Make hobbyist PCBs with professional CAD tools by modifying "Design Rules"

It's nice that there are some professional circuit board tools available to the hobbyists. Here are some tips for using them ito design boards that don't need a professional fabricator to actually MAKE them...

Step 1: Introduction, part 1 - my gripe

There are numerous tutorials on the net about making your own printed circuit boards (PCBs.) Toner transfer, photo-sensitized PCBs, sharpies; all sorts of information...

Likewise, there are are a number of Computer Aided Design packages (CAD) designed to help create PCB designs, possibly with accompanying schematics. Some of these have low-cost versions aimed at students and hobbyists.

But I see on various web pages PCBs created with these CAD packages, by hobbyists, that are not "friendly" to actually being fabricated by hobbyists using the methods described on the PCB pages. A lovely published PCB is not nearly so useful if it requires the $50+ typical minimum price from a professional board maker.

I don't have any doubt that with the right equipment, and supplies, and some practice, you can get good enough at home PCB fabrication techniques (take your pick) to produce high quality board of significant complexity, with fine traces, small holes, and so on. But a lot of PCBs don't really need that complexity, and it would be nice if they were DESIGNED in such a way that you didn't NEED a lot of experience in PCB making to get a working PCB.

This document contains some hints on configuring a CAD package to create boards that are easier to manufacture in a hobbyist environment. It's based around Cadsoft's Eagle CAD package, but the principles are relatively general and should be applicable to other CAD packages as well.

Comments

[elmobd3]

Thanks alot :)

[jefremichel]

thanks so much for this info! new to eagle and slowly climbing the learning curve.

[Higgs Boson]

How exactly do you remove the silkscreen to only print the traces and pads?

[blinkyblinky]

There is a layers icon.

See this: http://www.instructables.com/id/Draw-Electronic-Schematics-with-CadSoft-EAGLE/step12/Fiddle-with-the-layers-a-bit/

Just do the same on the board side of things.

[williamgracia651]

It is a well informative and tutorial blog, it is easier to prepare for electronics hobbyist .But the PCB should explain with block diagram with different section, and any way it is helpful for many hobbyists.


http://www.itechlance.com/

[hondaman900]

Is there a way to start over with the PCB layout? I used autorouter and didn't like the routing, especially after I moved components. I ended up deleting tracks thinking autorouter would simply redo them, but now I'm stuck. Seems like there should be a re-route process/option, or at least the ability to remove a PCB design and start over from a schematic. Any suggestions? I can't find this via user manual, Eagle's help file or Google.

[westfw]

Next to the "route manually" button is a "ripup" button that converts tracks back into air-wires.  To get rid of everything, click "ripup" and then click the traffic light that appears in the top toolbar.   Or type "ripup ;" in the command-line window.

[Surferdude]

You can also use the grouping box to ripup a section of a board. Click the ripup tool, click the dotted line box (Group), select the area, the CTRL-right-click it.

[flyingpumpkin]

 Where, exactly, does one find the menu option to increase the trace width?

[Surferdude]

There's a much easier way. Just select the "i" tool and then click on the thing you want to change. It will bring up a dialog box that let's you change most of the attributes that apply to whatever you clicked on!

[kdrummer]

I just found that you can use the "change" tool (looks like a wrench) and select a new width from the dropdown.  However, you have to click on each trace segment in order to change it.  Can anyone help on how to automate this for changing many traces?

[FazJaxton]

Select the change tool, setting "Width" and the desired width. (The author is saying that you can do this by typing "change width 1.0mm", but you can select it with the mouse and the wrench tool as well). You can then select the "Group" tool and select everything to be changed. Then right click on any part of the selection and choose "Change: group". This will change all selected traces at once.

[AvrDon]

I've been using Express PCB for the last couple projects. 3 board for 59.00 usd
Software is pretty easy to use. I needed board that I can order and just install the parts. Nice work!
Don

[Aplonis]

Thank you kindly for this instruction. You surely have saved me much frustration as I found it just after DL'ing Eagle and prior to my first creation. I'm just now getting back into this after my divorce since I gave up such hobbies when I got married 20-some years ago. Back then I used to lay out double-sided circuits at 4X size with red and blue tape on acetate laid down onto a light board. Then I had to photo-reduce the red and blue sides separately into a pair of black masques. This newer way is going to be very much cooler, I'm sure.

[hannobisschoff]

Thank you very much for your extremely helpfull tutorial.

[panic mode]

nicely done, congratulation.

i was doing same thing until i got access to mill which makes prototying simpler (you don't need to etch) but the soldering is a bit harder.

couple of months ago i started using KiCAD because I needed to make some larger bards but could not afford paying for software (KiCAD is free). it was quite easy to get familiar with too.

[Sockles]

Thanks so much for clearing this up for me! I always routed myself because I never could get the traces big enough for my cnc to route.

[ookid]

.8 mm or .8 cm?

[Algag]

i beleive .8cm or 8mm

[raghavendraelectronic]

Hi one and all., myself rbk., I want to design pcb., can any one please help me which software should i use for designing pcb. I'm new to design . So please guide me about softwares. Thanks to any replies

[Algag]

use eagle cad it is available for free with limitations for any nonprofit, prototyping, and home projects the instructables on how to use it are a dime a dozen

[hgk]

I am using eagle's free version to do a double sided board at home and would like to add some pad area to the top traces as the board will not have plated-thru holes. Is there a way to do this ( or to edit out unwanted bottom pads if printing the top layer with pads?). Is there any other common way of connecting the top traces to components? Thanks for any help.

[hgk]

The hard way:
Open a renamed copy of finished project.
Goto board and select top, pads, and dimension layers.
Draw a wire x-hair somewhere on the board for future alignment reference.
Group, copy, and paste a copy of everything alongside (pads wont copy).
Add vias to traces wherever you want top layer solder pads. Via sizes can be adjusted to suit.
Goto renamed schematic then group and delete everything.
Goto board and group and move everything into the now blank dimension area. Use the wire x-hair as an alignment reference.
Now print the board to use for the top etch pattern.
If there's an easy way please let me know.

[westfw]

It doesn't do what you want if you select TOP, PADS, and VIAs layers, and then print as normal, perhaps with 'mirror" selected? here's sample "print to file" output from a 2-sided board I have:

[Eonir]

Oh. Looks like you've got yourself a ground loop. Just sayin :D Should a lightning crash nearby, a current would flow within your ground plane. That can usually cause damage. Of course, that doesn't really matter, the odds are close to zero, so don't worry. I'm just dropping random knowledge like a clumsy librarian.

[hgk]

At the time I felt that I didn't want all the pads etched on the top layer, just wanted the ones that were connected to top traces. But looking at your finished layout it looks just fine to have everything there. Thanks again.

[westfw]

Ah. Yes, it would be a challenge to only produce the top pads that HAD to be there; I don't know any way to do that.

[westfw]

I'm not sure what you mean. There are some "ticks" to making a double-sided board that won't have plated through holes (probably a good subject for another Instructable) that mostly consist of ensuring that the pads that pass a signal from top to bottom layers only occur on components where you can easily solder both the top and bottom sides (or use EXTRA vias, which is opposite the usual optimization for professionally manufactured PCBs.)

[hgk]

Sorry for the confusion. Normally one would etch the bottom layer and pads together and etch the top layer without pads. I would like to etch the top layer with just the pads associated with the top layer traces. Is there any way to something like that? Bottom line: how do I electrically connect the the top traces to the components on a home made double sided board without including some pad area along with the top layer traces. Thanks once again for your help.

[westfw]

Normally both top and bottom copper layers include the "pads" EAGLE layer; you just include PADS in whatever output technique you're using. I'm working on an instructable about doing output from EAGLE, which is shaping up to be largely a discussion of LAYERS and what they really mean (and some of "why?")

[janw]

Hi, Really great tutorial and very clear to understand. But I must say that the standard settings for eagle suits me well. I must admit that I don't use the tonertransfer method but photosensitive PCB's. On the other hand, I do not have fancy equipment: I use a Philips facial tanner to expose the PCB's to UV light and drill press to drill the holes.

[hgk]

When making a board using the toner resist method, is there a way to set up multiple copies of the board lined up to print on a single page?

[jeff-o]

I wish! At best you can print two, three or four copies on the same page by running the same paper through, and aligning the design to different corners (possible in Eagle, not sure about other programs). The downside is that on each pass the paper darkens a bit from scraping toner off the rollers, so with this method you really can only do four boards max. Hmmm, maybe there's a way to "panelize" the designs, though. Does anyone know if Eagle can panelize?

[westfw]

Free Eagle will panelize up to the limits of the free version (80x100mm); there are some ULPs (eg panelize.ulp) that aid in the duplication of labels and such. And there are tricks you can do with postscript output, or gerbers, to panelize outside of EAGLE. Output tricks was supposed to be the subject of another instructable, but I got a bit bogged down.

[jeff-o]

Well there you go. I'll have a look for those ULPs. I've got the paid student version so I could panelize a slightly larger board.

[mircerlancerous]

I make home made PCBs all the time using the Toner Transfer method with photo paper. With regard to the software, while Eagle is a powerful software package and a free one at that, it is much more than you need for casual circuits. I prefer PCB123. It is easy, simple, and free. When you're done your design just choose print schematic, click black and white, select your layers and you're done. It's probably no good if you're planning on involving a board shop other than the PCB123 people but for homebrew it's great. All depends on how much learning you want to do.

[westfw]

I didn't mean this instructable to be entirely specific to EAGLE; other CAD packages probably have very similar features and even terms (like "design rules.") They're sort of industry-standard. The thing that attracted ME to EAGLE was the support for non-windows operating systems...

[jeff-o]

Excellent work! Wow, I just checked the published date. Nice to have your work suddenly recognized again, eh? Anyway, thanks for this. It's good to know that you can increase pad sizes using DRC. That often screws me up, with the drill pulling up the pad...

[westfw]

Yes; it's a bit odd to have Instructables "featured" and become "popular" when they predate the existence of those features... One wonder what other gems are back there.

[renoir]

Nice tutorial! It explains a few things that I was mis-understanding, like the word "check" = "modify" :-). I assumed it would just complain about pad sizes, etc, not change them for me. Nice tip about drili-aid.ulp too :-)