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100 LED Display - Please help, my job depends on it!!

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by leo.j.arnold, Sep 7, 2009.

  1. leo.j.arnold

    leo.j.arnold New Member

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    Hi guys,

    Thanks for all your posts! I've made some progress in the past few days...as I work for a department of a university I got in contact with two electronics lecturers who have been helping me. They have written a PIC program and decided the best solution would be to have 10 PICs controlling the LEDs. With every press of the button the next output of the PIC goes high, when the 10th output is reached every press of the button flashes the 11th output high which is linked to the next PIC in the chain. I am using 10mA high efficiency LEDs with 470ohm resistors, hopefully the PICs will be able to handle having 10 on at once, going to do some testing next week when it is assembled to see if heat sinks are required on the chips. I've got hold of a 5V 2A power supply which should do the job ok.

    Also the lecturers have access to PCB making facilities so they've also designed me a board for the PICs. It's still going to be close in terms of hitting the deadline, can see a few late nights coming my way and my weekend will be spent soldering LEDs...

    Will post some pictures of the finished thing when it's done next week!! Gotta say that I really like the plastic tube and marbles idea, wish I'd thought of that a week ago!! One of my other ideas pitched to my boss was a Connect 4 style thermometer made out of clear perspex, but clearly that wasn't exciting enough for him.

    Thanks again!

    Leo
     
  2. MrDEB

    MrDEB Active Member

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    10 pic's, you going to the moon!??

    ten pics sounds like overkil.
    IMO as weak as it is (a newbi at pic programming, I can't see ten pics!
    if using ttl then yes ten ics+
    1 pic and couple of gates maybe
     
  3. Mr RB

    Mr RB Well-Known Member

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    Hahaha I think I wet meself!

    2 uni lecturers + 10 PICs = 100 LED device :D
     
  4. dave

    Dave New Member

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  5. blueroomelectronics

    blueroomelectronics Well-Known Member

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    How many University Professors does it take to screw in a lightbulb...
     
  6. Boncuk

    Boncuk New Member

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    Exactly 40. :)

    39 to lift and turn the one to screw in the lightbulb. :D
     
  7. colin55

    colin55 Well-Known Member

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    And now you will understand why I will never employ a University-trained person again.

    One screwed me over by walking out after half-finishing his first project, the second said: “Oh, I don’t do soldering,” and the third I can’t remember. None of them had the slightest idea of designing something economical or efficient and they took ages to do the slightest amount of work.

    Getting 10 PIC’s to do the job, when I said you only need to put 3 in series and jumper them from behind. Cut the jumper to illuminate each LED as necessary.
    Or even put a 5 cent slide-switch across each LED.
     
  8. leo.j.arnold

    leo.j.arnold New Member

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    Yes that's a simple solution but hardly the most user friendly, the people who will be operating it are office and admin staff, hardly likely to have a pair of wire snippers lying around. If it doesn't have a big shiny button on the front that says 'press' they won't know what to do.

    Also I'm not sure there's any need to criticise the solution the lecturers came up with, I realise there might be several much simpler solutions but this is the one they came up with and have taken their time to help me make.

    I really do appreciate all your posts and advice, but at this stage making generalisations about university lecturers isn't very constructive and seems a bit unecessary.
     
  9. colin55

    colin55 Well-Known Member

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    I think you are in the same boat as all those around you.
    You don't read or understand what you are doing.
    I also said a 5 cent switch can be placed across each LED.
    What an absolute absurdity to use 10 PIC chips to drive 100 LEDs.
    My staff were all embarrassed at the suggestion.
    It is obvious you have too much spare time on your hands.
    The other poster got it right. How many lecturers does it take to screw in a light? They will all come to watch because they have nothing else to do.
     
  10. Pommie

    Pommie Well-Known Member Most Helpful Member

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    I have to agree with Colin. The 10 pic solution is absurd. It's like turning a pic into a 4017! My initial thought is a 16F887 driving a 10x10 array with low side drivers. If it's not bright enough then add a high side chip.

    Mike.
     
  11. colin55

    colin55 Well-Known Member

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    What particularly annoys me is this:
    We go to all the work of suggesting an answer to a problem for these individuals, and they go away and thumb their noses at as and carry out some absurd solution. If one of my staff came the next day and said “Colin: My mother doesn’t think you know what you are talking about and she suggests I do it THIS WAY,” he wouldn’t see another minute’s employment.
    We are wasting so much time on this forum; helping people that don’t really want to be helped – that’s because it is FREE! And no-one respects you when you don’t charge.
     
  12. Pommie

    Pommie Well-Known Member Most Helpful Member

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    To be fair to the OP, at his/her age I would have taken the advice of my teacher/lecturer over someone I don't know on the internet. Actually, when I was his/her age the internet didn't exist.:eek:

    Mike.
     
  13. leo.j.arnold

    leo.j.arnold New Member

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    I really think that is unfair and a little childish. At no point have I 'thumbed my nose' at you, I explained that I had decided to go with a different solution to the one you had suggested, however absurd it may be, and because I didn't use YOUR solution you've thrown your toys out of the pram like a little kid and gone on the offensive.

    When I made my original post I was really pleasantly surprised at the speed and number of responses from people, and I believe I have said thank you several times to those people. It is a shame that one person's seemingly narcissistic personality disorder has tainted this experience.

    If you feel you are wasting time on this forum by answering questions from 'people that don't really want to be helped' I suggest you don't post again until you can accept that people aren't going to take your solution as gospel and might just possibly choose a different route.

    Thank you to everyone else who have managed to hold their tongue at my apparent absurd use of 10 PICs, it is a solution to a problem, it works, it might not be the most efficient way of doing things, but it achieves the end result.

    Now back to soldering those LEDs...
     
  14. zorbzz

    zorbzz Member

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    I think that Your initial post should have just asked for someone to design and make your sales indication chart for you. You have obviously chosen the "least work for you" path but wastefull to make approach, which you really should have let people know about before posting here.

    From my experience on this board, people are very helpfull and genuinely out to help others that have an honest interest in electronics but also find it hard to comprehend someone doing what you have done with the 10 PIC design choice when to them that is seriously wastefull for anyone that has the ability to design their own products and ideas to go forward with, which they have spent time advising you on.

    It also seems to me like you are getting a bit more arrogant towards these responses because you have finally found someone to do your work for you.

    You shouldnt do that.
     
    Last edited: Sep 13, 2009
  15. MrDEB

    MrDEB Active Member

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    Soldering LEDs!!

    what happened to the 20 led bargraph displays idea.
    would save a-lot of work seeing how your going to be soldering all night long all them pics.
    just the soldering alone will take 10+ hours (my guessmate)then assembling the tower, testing then debuging.
    What series pics are the lectures suggesting??
    be interested in seeing there code and wiring diagram.
     
  16. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Bargraph displays are cool but only 0.1" tall LEDs. If the display is 10" tall they're perfect.
     
    Last edited: Sep 13, 2009
  17. MrDEB

    MrDEB Active Member

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    Could use two bars per

    the 20 segment bargraphs are just under 10" but using two bargraphs would make it 20" tall.
    using a 4017 to multiplex the LEDs and your done.
    My concern is all that soldering and all them pics.
    I hate to say it but I question if it will be done on time.
    Hopefully it will
    I like the idea on a 10x10 matrix wiring scheem.
    just one pic, some resistor arrays, multiplex the arrats and your done
    nothing complicated.
    just program the pic to count from 1 to 100
    have the outputs all low until you need to start counting.
    really curious as to what the lectures come up with as far as code.
     
  18. colin55

    colin55 Well-Known Member

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    You really can't produce a 10 x 10 multiplex with a PIC chip without a lot of drivers.
    And personally I think all advisers to this column have "been smacked in the face" by you accepting to carry out the task with 10 PIC chips. Let me see if ONE of the advisers will EVER accept your attitude or approach to this problem.
    Let me see if anyone will ever advise you again.

    Colin Mitchell.
     
  19. MrDEB

    MrDEB Active Member

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    a little harsh Colin55 but I kinda have to agree.
    10 pics is way overkill and as far as I can tell the op didn't take any of the quality suggestions offered.
    tried to make the project easy and i looks like it turned into a convulated nightmare.
    come time to debug--have fun
     
  20. Mr RB

    Mr RB Well-Known Member

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    I apologise leo.j.arnold. My post may have sparked a backlash of anti-uni comments (or anti-overkill comments??) or maybe people were all going to tease you anyway... but it was not my intention to insult anyone or to say anything negative other than I was trying just to poke a little friendly fun at Uni lecturers who can often be a little gung-ho throwing tons of parts at a design because they never have to pay for any parts...

    I am curious to know whether your 2 lecturers actually BUY their PIC chips or if they just email Microchip and request another 100 "samples" for "university research". I have to buy mine... :(

    I feel the same as MrDEB re wanting to see the solution. It would be great to see the final design you came up with, with schematics/code etc when it is completed. It would be a shame to let this end on a negative note when some many people tried to help you and showed an interest in your project.
     
  21. blueroomelectronics

    blueroomelectronics Well-Known Member

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    I wonder what the OP's "job" is?
     

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