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02/16/07 10:44
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#133117 - Components for Outdoor LED Display
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.

My circuit diagram

http://images.elektroda.net/90_1171583565.JPG

The outdoor panel I plan to use

http://images.elektroda.net/62_1171583833.jpg

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 without changing the overall PCB design (yes I want to stick with multiplexing). Any help will be appreciated.

Thanks


List of 43 messages in thread
TopicAuthorDate
Components for Outdoor LED Display            01/01/70 00:00      
   What are the specs?            01/01/70 00:00      
   you are already scewed            01/01/70 00:00      
      any better suggestions?            01/01/70 00:00      
         are your LEDs capable of 200mA ?            01/01/70 00:00      
            Human eye perception            01/01/70 00:00      
               percieved does not matter            01/01/70 00:00      
                  Perception is everything            01/01/70 00:00      
               LEDs are extremely nonlinear, too!            01/01/70 00:00      
                  I covered this            01/01/70 00:00      
                     I wrote -extremely non-linear-...            01/01/70 00:00      
                     that makes no sense            01/01/70 00:00      
                        Example with LTJ-811            01/01/70 00:00      
                           let the sunshine in            01/01/70 00:00      
                              LEDs appear the same in all conditions            01/01/70 00:00      
                                 Err            01/01/70 00:00      
                                    actually we have one multiplexed, however            01/01/70 00:00      
                                    King of LEDS :)            01/01/70 00:00      
                                 mux vs. pulsed            01/01/70 00:00      
                                    better ask ERIK ...            01/01/70 00:00      
                                       well, this is not so 'new'            01/01/70 00:00      
                                       more bright than outdoor....            01/01/70 00:00      
   why I want to multiplex            01/01/70 00:00      
      assumption?            01/01/70 00:00      
         the way multiplexing works            01/01/70 00:00      
            what is required?            01/01/70 00:00      
               Requirements are what you should analyze            01/01/70 00:00      
                  Backwards?            01/01/70 00:00      
                     low-side cap, low-side NPN            01/01/70 00:00      
                        One-bit memory == DC filter ???            01/01/70 00:00      
                           slow decay            01/01/70 00:00      
                              you can have NONE            01/01/70 00:00      
                                 are you sure?            01/01/70 00:00      
                                    yes, I am, yes I have            01/01/70 00:00      
                                 I agree with Erik ... at least somewhat            01/01/70 00:00      
                                    I am still CURIOUS            01/01/70 00:00      
                                       it's like a camera flash            01/01/70 00:00      
      already answered http://www.8052.com/forum/read.ph            01/01/70 00:00      
         Averages            01/01/70 00:00      
   does the A6278 LED driver multiplex too?            01/01/70 00:00      
      if you want to make a nonmultiplexed display...            01/01/70 00:00      
         that clears up a lot            01/01/70 00:00      
            sorry            01/01/70 00:00      

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