problems with learning eagle

Discussion in 'Electronics Resources' started by 1-3-2-4, Jun 6, 2012.

  1. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
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    I've been trying hard but so far my projects have been simple but this program is hard.. I'm just trying to do a simple board with just 4 LED spots but I can't figure out how to do the first piece of the board.

    Should it be this hard?
     
  2. BSomer

    Member

    Dec 28, 2011
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    106
    Sparkfun electronics has a tutorial series on how to use Eagle...
    http://www.sparkfun.com/tutorials/108

    There are also a number of tutorials on youtube.

    Where are you getting stuck? Is it making the schematic or the layout of the board? When using eagle it may be better to start by making the schematic first. Then make the board from the schematic so the two are linked and there will be a smaller chance of errors when routing the board. Although human error still applies to the schematic. :)
     
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  3. MrChips

    Moderator

    Oct 2, 2009
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    We have a number of members here on AAC with lots of experience with Eagle.
    Just tell us your problem and I'm sure we'll find the answer.
     
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  4. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    In my head I know the layout since I already did a mock up on a perfboard it's just the program and me have different ways of doing things..

    I'm used to drag and drop type of layouts.. and last time I tried eagle I had a hard time.. however I did not do the schematic first but went right for the layout..

    my design is very very simple.. 4 LED's would be on like a 2" x 10' board connected in series with a voltage regulator and a resistor.

    That's the basic one.. I have another but it's a bit more complex and I want to just learn my way around first.
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    As BSomer says, start with the circuit schematic. This will make life a lot easier in the future.
     
  6. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
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    I'm stuck somewhat now.. I'm trying to do the LED's which are superflux Philips Lumileds however I don't seem them in the library nor do I see my LM2940T listed
     
  7. nerdegutta

    Moderator

    Dec 15, 2009
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    If you cannot find your exact component, and you are not doing simulation, then find a component with similar footprint. And, oh yes, start with creating the schematic, then move on to the board layout, and place your components.

    Do you have a pencil drawn schematic?
     
  8. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
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    Yeah I found some stuff with the same footprint, I don't have a drawn out one but I can do one
     
  9. nerdegutta

    Moderator

    Dec 15, 2009
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    If you do that, we'll get a better idea of what you want to achieve. At least I will. Then maybe later today, when I'm finished at work, I might give it a try, in Eagle 6.2.0.
     
  10. BSomer

    Member

    Dec 28, 2011
    433
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    I have to admit that is one part of eagle that is sometimes a daunting task, trying to find that one component you need for your design amongst the hundreds of other stuff in the libraries. The search sometimes works flawlessly, other times not so well. When searching for a component I use an asterix before and after the part number and drop the letters in the number, i.e. *2940*. Then you can narrow down the results.

    One other thing I noticed is the size of board you are trying to make. Depending on the version you have (paid or free), there are some limitations to the size of the board. The freeware version only allows for a board area of 4 x 3.2 inches.

    I downloaded the freeware version of diptrace, though I haven't dug into it too much yet. Diptrace does not have a size limitation but instead has a limit on the number of pins, 300 I think.
     
  11. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1

    here is a little quick one I did

    the block on the left is a voltage regulator.

    here is where I'm at now
     
    Last edited: Jun 7, 2012
  12. nerdegutta

    Moderator

    Dec 15, 2009
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    I've done some assumptions:

    VDD > 12vdc
    Regulator is LM7812T

    LEDs are RED with:
    Vf = 3.2v
    mA= 20

    With 4 LED in a chain you would give: 4 x 3.2 = 12.8v. Which is more than our power supply. Therefore I think it's wise to split them into two strings with two LEDs in each string.

    With Ohms law we get:

    2 x 3.2 = 6.4v
    12 - 6.4 = 5.6
    5.6 / 0.02 = 280R

    Resistor = 280Ohms

    Is this what you are trying to do?

    [​IMG]

    Link to big view.

    To smooth things a bit, you might want some caps along with the regulator. This circuit is not finished, but just as an illustration...

    Comments on the calculations are welcome.:)
     
  13. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    Well the application is going in the car so I factored in 14.4V but I'm using a 12V voltage regulator on it.

    I forgot to provide the specs of the LEDs :(

    the vf is 2.5 it's rated for 70 mA but I'm driving them at 60 mA they are superflux red-orange LEDs.

    I got around 33 ohms in my calculations
     
  14. nerdegutta

    Moderator

    Dec 15, 2009
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    Wrong answer... can't help. Read the TOS.
     
  15. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    Oh i forgot

    well never mind then I will find it elsewhere, thanks for your help anyways!
     
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