Homebrew PCBs

You guys probably already know this.  But I got a real kick out of 
this - when it worked the first time I tried it.

I have discovered one neat trick with Eagle.  It is trivial to get a 
beautiful "ground plane" around all your traces. While still at 
the "rats nest" stage of layout...just place a polygon (simply a 
rectangle really) on the same layer as your traces.  Make it the 
size of your entire board.  When you auto route...the autorouter 
will automatically isolate all your traces from this "ground plane". 
So, it is not really a "ground plane" as it is isolated from 
everything else. But, with one little "blue wire" you can make it a 
ground plane, if you want.  I just do it because it will save on 
etch time. 

Jim

P.S.  BTW, I don't use the default Eagle design rules.  I modified 
them to make traces twice as wide...and also to leave twice 
the "isolation" between traces. With the fatter traces...it is 
easier to get a perfect Toner Transfer.   I Googled "Eagle Design 
Rules" and somebody had posted a writeup on how to change them to 
new, consistent values. Very nice of him.

----- Original Message ----- 

From: "jzmuda2000" <hwhacker@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, June 13, 2006 10:41 AM
Subject: [Homebrew_PCBs] Eagle Tip - add a nice looking "ground plane" to 
your boards


> You guys probably already know this.  But I got a real kick out of
> this - when it worked the first time I tried it.
>
> I have discovered one neat trick with Eagle.  It is trivial to get a
> beautiful "ground plane" around all your traces. While still at
> the "rats nest" stage of layout...just place a polygon (simply a
> rectangle really) on the same layer as your traces.  Make it the
> size of your entire board.  When you auto route...the autorouter
> will automatically isolate all your traces from this "ground plane".
> So, it is not really a "ground plane" as it is isolated from
> everything else. But, with one little "blue wire" you can make it a
> ground plane, if you want.  I just do it because it will save on
> etch time.

Set its signal name is GND and Eagle will start routing to it.

Hi Mike,

> > I have discovered one neat trick with Eagle.  It is trivial to get a
> > beautiful "ground plane" around all your traces. While still at
> > the "rats nest" stage of layout...just place a polygon (simply a
> > rectangle really) on the same layer as your traces.  Make it the
> > size of your entire board.  When you auto route...the autorouter
> > will automatically isolate all your traces from this "ground plane".
> > So, it is not really a "ground plane" as it is isolated from
> > everything else. But, with one little "blue wire" you can make it a
> > ground plane, if you want.  I just do it because it will save on
> > etch time.
>
> Set its signal name is GND and Eagle will start routing to it.

You can also add the ground plane after you've finished routing. It's
important to use the polygon tool and NOT the rectangle tool.

After creating the polygon (on the bottom layer), rename it to GND (as
Mike mentioned) and then click on Change Isolation and change the
isolation  to an appropriate value (you have to click on one of the
polygon edges).

When you click on the Ratsnest, it will redo the isolation. If you
already have ground traces, you can rip them up. I find that when I
open the board, the ground plae doesn't always show up properly.
Clicking on rats nest redraws it properly.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

>I find that when I open the board, the ground plane doesn't always 
>show up properly.

If done properly, the "copper pour" should never show until you hit 
ratsnest after opening the board (assuming the box "Ratsnest 
processes polygons" under miscellaneous settings is checked). Well, 
more correctly, it never shows in my case. I see only the polygon 
frame (basically a rectangle in its simplest form) around the board 
or area.

This is by design IMO since there is no command that I'm aware of to 
roll back the pour and allow for relevant changes to items that the 
pour may obscure once it's done/redone during an editing 
session....Correct me if there is.  In other words the pour itself, 
like everything else, is never "written in copper, bits or bytes", 
think of the board opening as a graphical regeneration process based 
on saved data with the pour regeneration step being held back until 
you hit ratsnest. Perhaps there is some option to have polygons 
automatically processed at board opening but I'm not aware of it. 
Also, things may have changed with later versions of Eagle.

For those new to this, here is a picture of a board with a poured 
ground plane. As others have stated, this is dead easy with Eagle;

http://www.pbase.com/eldata/image/57044297

--- In Homebrew_PCBs@yahoogroups.com, "Dave Hylands" <dhylands@...> 
wrote:
>

--- In Homebrew_PCBs@yahoogroups.com, "Dave Hylands" <dhylands@...> wrote:
>
> Hi Mike,
> 
> > > I have discovered one neat trick with Eagle.  It is trivial to get a
> > > beautiful "ground plane" around all your traces. While still at
> > > the "rats nest" stage of layout...just place a polygon (simply a
> > > rectangle really) on the same layer as your traces.  Make it the
> > > size of your entire board.  When you auto route...the autorouter
> > > will automatically isolate all your traces from this "ground plane".
> > > So, it is not really a "ground plane" as it is isolated from
> > > everything else. But, with one little "blue wire" you can make it a
> > > ground plane, if you want.  I just do it because it will save on
> > > etch time.
> >
> > Set its signal name is GND and Eagle will start routing to it.
> 
> You can also add the ground plane after you've finished routing. It's
> important to use the polygon tool and NOT the rectangle tool.
> 
> After creating the polygon (on the bottom layer), rename it to GND (as
> Mike mentioned) and then click on Change Isolation and change the
> isolation  to an appropriate value (you have to click on one of the
> polygon edges).
> 
> When you click on the Ratsnest, it will redo the isolation. If you
> already have ground traces, you can rip them up. I find that when I
> open the board, the ground plae doesn't always show up properly.
> Clicking on rats nest redraws it properly.
> 

WOW!!!   Not only does this save on etching copper by creating a
monolithic groundplane, it's ****EASY*** and ***CONSISTENT***.

Thanks for the great tip, Dave.
This is so, so, so much easier than drawing polygons.
THIS IS THE WAY TO GO!!!!

Nice job.   Thanks so much.   Now making a groundplane is cake.

Alan

Hi Mike,

> Thanks for the great tip, Dave.
> This is so, so, so much easier than drawing polygons.
> THIS IS THE WAY TO GO!!!!

Credit is really due to Jim (the original poster).

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@...> wrote:
Hi Mike,
 
> Set its signal name is GND and Eagle will start routing to it.

How do you prevent isolated GND fill from being used?  How do you 
specify trace width for connecting?  My connections are all zero 
width...

Thanks,
Dennis

Hi Dennis,

On 7/10/06, dl5012 <dl5012@...> wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@...> wrote:
> Hi Mike,
>
> > Set its signal name is GND and Eagle will start routing to it.
>
> How do you prevent isolated GND fill from being used?  How do you
> specify trace width for connecting?  My connections are all zero
> width...

You can choose Change->Width and click on the polygon that describes
the ground plane to control the width of connections.

If you Do Change->Orphans->Off then you won't get any orphaned fills.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/