8x8 square cluster which only supports multiplexing (I can't turn on more than 1 row at a time)
If I am to use an alternative design, I need to know which outdoor LED's I should use which use a non-multiplex design. Can anyone recommend an outdoor panel 8x8 preferably which supports a non-multiplex design ?? Any part number/supplier would be helpful ??
I am attaching pics of the LEDS I am currently using (which only support multiplexing due to thier limited pin numbers at the back). They are 5 sq inches in size I would want an alternative of the same size.
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