Eagle 5.4.0 light ?

Discussion in 'General Electronics Chat' started by Mathematics!, Jun 11, 2009.

  1. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    1,022
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    I am trying to design my own PCB boards using this free software.

    My question is their are .sch files and .brd files

    What are the .brd files for since they seem to have the traces over lapping in different colors. I don't think you could use these to iron into a copper clad board. So why do the have these ?

    For the .sch files are these the ones you should create to iron on a copper clad board (i.e PCB etching...)

    Their is one other file extension I saw that is .ctl don't know the significants of these files and what they do?

    Any input would be great because I just started using this software and I don't know what is what.
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    The.sch are schematic files; the .brd are board files. The different colors on the .brd files are for the different layers. If you are using the toner transfer method, then print only one layer at a time. You select what you want to see and print with the tools menus.

    John
     
  3. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    1,022
    4
    Using the toner transfer how can you have different layers.
    Basically you are printing the design off and ironing the ink onto the copper clad board?

    I don't see why we need .brd? ( or what the different colors are used for since you only need one color to iron it into the board usually black) I don't even see how you can have different layer using the toner method?????

    Should I just use the .sch files to create my design for the copper clad board.

    Also how do you change the size of the design for printing purposes?
    (i.e how do you make it bigger or smaller once you make the design)

    Is their anyway to convert the .sch files to jpegs ?

    Thanks for any help I am still learning the software.
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    The board has two sides, often referred to as top (usually red) and bottom (usually blue) on the board editor. Many people make double-sided boards with toner transfer. You iron on the toner for the design on one side, flip the board and repeat the process for the other side.

    What would you propose using, if not a board file?

    I don't think that will work, but there is no reason you can't try it that way. Let us know what happens.

    The print dialog has a scale factor you can enter. It is right in the middle of the page.

    Yes. Export as png or any other format that is listed, then convert.

    John
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You wouldn't want to use the schematic capture portion to create the board. Use it to create the schematic, and then do the board layout in the PCB editor.

    Read through this tutorial: http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=108

    Also, it's best to export images in .PNG format, as .JPG is a "lossy" format; the image won't be clear.
     
  6. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    1,022
    4
    I guess I still don't get it.

    For the brd files they have all different colors running into each other if you took this and printed it out and ironed it onto the copper clad board.

    The colors in some places would overlap. Not to mention what would be the point of the different colors ironed into the copper clad board?

    I would think all you need to do is design 2 .sch files one for front and one for back of the copper board. ( if you even need it two side thats)


    I guess I don't know when I create a new project what I should start designing first the .sch file or the .brd file ????
    And how everything gets link together.
     
  7. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
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    Starting with the schematic (.sch) is much easier as it is an easily readable representation of a circuit and how it works. The board file (.brd) puts the schematic parts into physical dimensions of existing parts that you can purchase. It also allows you to places the traces on a PCB that make the connections as shown in the schematic. The schematic (.sch) helps guide the design of the PCB (.brd).

    When you do the toner transfer of the board file you have to turn off all layers except one. You should not see all of the intersecting different color lines on the file as you are about to print it. You have to print out the top and bottom layers independently. Only print one color at a time... I would guess that it may also be better to print out in black as well...

    Only a signal schematic is needed for a board, whether it has one side or two. The PCB editor allows for flipping components from one side to the other along with the corresponding traces.
     
  8. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    1,022
    4
    Ok , I follow you so you design the .sch first and then the .brd sizes all the components to the correct sizes of the actual components you buy.

    But when I look at the examples of some of the .brd files they have many colors. I know you said you turn the colors off all but one when doing the toner transfer but what is the purpose of having all the different colors if you only ever use one. Maybe possible 2 if you count both sides????

    Also once you have a .sch file how do you associated it to a new .brd file ?
     
  9. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    The different colors are just for different layers. By looking at the color of the track you can tell what layer the trace is on.

    I am not sure what examples you are looking at, but a board is not limited to 1 or 2 layers. The ones you build at home are limited to one or two layers for ease of making in your basement but the ones that are manufactured by a PCB company can build large numbers of layers into their boards. I have worked on 14 layer boards in the past. The copper is stacked with insulating material and pressed together. Each layer is etched before the next insulating layer is stacked on top of it. They can stack as many layers as needed. Start with two copper layers then make four and six and eight and so on....

    I am sure many have worked on boards with more layers than that. The different colors help a great deal when dealing with that number of layers.

    I think there is a button is the schematic editor to transfer the design to the pcb side of the software. It has been a little while since I used Eagle so I am not exactly sure what they call it. Maybe someone else can chime in here.
     
  10. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Correct.

    If you're doing just a single-sided board, you can turn off all layers except the one you're using. The default colors for traces are red for layer 1 (top), blue for layer 16 (bottom). Vias/pads are generally green. Other colors are used for part outlines, text, solder masks, etc. This makes for easy visual identification while you are creating the board design.

    You start with the schematic capture.
    Tip: the first thing I do in schematic capture is to go to frames.lbr, and place a suitable frame's lower left corner on the "+" on the screen, which is reference point 0,0. If you don't drop a frame, you may have trouble figuring out how to make a printout of your schematic. An "A" size frame is for 8-1/2"x 11" paper. I usually use a landscape format.

    Once you have your schematic drawn and it passes Erc (Electrical Rule Check) with no errors, you can switch to the board; if a .brd file doesn't exist for the .sch, it will ask you if you want to create one. By default, it will just dump all of your parts in vertical rows on the board.

    Let me say it a different way for emphasis - don't create a board unless the schematic passes the Electrical Rule Check, or your life will be most unpleasant. Erc is the lowest icon on the left menu in the schematic capture.
     
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