Electronic Scoreboard

Discussion in 'The Projects Forum' started by michaels750, Feb 6, 2012.

  1. michaels750

    Thread Starter New Member

    Feb 6, 2012
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    Hi, I don't no if this is the right thread to post on but i'd like to design and build an electronic Scoreboard counter exactly as the one is displayed in post #7.
    I was wondering if i could be directed to any details on this.

    Any help would be very appreciated.
    Michael
     
  2. Georacer

    Moderator

    Nov 25, 2009
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    michaels750 likes this.
  3. Meixner

    Member

    Sep 26, 2011
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    I can't find post #7, could you link to it.
     
  4. Georacer

    Moderator

    Nov 25, 2009
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  5. crutschow

    Expert

    Mar 14, 2008
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    Are you wanting to build one from scratch?
    What does it need to display?
    How big do you need the digits?
     
  6. elec_mech

    Senior Member

    Nov 12, 2008
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    The OP stated he wants one exactly like post #7, presumably the same size digits and spacing?

    The one in post #7 uses a PIC microcontroller. Are you comfortable programming microcontrollers?

    If not, this could be build without programming using digital logic ICs. Note going this route will require a bigger board, more parts, and more time to assemble. Not a bad thing, but this is something to factor.

    How would you like to proceed:
    1) Microcontroller?
    2) Digital logic?
     
  7. michaels750

    Thread Starter New Member

    Feb 6, 2012
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    Hey thanks for moving to a new thread Georacer.

    First off i'll be using a Microcontroller, what is needed to be displayed is 2 two digit LED displays.
    And yes i'll be building from scratch. If you know what parts i would need to acquire that would be great.
    Example
    [​IMG]
    The size of the chip is not a worry for me. But the size of the LED's are.

    Programming wise i use Picaxe or ezCircuit.
    I'd like it to be able to display scores for two teams.
    The input is either going to be push button or automated.

    The project is in a nut shell is TOP GEAR SOCCER (MINI)
    I'll be building a small field and 4 small remote cars, with goals and the soccer ball being a table tennis ball
    At the present i don't know of a way for the scores to be recorded automatically, but if worst comes to worst i'll settle for a push button system.
     
    Last edited: Feb 7, 2012
  8. elec_mech

    Senior Member

    Nov 12, 2008
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    Okay, so basic requirements:
    -PICAXE
    -Control 2x 2-digit 7-segment displays, approximately 0.56" in height based on the picture
    -Push button or sensor triggered
    -00 to 99 range
    -Presume ability to reset to zero with a push button otherwise cycle power

    I'm a bit rusty in the microcontroller area. If you had more or bigger digits, I might suggest an LED controller IC to use between the LEDs and the uC such as a TLC5940 or similar, but this doesn't warrant it.

    It would require more programming, but you could save on parts by using a multiplex design. That is, you use 7 I/O lines to feed each segment, tie all seven segments together (segment a from all four digits is tied together, all segment b's tied together, and so on), and use four I/O lines to control the ground or Vcc -depending on whether you select comman cathode or comman anode digits - of each digit through a transistor or MOSFET. This appears to be what was done in the picture. If you go this route, look for a multiplexed two-digit display. This will already have the segments tied together with separate ground/Vcc to control each digit and will save you a lot of wiring/routing and time. Something like this: http://www.futurlec.com/LED/7DR5621AS.shtml.

    In essence, you display the value for each digit rapidly. So if you needed to display a score of 01 and 23, you would set all seven segments to display 0, turn on then off the transistor/MOSFET to digit 1 for a fraction of a second, set all segments to display 1, turn on and then off digit two, and so on and repeat. This saves you from needing seven I/Os for each digit (28 altogether) but does require more programming.

    Going this route, you'll need a PICAXE with I/O's for for segments (7), common cathode/anode for each digit (4), switch or sensor input for scoring (2), and optionally a reset button (1). This means you need a PICAXE with a minimum of 7+4+2 (+1) I/Os or 13 (14 with reset). The picture shows a buzzer, so add another I/O for that if you want to add it.

    Be sure the PICAXE pins can supply the needed current to each segment. Typically for such a small display, the current consumption is very low, but do check the PICAXE and seven-segment datasheets to be sure.

    You'll need to program in or use hardware to account for switch debounce if using switches. You could use an IR LED and phototransistor as a beam to detect whenever a goal is made (this is used in air hockey tables) in place of a switch. I assume this is what you mean when you say score automatically.

    Hope this helps.
     
  9. michaels750

    Thread Starter New Member

    Feb 6, 2012
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    Wow, thanks for the information this helps allot.

    I don't plan on having any more digits but if the size where lager and that would save on parts i don't see a down side.

    I'll be getting an 18pin for picaxe so that won't be an issue. Also the push button reset is a great idea.


    I'll get my hands on some IR Led's and some phototransistors to do just that.
    I'm assuming I'll need 2 of each for each goal?
     
  10. elec_mech

    Senior Member

    Nov 12, 2008
    1,513
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    No, this would add a part. You would use the PICAXE to communicate to the TLC5940 through SPI (serial) I believe. This is only helpful if your display draws more current and/or voltage than your PICAXE can provide. You wouldn't need as many I/O lines and could get away with a smaller PICAXE, but this part is $4 or more, so I'd still recommend sticking with the PICAXE alone. A small 0.56" display won't draw much.

    Now, I haven't done this myself, so I'm unsure if you'll need more current than the PICAXE can provide to boost the brightness of the digits, depending on the rate you feed each of the four digits. Powering four digits a quarter of the time (to get power to each digit) vs. all the time may cause the display to appear dim and require a higher current through the LEDs. Just something to keep in mind.

    Just make sure it has a minimum of 11 output pins and 2-4 input pins.

    Depends. You'll need a minimum of one each to make up a sensor pair - one to transmit and one to receive, so two each total, one pair for each goal. This will allow you to make an invisible line that when broken by a passing ball, will act as a switch to increment the digits.

    Now, for an air hockey table, the puck is thin and the goal is thin, so only one pair is needed. If the height of your goal is about the height of your ball, then you only need one sensor pair and place it about halfway off the ground. If your goal height is much taller than your ball, you'll need multiple sensors to detect the ball when it goes in high or low.

    As an example, let's say your goal is 5" tall and your ball is 2" in diameter. If you put one sensor pair on the goal toward the bottom, you'd never detect goals if the ball comes in high and vice versa. So it would be good to use two sensor pairs and place one just shy of two inches off the ground and the other just shy of two inches from the top. I don't know a lot about phototransistors - you may be able to wire them in series so you only need one input for each goal, but you may need an input for each sensor pair, so your goal inputs go from 2 to 4 (or more depending on the number of sensor pairs). Just something to keep in mind.

    Have some heat shrink handy to put on the sides of the IR LED and the phototransistor. It may help concentrate the IR beam a little, but mostly you want to block ambient light from the phototransistor so it is not set off by ambient light, fluorescent bulbs, stray IR remotes, etc.
     
  11. michaels750

    Thread Starter New Member

    Feb 6, 2012
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    0
    I was originally planing on using just a picaxe alone (easier to program).

    Yeah i would like all 4 digits to be bright and visible (just like a air hockey table)
    What could i use to boost the power to meet the required power needs?

    If the goal was to be 5" but i'd think i'll only need one sensor. The ball is unlikely to jump around, plus i'll place the sensor in the middle of the goal and be sure that if the ball went high or low it will always hit the sensor.
    I do have one worry is how will the players get the ball out with out triggering the sensor again, my only idea is not making the goals too deep so that the ball will go in and bounce out (triggering the sensor in the process)

    About that, i was going to use IR to control the 4 mini cars. Am i able to put the IR's on different channels or something to try and avoid this from happening?
     
  12. elec_mech

    Senior Member

    Nov 12, 2008
    1,513
    193
    You could use a ULN2804 or UDN2981/2 depending on whether the 7-segments are CC or CA (common cathode or anode). Put put it between the PICAXE and the 7-segement displays.

    That will work if the ball is just over 2.5" in diameter, but not 2". Just something to keep in mind.

    Excellent point. You could go crazy and add a time delay such that the sensor will not detect a trip (or will ignore any trips) for xx seconds after a goal.

    A lot more info is needed to answer this. Are you going to build the cars or the controls from scratch or use something readily available? If I were doing it, I'd buy ready-made cars with four different frequencies built in such as this:

    http://electronics.mcmelectronics.com/?N=&Ntt=mini+rc+racing+car

    Of course, that may not work for you depending on the size you need and the like.
     
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