Electronics PCB LED Dice Layout

Discussion in 'The Projects Forum' started by Alice., Jan 18, 2012.

  1. Alice.

    Thread Starter New Member

    Jan 18, 2012
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    I'm trying to make the circuit board for the LED Dice as a final project in class.
    http://www.kpsec.freeuk.com/projects/dice.htm
    [​IMG]
    How would I make this schematic on ExpressPCB? I haven't worked with the program before so I don't really get where the trace wires are supposed to go... Are there better diagrams online? Sorry for the vague question... I'm really lost.

    Any general suggestions or tips would be greatly appreciated. Thanks!
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    You got to see behind the PCB :D
     
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  3. Wendy

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    Do you have any basic schematic for this project? If you do post it. I use Express PCB all the time, the reason you need a Express schematic is for a net list, which allows the the Express program to compare the lay out with the schematic as a check. This is very common for almost all PCB programs, Eagle being one of the most common.


    I've got one semi designed, but never integrated it with the 555 timer circuit.

    Rifaa, I think the the OP is needing to design one from scratch as part of a homework assignment.

    Speaking of which, this probably belongs in the homework forum, but I'll leave it here for now.
     
  4. tracecom

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    Apr 16, 2010
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    What type of class is this for and what level of course is it?

    Here is the schematic for the electronic dice project. I simply copied it from the site above. However, I notice that the PCB photo you posted is not from the site you linked to; in fact, it is a differenent circuit and it is from this site. http://talkingelectronics.com/projects/LED-Dice/LED-Dice.html

    Which one are you supposed to use?

    [​IMG]


    If your assignment is to create a PCB, you must have some training in drawing schematics. What software do you know how to use?

    Whether it is ExpressPCB or something else, your first task is to redraw the schematic into the software you are going to use. Then, whatever software you use will have a facility to convert the schematic into a collection of component drawings connected by ratlines. Then you will have to arrange those components in an orderly manner and connect them with traces.

    The assignment is not difficult if you have some training in drawing schematics, and there is help available here, but you have to describe your electronics background in order to get appropriate assistance.
     
    Last edited: Jan 19, 2012
  5. Wendy

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    OK, I have not built it, but Wookie came up with a 555 circuit that should slowly wind down. It is what I am going to use for my dice when I get around to them.

    Alice, if you are happy with the above circuit I will re-lay it out using express. I strongly suggest you duplicate my efforts though, if you are going to stay in electronics this is something you will need to learn.
     
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  6. R!f@@

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    Hmmm...I should have thought so...but OP did say

     
  7. tracecom

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    I think maybe the OP is long gone, but just in case, here is the schematic for the assembly pictured in her post.

    [​IMG]

    I have no idea which one she really wants.
     
  8. Alice.

    Thread Starter New Member

    Jan 18, 2012
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    Hi everyone, sorry for the late response.
    I posted pretty late and had to sleep. :p

    So, I'm currently in Electronics I. We haven't drawn schematics before, and this is the first time I've worked with Express PCB. I'm trying to work off of this:
    [​IMG]
    and I just found the other picture in my post as extra. Actually, I don't think my teacher cares which schematic I use, as long as it has a 555, 4017 and an LED die. Would the other ones be easier? And sorry if this is the wrong forum! Haha, I can repost if needed.

    Is it okay for the trace to overlap on Express PCB as it does in the diagram? I don't think so? But I can't figure out how to rearrange the components with doing so...

    And thank you Bill for your offer to help me lay it out, but I don't want to waste your time. :p I just don't understand how to rearrange the schematic to a PCB.
     
    Last edited: Jan 19, 2012
  9. Wendy

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    OK, I will use the one you showed. I will eventually design my own from scratch, as it constitutes what I do for fun. I did re-lay the 555 out because the stock 555 in Express is pretty bad. You will find this is a major feature in all these type programs, the ability to draw a new component from scratch is pretty important. This shouldn't take long, I figure about a day or so, so keep your eyes peeled for it.

    As a moderator I have the ability to look up your IP address, but your privacy is safe. I would suggest you post your general location in your profile so it will show up similar to how mine does.

    Being nosy, do you enjoy electronics, or is it just school? I started doing this as a young teen way back when. I've always had the feeling it goes much better that way, but I've seem people to whom it was just a job. I've felt sorry for them overall, this stuff is dry and stale if you don't like it. I looked at the Community search, you are the 3rd Alice to join this site. :D

    To do this right you must draw it as a schematic in the Express software, it is part of the process. You aren't wasting my time, it is what we do here. I am stretching the rules a bit making the file for you, but I think you need to see it to get an idea.

    I do a lot of drawing around here, I consider myself a local draftsman. Not all are good schematics, but you can see my normal methods (which do not involve Express) at these links.

    Bill's Index

    Introduction and PaintCAD

    Bill's Albums

    LEDs, 555s, Flashers, and Light Chasers

    You will find this site very friendly to beginners, it is one of our hallmarks. With a name like Alice we kinda assume you are female, this is extra points here (OK, at least from me). :D Since the field is dominated by nerds like me, we like seeing the occasional nerdette.

    If you have any questions how I did something this is where you ask.
     
    Last edited: Jan 19, 2012
  10. Wendy

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    Mar 24, 2008
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    OK, here is the Express schematic. Whenever you draw one of these you need to do a netlist error check.

    This document is used to help find and correct errors on your PCB file. You really can not skip this step, so I suggest you play with the Sch program a bit, get a feel for it.

    The good news is Express is fairly intuitive. The bad news is its more powerful cousins (Eagle for example) aren't.

    [​IMG]
     
    Last edited: Jan 19, 2012
  11. Alice.

    Thread Starter New Member

    Jan 18, 2012
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    Thanks Bill! That looks way better than mine. One question though, aren't the trace not supposed to overlap?
    This is what I have so far:
    [​IMG]
    I think biggest problem is trying to not get the wires to overlap? :S

    And yeah, electronics is fairly enjoyable. My teacher doesn't exactly teach from a textbook though... So everything is very unsystematic. Apparently half the things I don't know should just be "intuitive"... meh. The class isn't complicated but the information is just all over the place (ie, the internet) and I think I would probably have a better grasp if there were notes or something.
     
  12. tracecom

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    Are you restricted to using only a single layer board? If not, put some traces on the top of the board and some on the bottom. You connect a trace on the top to a trace on the bottom with a component lead through a pad.
     
  13. Alice.

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    Jan 18, 2012
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    This sounds magical. How do I do that on ExpressPCB? Is that the green trace option? And sorry, but what is a component lead? Is that the square thingy? (terminology lvl +1)

    And do the different trace widths make a difference? I have a feeling they do...
     
    Last edited: Jan 20, 2012
  14. tracecom

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    I haven't used ExpressPCB in a long time, so I have forgotten most of it. But at the top of the screen, there are three choices: a yellow, a red, and a green. Red puts the traces on the top and green puts them on the bottom.

    And notice on the bottom left of the screen that you can choose to see the only the red, only the yellow, only the green, or any combination of the three. When you are working on one side of the board, it can be nice to "turn off" the view of the other side.

    A component has wires or pins sticking out of it; those wires are the "leads." If you are laying out a two sided board and you place a component, the component will be on top of the board and its leads will go through the board to the bottom layer. Thus, there is an electrical path through the lead from the top to the bottom. If you have the board professionally made, the holes will be plated and the component leads only have to be soldered on one side. If the holes are not plated, the component leads will have to be soldered on both sides.

    Yes, the trace widths are important. Generally, wider traces are better because they can carry more current and are more resistant to peeling up while soldering.

    It sounds to me like your instructor is leaving a lot to your own investigation.
     
  15. Alice.

    Thread Starter New Member

    Jan 18, 2012
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    [​IMG]
    Thanks tracecom. Other than the the terrible layout and incorrect trace lead widths, is this somewhat correct? Do the green leads connect right now?

    And yeah, he likes to call the class "hands-on."
     
    Last edited: Jan 20, 2012
  16. tracecom

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    I can't really tell if everything's right, but it looks ok. Toward the bottom center, there are two green traces that are really close together. And you should know that it's ok to run traces under the resistor and capacitor bodies. Just don't run over the pads or other traces.

    Good luck.
     
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  17. Wendy

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    Mar 24, 2008
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    I see tracecom has gotten you sorted out. I make my own boards from scratch, so I don't use the second layer. What I do is to have jumpers, short pieces off wire like the excess from resistors, to jump over problem traces.

    I am very current on Express, though I have some techniques that are all mine. I tend to change the Express pads to ones I like better.

    Bill's Index

    How I make PCBs

    Your push switch is not connected. The green leads are the top side of the board.

    Are you actually going to build this? If so keep posting the latest layouts, we'll look for errors.
     
  18. Wendy

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    One last thing (maybe, I'll still be around). I don't have a lot of confidence in that schematic. Output 0 is not connected to anything, this leaves me feeling it may not have been tested. One of the curses of the WWW.
     
  19. n1ist

    Active Member

    Mar 8, 2009
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    When connecting a trace from one side of the board to the other at some point other than a thru-hole pin (like on the bottom common trace by the LEDs), you need to plave a via. It's a plated through pad (use the pad icon to place it) that is used to tie one side of the board to the other.
    /mike
     
  20. Wendy

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    This is if the board is done professionally. For home brew PCBs a wire is soldered on both sides.
     
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