Interested in learning to Design PCBs

[csf]

Okay so recently some ideas have been popping in to my head and have me wondering just how hard it would be to learn how to design PCBs.

I have done some basic web reading on the topic and while it seams complex, it doesn't seam impossible to learn.

Do you guys here think it's something someone can teach them selves how to do?

[RJ]

Sure you can. You can do about anything you want if you really want to, Trust me on this!

RJ

[Jeffl]

I'm sure you can.  Speaking as somebody who is learning.  Maybe just not as fast as with classroom training.  Besides reading on forums and tinkering I find You Tube a good source for how to education.

[chrisatpsu]

if you plan on making  (etching the pcb's) try readin up on proper disposal of the chemicals used.  I've seen where it's being more and more of an issue for some locations.

this part of it has been a deterrent for me.

EDIT: forgot to mention...  if i do need a board made, i might go with a compant that offers the service, more professional look, and no mess to cleanup afterwards  ; )

[n1ist]

It's certainly possible to teach yourself board design; I did that myself, and have since done many boards from small adapters to 8-layer boards and BGAs...

There are a few steps:

- Choose the software package.  Some (like ExpressPCB) are tied to a specific board house.  Others (like the free Eagle) have limitations on size or selling boards.  I started out with ExpressPCB and moved to KiCAD for personal projects.  I have also used Allegro (but that's out of any normal person's budget...).

- Draw the schematic.  While you may be able to skip this step for simple boards, I don't recommend that.  It's easier to design and debug when you have a real schematic.  You will have to create schematic symbols for components that aren't in the tool's library, so figure out that part too.

- Do the layout.  If you have a tool that displays ratsnest (also called airwires - lines that show which pins need to be connected), that will help figure out placement.  Start by drawing the board outline, and placing stuff that must go in a fixed location (connectors, switches, displays, triacs lined up for heatsinks).  Then place the larger or many-legged parts to minimize airwires crossing each other.  When laying out the board, think about other part orientations.  Often I will rotate a part to simplify the routing.  I will also reassign pins to I/O ports on processors (if possible) to help here.

- Post the layout and let others comment on it.  Often, you are so involved with your own designs that you miss out on some things that will make the design better or simpler.

- Have the board fabricated.  If you have a single sided layout (or even a simple 2-sided one where you can solder z-wires to take the place of plated-through holes) you can etch the board yourself at home.  Otherwise, send it out for fab at a board house.  If you look at some posts here or at DIYC, you will find some lists of good fabs.  I have used PCBGeek, PCBCart, and Gold Phoenix in the past.   BatchPCB, Seeedstudio, and DorkbotPDX have some interesting proto options, but it's often not that much more to get a whole panel done in China.  Just be prepared to wait about 3 weeks.  If you want it faster, ExpressPCB, Advanced Circuits, or one of the US houses can get it to you as fast as next day, but it's going to cost more.

/mike

[mokeefe]

Mike,

I too have been thinking about dabbling in some circuit design and microcontroller programming. That's great info you provided. Nothing like hearing first hand from someone who has "been there, done that".

-Mike

[csf]

Thanks guys for all the great information and the positive feed back.

I would probably have my boards prototyped by a company, not to deal with the chemical issues, one I found some good reviews on is PCB International, has any one dealt with them? One thing that stood out to me about them is that they have a service that ranges from 25-75 dollars where you can send them all your diagrams if you don't have pro software and they will put the design in pro software and look it over for you and then give you the pro files, then if you order with them they will take off 5% of the order total. Or do you guys think you can safely get away not using pro software?

[RJ]

I am not even trying to tell you how to go but to give an example of why if it is IMHO a better idea to do the pcb yourself you ay it cost up to $75 to have them do it.

 Well you can download Diptrace for free to use up to 300 pins and for a upgrade you can buy the 1000 pin package for $125

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for the non profit license. So less than two pcbs and you are saving money and learning to do it yourself with more flexibility.

Just my opinion.

RJ

[csf]

RJ thanks for the information, the more I know the better. If I didn't want suggestions I wouldn't be posting about it in public, you guys all have allot more experience on the subject then I do, and I appreciate any feed back you guys can give

[Trepidati0n]

RJ makes a pretty good point. If doing small prototyping (1-2 boards) with thorugh hole parts and you plan on doing many "iterations", then DIY PCB etching makes sense.  0.1" type spacings are pretty robust to home etch solutions...even down to 0.05" with practice.  

A couple of other little things once you get further along.

1. make sure you prototype on a breadboard if you can
2. If the design is a bit sensitive in terms of speed or power..slow it down or lower the currents and still breadboard
3.  When making a PCB, order the parts ahead of time...print out your PCB on paper and make sure the parts line up.  You would be amazed how many times footprints that you think are right...aren't.

The biggest reasons I can think of to go to an etch house for small amounts:

1. You really don't want to deal with chemicals
2. You really need a two side board with lots of traces.

[RJ]

I'm sorry I was not very clear. I meant the layout of the pcb. I never found two sided home etching to be worth it fo me.

RJ

[Jeffl]

On this topic.  I just ordered a few breadboards.  I have ordered from this company twice in the past year and have had good luck.  They had groups of pieces like resistors, caps, diodes etc so it worked out well to purchase an assortment pieces for playing.

They have breadboards on sale now and the prices and shipping are the best I had found as long as they were on sale.

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[n1ist]

For what we are doing here, I find KiCAD to be as good as the "professional" software, and it is free without any restrictions.  The only places I have run into limitations have been in things that we will not run into for DIYC/DLA applications (matched length busses, true differential routing) and I am sure those are being worked on.

You really want to do the schematic capture and layout yourself; if you farm them out, you may not be able to make changes without paying for those too.  It's not that hard.  Feel free to ask questions or post a board for review; there are a bunch of us who will be happy to help out.

I agree about home etching; for other than a simple single-sided board, it's easier to send off a design to be fabbed, and that way I get solder mask and silkscreen.  It's not even worth wirewrapping a prototype anymore (though I do still do protos on a whiteblock for some stuff).

/mike

[tmtfield]

I am glad you guys brought this up. While I am no where near ready to start designing PCB's, I would like to have a better understanding  of what it is that I am soldering.

Does anyone know of a source of good information on basic circuit design and theory? Basically a low level overview or electronics book for "Dummies"

Thanks for all of the info so far.

Tim

[chrisatpsu]

To get a feel for the really basic of basics. (like, what is a transistor, what is a resistor?)  I'd suggest those 100 in 1 (or 250 in 1, 500 in 1)  electronics kits.
Not only do you get a book that explains everything, but you get a hands on lab, where you can build simple circuits and get a feel for what the components do.

As you progress, you might want to go to a local college and take a class if offered. If not, you might want to go online and pickup an electronics course book from a place that sells college Course materials. (i think half.com sells college text books)   

if you want to learn more about a particular item, try goin to the manufacturers website, and trying to download any kind of data or spec sheets.
Data sheets can tell you all kinds of things, like the pinouts of an item (usuful for transistors, and IC's), or even power requirements.