Taking a Drawing and Creating a PCB Gerber File

Thread Starter

sydcomebak

Joined Dec 13, 2011
69
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/

 
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Thread Starter

sydcomebak

Joined Dec 13, 2011
69
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.
 

SLK001

Joined Nov 29, 2011
1,543
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.
 

Thread Starter

sydcomebak

Joined Dec 13, 2011
69
If this is your first project, I would NOT use 0402 parts. Use something like 0603 or even 0805 parts.
OK, I'll look at that. I have no idea what the difference is, though. Which parts are you most concerned with?

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.
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.

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.
I will, thanks!
 

Lestraveled

Joined May 19, 2014
1,946
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.
 

Thread Starter

sydcomebak

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

Lestraveled

Joined May 19, 2014
1,946
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.

 

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Thread Starter

sydcomebak

Joined Dec 13, 2011
69
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...
 
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SLK001

Joined Nov 29, 2011
1,543
OK, I'll look at that. I have no idea what the difference is, though. Which parts are you most concerned with?!
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.
 

SLK001

Joined Nov 29, 2011
1,543
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?
 

Thread Starter

sydcomebak

Joined Dec 13, 2011
69
@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.
 

SLK001

Joined Nov 29, 2011
1,543
@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.
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.
 

Thread Starter

sydcomebak

Joined Dec 13, 2011
69
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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