Project: Scrolling LED display with out any controllers....

Discussion in 'The Projects Forum' started by RRITESH KAKKAR, Dec 6, 2011.

  1. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
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    Hi again,

    Here, i am posting my few months back project. In this i have used 7 segments to display numerical scrolling messages on it...
    The working of it is very easy, but assembling chip and other good become problem when so many wires came...!!

    12V rectifier, and 555 chip for frequency generation, 4017 decade counters, diode(1N4007 or zener), 7 segment display,etc..........


    [​IMG]



    [​IMG]
    The display is multiplexed 4017 counter ( video of it) is used to scan it while scanning the chip 7447 at right is used for digital outputs for segments.
    This technique was used to display because using couples of chip for all individual display will be costlier and complex.


    [​IMG]

    after the input of 7447 chip that is BCD (8 4 2 1 sequence) was given by setting counters at X and Y axis the bottom one is used for scanning and the Y axis is used to display next numbers ..
    the clock from 555 is divided by 10 many times to slow the frequency ..
    The output of counter 4017 at right ( in a b c...form)are inputted to couple's of AND gates and scanning counter.
    Thus the each output terminal is connected with diode to prevent shorting of signal again..
    The pulse graph speak more than word what really is going on its output terminal.

    The whole circuit of SLD can be sen in Spice.

    here is completed part of it.


     
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  2. T.Jackson

    New Member

    Nov 22, 2011
    328
    14
    WoW this looks excellent.

    I particularly like how neat it is.
     
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  3. Wendy

    Moderator

    Mar 24, 2008
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    Could you post an actual schematic? Without a real schematic this does not qualify for the completed projects, but it very close. I'll let it stay for a while to give you time. Hand drawn and scanned is OK, but the schematic should be complete. Drawing schematics is a necessary skill for anyone who is in engineering or working as a tech.

    The shorthand for the 555, for example, caught my eye. The schematic does not need to be on display full size, and if it is an attachment that is OK. It should be complete enough that someone can duplicate the project if they want (it also goes a long way to answering any questions someone might have).

    Special software formats should be avoided, .gif or .png is preferred. This is so everyone (like me) can view it.
     
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  4. Georacer

    Moderator

    Nov 25, 2009
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    To elaborate a bit more on what Bill said, you should depict the pin numbers of the ICs in all of the wired connections your circuit has. Personally, I have no problem with grouped data wires, like the 7-seg data bus.
     
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  5. Wendy

    Moderator

    Mar 24, 2008
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    Me neither. The ability to duplicate via documentation is what I am after. It is why this particular forum exists.
     
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  6. T.Jackson

    New Member

    Nov 22, 2011
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    I think this could actually be more neat and professional looking rather than functional / useful for something.

    Nice job man!
     
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  7. Wendy

    Moderator

    Mar 24, 2008
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    This is actually a good area for soon to be professionals, just for cases like this. Think of it as free training.
     
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  8. T.Jackson

    New Member

    Nov 22, 2011
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    Well, yes he is already half way there with digital electronics.

    Knowing these waveforms:
    [​IMG]

    Is not easy.

    Reminds me of some old tests that I took in digital 1 and 2. Not many people got high grades for part 2, including myself.
     
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  9. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
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    Hi again,

    I found some more images of it in my hard drives.....
     
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  10. T.Jackson

    New Member

    Nov 22, 2011
    328
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    WoW ur a genius man.
     
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  11. Wendy

    Moderator

    Mar 24, 2008
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    Very good, but I need a schematic, and I have taken over maintaining this forum. Need schematics!
     
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  12. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
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    After all it will take few weeks after finishing my external exam..
    for now LT simulation contain the whole circuit in it..!!
     
  13. Wendy

    Moderator

    Mar 24, 2008
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    Do you know how to screen capture? It doesn't have to be on one sheet of paper either.

    There is a button on your keyboard labeled <Print Scrn>. When you press it the entire screen is copied, and can be pasted into M/S Paint. You can do this to your electronic schematic with your simulator running. From there it can be uploaded to here, though I would crop it first. I mentioned this earlier, but .png is probably the best format to save it in.

    It is a very useful application for many things. Documentation is something you need to learn when you make a project like this, and not just for this site. It is part of the total package of electronics.
     
    Last edited: Dec 7, 2011
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  14. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    oK.........
     
    Last edited: Dec 7, 2011
  15. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
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    OK, here are more schematics.......
    12V supply...

    [​IMG]


    555 astable.....


    [​IMG]
     
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  16. Wendy

    Moderator

    Mar 24, 2008
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    I can hardly wait for the digital electronics. Just curious, did you draw anything for this board before you built it, or were those drawings in the first 3 posts it?

    You mentioned school, I assume you are taking engineering?
     
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  17. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    before it have work on seven segments using 100's of diode (1n4007 than 12V zener as it take less space).....
    here, is my 1st year ELectronic voting machine using diode with display and few counters for counting votes and transistor for switching,etc..
    http://www.youtube.com/watch?v=M9mEMXMPnQU&feature=player_embedded

    all are from here.

     
    Last edited: Dec 8, 2011
  18. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Where??

    yes, of Electrical and electronics.
     
  19. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
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    Completed look of CPU....

    [​IMG]

    Picture of old Zener and simple diode display in school days...
    some of displays are missing too..
     
  20. Wendy

    Moderator

    Mar 24, 2008
    20,765
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    The sticky on the top of the Completed Projects forum spells out what is required for a Project to be displayed on this forum.

    Your project comes close, but does not have everything that is needed. This forum is to allow people to duplicate your work, and is not meant as a forum to show off your work.

    To be acceptable ALL documentation must be hosted by AAC. This includes pictures, schematics, and µC code. Schematics and µC (if applicable) are not optional, they are required. Whether or not you use pictures is up to you, but if you do use photos they must be either an attachment to your post or in our albums. If you do not know how to do this we will assist you (and teach how it is done).

    You Tube videos are acceptable as long as they do not contain vital information. This is the only exception allowed to hosting at AAC.

    You have until New Years Day to correct the deficiencies in the entry. If this is not done the entire thread will be moved into the Projects forum.

    If this happens it can still be fixed. When the Completed Project entry is brought to specification it can be moved back into the Completed Project Forum.

    Thanks for your entry. The moderating staff will work with you to bring it up to snuff. While we are the sole arbiters what is acceptable, we don't want to keep you from showing off your hard work and how you did it!

    This post will be removed once the project is documented properly. Matter of fact, I will remove all posts that aren't directly related to allow you to start fresh.
     
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