Etching circuit boarda

Hi,

I did exactly what you mentioned, it lays a plane around them but it touches everything except wirepads.  Here's a picture:

You see all those smd resistors and caps?  The pads where the routes are touch the ground plane because the ratsnest tool didn't isolate the those pads on them.  Yet it isolated the ones on the wirepads.  It makes no sense to me.  These are standard 0603 resistors and caps I got from the "rcl" library.  Maybe I should've put all my traces on the top layer?

Thanks!

Hi Mike,

Yes, basically your SMD devices are currently on the top layer (because they are in red), but the traces are on the bottom layer (blue), so they

are not touching.

There is a similar problem with the IC, because it is on the top layer, but the tracks are on the bottom layer.

Ordinarily EAGLE will automatically identify this and won't allow you to do this. Did you draw the schematic first, and then change the yellow airwaves into tracks?

(If you skip the schematic step, there is a chance for a lot of errors to occur).

Ahh, I see.  Yeah, I drew the schematic first and then had it generate the board.  Then I manually placed the routes. 

Now that I've messed around a little more I can see that I will need to put my traces on the Top as you said and it looks like it works perfectly.  Thanks!!!

I got my instructions for doing this from someone who said I should put my traces on the Bottom...

-m

No problem. Good luck with the board!

By the way, since this is going to be a home-etched board and likely single-sided, the green pads will be on top only too, so any wires that you connect will have to be fed through from the bottom of the board and soldered to the top, same as the SMD devices, or perhaps solder in some pins but from the top.

In the photo in post number 7, I actually had the same problem with the long DIL header you can see at the top-left of the board. What you can't see is that I had to lift the header quite high and solder it from the top side of the board, so actually that header is raised somewhat from the surface of the board. It's rather messy but is fine for a prototype of course.

The board you can see mounted on screws hasa DIL header soldered from the underside (you can see the parallel row of soldered joints near the top of the board).

So, home-etching does have some challenges ocassionally, due to the absence of through-hole capability. At the bottom of the large board, you can see near a nut that there are many solder blobs; these were through-hole bits of wire. Again, rather messy but works.

Yeah, I had planned to feed the wires through the bottom.  I even have some traces I need to connect by wire because my chip needs 3 separate power voltages on something like 12 different pins and I can't get them all to connect without drilling through and running wires (that's what the smaller holes are for on that board)...

I notice on your board you either have a huge isolation value or orphans is off (lots of etched away space in the middle of the board around the chips and the things connected to them).  It looks clean.  I may need to do that too depending on how this all comes out (instead of having ground EVERYWHERE).

Thanks again,

-m

You're right, to be honest that board may not be EAGLE, or may be done by hand. I think I was just trying to save a bit of etchant rather than have a ground plane (possibly the underside may have one if it is dual-layer). It was a very long time ago (I experimented with quite a few CAD packages over the years, but eventually stumbled upon EAGLE from version 4.x and I've been using it ever since (although I do occasionally use some other packages).