Taking a Drawing and Creating a PCB Gerber File

Discussion in 'The Projects Forum' started by sydcomebak, Jan 6, 2016.

  1. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    Shoutout to @GopherT and @absf for getting me this far...

    I took this:
    image.jpg
    and drew THIS:
    Capture_SM.PNG
    in MS Excel.

    The goal was a single-layer PCB where the switch and coin battery are mounted on the back side through the board and all other components on this side are surface mount. I'm pretty sure it's OK to have trace lines under the 555 chip, but I'm not sure about between the pins.

    First of all, is this how this kind of work is done? (Obviously not in Excel, but my hand drawings are embarrassing)

    Second, I DLed and installed KiCAD, but after 2hrs of videos and tutorial sites, I still don't have anything plotted. Can someone help me get a Gerber file set up?

    The dimensions of the octagon are 1 1/2" vertex to vertex or about 1 3/8" side to side or a 9/16 side length if that is where you want to start.

    Anyone interested in helping me out? Thanks!

    Edit: Parts List:

    Qty: Desc Mouser Link
    1 560K Resistor http://www.mouser.com/ProductDetail/Yageo/RC0402FR-07560KL/
    1 330R Resistor http://www.mouser.com/ProductDetail/Yageo/RC0402FR-07330RL/
    1 33K Resistor http://www.mouser.com/ProductDetail/Yageo/RC0402FR-0733KL/
    1 100uF Capacitor http://www.mouser.com/ProductDetail/Yageo/CC1206MKX5R5BB107/
    1 10nF Capacitor http://www.mouser.com/ProductDetail/Yageo/CA0612MRX7R9BB103/
    4 Side-Mount LED http://www.mouser.com/ProductDetail/ROHM-Semiconductor/SML-A12WTT86J/
    1 Vibration Switch http://www.mouser.com/ProductDetail/Adafruit/2384/
    1 Coin Batter Holder http://www.mouser.com/ProductDetail/Eagle-Plastic-Devices/122-7520-GR/
    1 PnP Transistor http://www.mouser.com/ProductDetail/Rectron/BC856A-T/
    1 555 Timer Chip http://www.mouser.com/ProductDetail/Texas-Instruments/TLC555CDR/

     
    Last edited: Jan 6, 2016
  2. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
    785
    Hi.

    To get their attention, we can tag them, like this: @GopherT and @absf .

    From your schematic you have +5vdc, and in your Excel diagram you have three LEDs. Is 5vdc enough to power three LEDs?
     
    sydcomebak likes this.
  3. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    Actually the coin battery is only 3vDC and the LEDs I've been using have held up pretty well. I think there are 4 LEDs on the diagram.
     
  4. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
    785
    You are absolutely right. :)
     
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  5. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    This tells me there's probably something very wrong if you can't read it.
     
    Last edited: Jan 6, 2016
  6. SLK001

    Well-Known Member

    Nov 29, 2011
    817
    227
    If this is your first project, I would NOT use 0402 parts. Use something like 0603 or even 0805 parts. Also, your schematic and your layout are not consistant. The 555 that you want to use is surface mount, but you have thru-holes on your board. Traces thru the "legs" of the 555 are okay, but check with the PCB house to find out minimum trace widths and minimum clearances. If you plan on doing this by hand, these traces could be dicey.
     
    sydcomebak likes this.
  7. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    OK, I'll look at that. I have no idea what the difference is, though. Which parts are you most concerned with?

    I'm sorry for the confusion. The 555 on the drawing was always meant to be Surface Mounted, I just used round points to show connections. My fault for the confusion.

    I will, thanks!
     
  8. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    On your Excel drawing you have the LEDs in parallel. They generally will not function well in parallel, (uneven brightness). Suggest you use a 330 ohm resistor in series with each LED. At 3V you probably should use a lower value like 100 ohms.
     
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  9. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
  10. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    There is the chance of LEDs being smashed up and not working, so I'd like the rest to function if one goes out.
     
  11. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    Adding the resistors will make sure that happens.
     
    sydcomebak likes this.
  12. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    o_O Really? I must know how this works!!!
     
  13. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    On the left is your current circuit. If one LED shorts, all of the LEDs turn off. On the right, the resistors isolate each LED. Short one LED and the other two stay on. Also, the resistors make the LEDs emit the same intensity.

    [​IMG]
     
    sydcomebak likes this.
  14. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    That. Is. Awesome... All the likes.

    Wait... They're still parallel circuits to each-other, the resistor and LEDs are in relative series... I get you now...

    Reworking the diagram now...
     
    Last edited: Jan 6, 2016
  15. SLK001

    Well-Known Member

    Nov 29, 2011
    817
    227
    The 0402 parts are 0.040" by 0.020". Almost like a speck of dirt. If your layout can take them, use 0805 parts (0.080" by 0.050", or ~4 times the area of the 0402s). The 0402s are never marked with the values. The 0603s and the 0805s are marked, so much less confusion. The 0402s were designed for pick-and-place machinary only. The others can be hand placed with ease.
     
  16. SLK001

    Well-Known Member

    Nov 29, 2011
    817
    227
    As for traces between the pins of the 555, there is approximately 0.028" between the pins. Using a 0.010" trace and 0.009" clearance on either side should be okay.

    You said you did the layout in Excel. How in the world did you do that?
     
  17. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    SLK, I'll get to your Excel question in a minute...

    Capture_SM.PNG

    @Lestraveled Does this look right?
     
  18. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    @SLK001

    Hey. I set all the columns and rows to the same width and height and by using borders and fills, I was able to create a sort of linear connection structure similar to what I was seeing people produce with the fancy PCB programs.

    First I just had printed out the octagon with all the grid lines and drew by hand, then I went in and used borders where I had made my lines. It isn't fast at all, but I have enough Excel experience that it's really easy.
     
  19. SLK001

    Well-Known Member

    Nov 29, 2011
    817
    227
    Wow... that's pretty clever - and time consuming. I can see how it is done now. Download Eagle and use the freeware version. The more that you use Eagle, the more that you will like it.
     
  20. sydcomebak

    Thread Starter Member

    Dec 13, 2011
    69
    5
    I have KiCAD, and I plan on learning it, maybe Eagle too, but I need this Gerber file to be on someone's desk ASAP so we can get 25 test boards printed. I'm starting a Kickstarter ASAP...
     
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