How to REALLY start designing PCBs?

Digital tools for electronic work: software for pcb design, schematic drawing, circuit simulation, parts inventory tools, ...

How to REALLY start designing PCBs?

Postby meffcio » 21 May 2012, 19:32

Hey, fellas!
I've searched through the Internet and read many, many advices on designing PCBs, but to be honest - I've never really found what I need. There were tutorials showing some things about ground placement etc, but when I draw a schematic and export it to board designing program I just don't know what and how to do next. The ratsnest seems like one big random something and doesn't really help placing components. I can, let's say, place some pots and jack inputs regarding the whole design of the effect, but that doesn't help much, as there's a whole bunch of other components that need to have place. And as I said, ratsnest always looks to complicated, no matter how much I try to place everything correctly. I know there are some rules about placing voltage and ground paths, separating low current circuits from high current ones, etc., but since guitar fx are rather simple circuits are those really necessary? Do you guys have any advices for a PCB noob? What did already help YOU learn designing PCBs?

For this message the author meffcio has received thanks:
Duckman (22 May 2012, 18:24)
User avatar
meffcio
Solder Soldier
 
Posts: 189
Joined: 25 Mar 2009, 19:31
Has thanked: 8 times
Have thanks: 16 times

Re: How to REALLY start designing PCBs?

Postby Dirk_Hendrik » 21 May 2012, 21:02

That is a question!

And the quick answer is practice, practice, practice.

A few quickies from my book.
- high impedance connections as short as possible (avoid a world of oscillation and noise pain)
- Long connections first. When having all routed and having all board space occupied except for one connection that goes from one board end to another one is an incredible pain in the butt. Having to replace a few short connections in far easier.
- roughly follow the schematic (hint; Schems read from left to right, pedals go from right (input) to left (output). Do a horizontal swap on the schem so it reads from right to left too)
- route short power supply connections straight away. Connect all these in the end. For supply lines one jumper wire usually reaches more solutions than having routed the full supply power in one trace and then having to add multiple jumpers to get signal lines connected.
- Take an existing design and the schem and copy that to see how the designer of that board worked his way through exactly your question.

and
practice, practice, practice.
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

For this message the author Dirk_Hendrik has received thanks: 3
asatbluesboy (20 Oct 2012, 07:04), Duckman (22 May 2012, 18:23), Seiche (21 May 2012, 21:45)
User avatar
Dirk_Hendrik
Old Solderhand
 
Posts: 4239
Joined: 03 Jul 2007, 09:44
Location: Old Amsterdam
Has thanked: 255 times
Have thanks: 1036 times

Re: How to REALLY start designing PCBs?

Postby madbean » 21 May 2012, 21:21

I started by emulating some of the methods used in the Tonepad layouts. Like Dirk says, just do a lot of them. You'll find the tricks after a while. Keep your component placement logical and group areas into patterns, too. Sometimes it's good to start right at the input, sometimes it's easier to route power and then other times it's good to work several areas simultaneously and then connect them together. Always keep in mind where you want your I/O wires to go, what dimensions the board is restricted to and how organized the final design looks. Aesthetics (IMO) actually play a part. A good looking layout is well organized with the connections being direct and easily traced with the eye.
madbean
 

Re: How to REALLY start designing PCBs?

Postby marshmellow » 22 May 2012, 00:42

marshmellow
Cap Cooler
 
Posts: 456
Joined: 16 Aug 2007, 08:31
Location: Germany
Has thanked: 14 times
Have thanks: 124 times

Re: How to REALLY start designing PCBs?

Postby DrNomis » 22 May 2012, 01:16

I tend to use vero/stripboard for the majority of my pedal builds, mostly because I don't have any etchant, toner-transfer film, or toner powder for my laser printer, when I'm designing my vero layouts I use the schematic as a guide and I try to make the layout follow it, then I'll usually go through a few design tweaking iterations till I come up with something I'm happy with, like Dirk said....practice...practice..practice..... :thumbsup
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.
User avatar
DrNomis
Old Solderhand
 
Posts: 6899
Joined: 16 Jul 2009, 05:56
Location: Darwin,Northern Territory Australia
Has thanked: 123 times
Have thanks: 405 times

Re: How to REALLY start designing PCBs?

Postby phatt » 22 May 2012, 07:56

Hello meffcio,
Your REAL Problem maybe that you are trying to skip the most important aspect! It's called a breadboard or similar and you proto the circuit and iron out all the bugs BEFORE you even dream about a PCB. By design that will get your brain tuned into what parts need to go where and why.

*The old saying of more haste less speed applies here.*

I know the net is a nice place to find a circuit you want and a quick dip in the tank produces a nice little circuit. Then Cross your fingers and hope it works as well as claimed,, often they don't :(
You will never learn much that way so bite the bullet and proto a circuit you think looks close to what you want and then tweak it around.

There is nothing worse that making a PCB only to find you have to bodgey it all up with flying leads to fix design issues.
These type of circuit will just slow your progress.

With a Breadboard on my bench I can print a schmo of something that looks promising, then in one afternoon I get to hear exactly what it does with my own ears through my own amplifiers. I write a quick observation on the schematic and bottom draw for future reference if needed. Very few circuits make onto Cad let alone PCB.

also learn to use simulation software as it's a handy cross-reference. Between the sim and a breadboard there is not much that I can't work out in a relatively short time. ( A scope would be nice but for the stuff I need to build I really don't need one)

To give some idea of how long it takes to develop a deeper understanding,, When I started out I spent close on 10 Years just trying to perfect a spring reverb circuit.
Some might say I obviously did not know what I was doing,, which is of course would be correct :lol: ,,, but I now have a killer spring reverb that would eat most others with brandname fronts.
The bonus was that I learned one hell of a lot about analog circuitry in that time which I would never have gained by downloading circuits and hoping it works.

A side note,, few of the reverb circuits found on the net work well enough to want to build one. heck I should know as I've built or proto'd most of them, Winky.
Phil.

For this message the author phatt has received thanks:
sinner (22 May 2012, 13:49)
phatt
Transistor Tuner
 
Posts: 1099
Joined: 04 Aug 2010, 06:17
Location: Morayfield SE Qld AU
Has thanked: 0 time
Have thanks: 287 times

Re: How to REALLY start designing PCBs?

Postby bato001 » 22 May 2012, 11:52

Like every other poster to this thread replied, layouts take practice whether they are Vero or PCB. I recommend you try laying out a few small circuits on Vero then try to translate the Vero to PCB to get a better feel for component and trace placement.
"Ever wondered how some of your favourite guitar players got their tone? Me too. Probably a good amp and lots of practice." Little Lord Electronics Homepage
User avatar
bato001
Resistor Ronker
 
Posts: 322
Joined: 19 Feb 2009, 22:31
Location: NJ
Has thanked: 46 times
Have thanks: 58 times

Re: How to REALLY start designing PCBs?

Postby John Ricky » 22 May 2012, 12:55

I spent four years as a design engineer for a big mobile phone company. While I've only ever driven the CAD tool once or twice, I spent a very big chunk of time sitting by the layout techs and talking them through where the tracks and components will go. And the first pass at the PCB always took a very long time, simply because it would invlove repeated placement and removal of components. After four years I was fairly good at this, althoguh it was sucha long time ago I suspect I've forgotten most of it...:D

The aim was always the same - anything sensitive was shielded, parasitic capacitance was minimised (i.e. how close are your ground planes to signal tracks, and this does still matter at audio, as you'll loose treble) and power supplies used reasonably thick tracks, but definately not power planes. Components would get dragged onto the board, and routed in. If it didn't look good, it would come back out again. It took a very long time...

Cheers
John
User avatar
John Ricky
 
Posts: 11
Joined: 30 Apr 2012, 15:53
Location: UK
Has thanked: 0 time
Have thanks: 2 times

Re: How to REALLY start designing PCBs?

Postby DrNomis » 22 May 2012, 14:17

A good thing is to start designing layouts for very simple circuits and gradually work your way up to designing layouts for more complex circuits, also, keep outputs as far away from inputs as physically possible, having a high-impedance input right next to a low-impedance output is just asking for trouble with self-oscillation in high-gain circuits, and, make sure your power-supply rail is properly/adequately bypassed, try to arrange the circuit grounds in a Star-Grounding system (very important for reducing hum-levels in guitar amps), make sure you have polarized components correctly oriented, if you really want a professional looking layout orient resistors, caps, etc so that the values can be read easily without having to contort yourself into knots, have a look at how components are oriented on a PCB from say a piece of High-End audio, or Military Spec. equipment for an example..... :thumbsup

And also, take your time to make sure everything's right.... :thumbsup

Give yourself regular breaks at say 15 minute intervals while you're working on a layout design.... :thumbsup
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.
User avatar
DrNomis
Old Solderhand
 
Posts: 6899
Joined: 16 Jul 2009, 05:56
Location: Darwin,Northern Territory Australia
Has thanked: 123 times
Have thanks: 405 times

Re: How to REALLY start designing PCBs?

Postby Dirk_Hendrik » 22 May 2012, 18:29

DrNomis wrote:, or Military Spec. equipment for an example..... :thumbsup


Since I don't do PCB design for that kind of appliances (and therefore never searched for these requirements, if exixtent) , could you point me out where to find mil specs for PCB design.

And,
How mucht would you learn from a military device PCB design if you don't have the requirements that were set for that appliance?
Sorry. Plain out of planes.

http://www.dirk-hendrik.com
User avatar
Dirk_Hendrik
Old Solderhand
 
Posts: 4239
Joined: 03 Jul 2007, 09:44
Location: Old Amsterdam
Has thanked: 255 times
Have thanks: 1036 times

Re: How to REALLY start designing PCBs?

Postby meffcio » 22 May 2012, 20:29

Damn you guys! Always there to help a noob.. :D
Seriously, thanks for all the advices. Most of them are kinda logical, but still I weren't capable of discovering them by myself. :oops: I think that now I'll just start with some silly Bazz Fuss design, and when it's perfect, choose something more advanced, and so on.
User avatar
meffcio
Solder Soldier
 
Posts: 189
Joined: 25 Mar 2009, 19:31
Has thanked: 8 times
Have thanks: 16 times

Re: How to REALLY start designing PCBs?

Postby madbean » 22 May 2012, 20:59

meffcio wrote:Damn you guys! Always there to help a noob.. :D
Seriously, thanks for all the advices. Most of them are kinda logical, but still I weren't capable of discovering them by myself. :oops: I think that now I'll just start with some silly Bazz Fuss design, and when it's perfect, choose something more advanced, and so on.



That's a good idea. Do a few designs then etch and build them. Once you get the bug, you'll never want to stop. It's great fun to make your own layouts and have them actually work :)
madbean
 

Re: How to REALLY start designing PCBs?

Postby Dirk_Hendrik » 22 May 2012, 21:37

What I should do is press print screen a few times next time and post the shots including comments. Could help some getting insight in the process. (and especially the crap getting the last connections done), or better, getting insight in how I deal with the process. How a circuit is, correctly, layouted is highly dependent on the guy doing the layout. Madbean as an example makes layouts in a way I'd never do or even think about. But the end result always looks terrible good and when physically building the design it shows all important factors (pad sizes, component shape size etc.) were taken into consideration.
Sorry. Plain out of planes.

http://www.dirk-hendrik.com
User avatar
Dirk_Hendrik
Old Solderhand
 
Posts: 4239
Joined: 03 Jul 2007, 09:44
Location: Old Amsterdam
Has thanked: 255 times
Have thanks: 1036 times

Re: How to REALLY start designing PCBs?

Postby Nocentelli » 22 May 2012, 22:02

Dirk_Hendrik wrote:What I should do is press print screen a few times next time and post the shots including comments...


That would be amazing (presuming you're serious, I know you're pretty dry)....

I'm personally strictly vero at the moment, but i'm eager to get started on some proper pcbs, especially now there seem to be some cheap-ish smallscale pcb fabrication online now. So far, I've opened Eagle a few times.... then closed it again.
brownwhopping wrote:How can I learn by reading threads an making circuits, when some day I can see a lawsuit or somebody beat me in the face for that?
User avatar
Nocentelli
Tube Twister
 
Posts: 2119
Joined: 09 Apr 2009, 08:06
Location: Leeds, UK
Has thanked: 903 times
Have thanks: 857 times

Re: How to REALLY start designing PCBs?

Postby Duckman » 23 May 2012, 03:29

Here's a good reference
You do not have the required permissions to view the files attached to this post.
User avatar
Duckman
Opamp Operator
 
Posts: 1521
Joined: 20 May 2009, 02:45
Has thanked: 369 times
Have thanks: 143 times

Re: How to REALLY start designing PCBs?

Postby Aharon » 10 Sep 2012, 16:59

RG Keen has a book on PCB design at GEOFEX.
Aharon
Aharon
Solder Soldier
 
Posts: 187
Joined: 17 Aug 2007, 00:39
Location: Canada
Has thanked: 24 times
Have thanks: 8 times

Re: How to REALLY start designing PCBs?

Postby CodeMonk » 20 Oct 2012, 02:12

As said by everyone else, practice, practice, practice.

How I approach it is to stare at the schematic for awhile, mentally placing components on a PCB.
Considering component size and purpose.

I usually go from left to right with the schematic.
I also try to keep in mind how I want the last few parts to be placed.
When I lay down the first component, I try to imagine where the next 3, 4, 5 or more components go.
As I add more components, I continue doing this as well as back-tracing the circuit 3, 4, or 5 components as well.
I takes a lot longer doing it this way, but my success rate is much higher this way, for me at least.
User avatar
CodeMonk
Degoop Doctor
 
Posts: 440
Joined: 02 May 2011, 08:20
Has thanked: 16 times
Have thanks: 56 times

Re: How to REALLY start designing PCBs?

Postby DrNomis » 21 Oct 2012, 10:17

meffcio wrote:Damn you guys! Always there to help a noob.. :D
Seriously, thanks for all the advices. Most of them are kinda logical, but still I weren't capable of discovering them by myself. :oops: I think that now I'll just start with some silly Bazz Fuss design, and when it's perfect, choose something more advanced, and so on.




No worries, we were all newbies once, including myself.....actually I miss those newbie days..... :thumbsup


PCB designing is kind of an artform, like music.... :thumbsup
Genius is not all about 99% perspiration, and 1% inspiration - sometimes the solution is staring you right in the face.-Frequencycentral.
User avatar
DrNomis
Old Solderhand
 
Posts: 6899
Joined: 16 Jul 2009, 05:56
Location: Darwin,Northern Territory Australia
Has thanked: 123 times
Have thanks: 405 times

Re: How to REALLY start designing PCBs?

Postby Dirk_Hendrik » 25 Oct 2012, 18:21

DrNomis wrote:.....actually I miss those newbie days..... :thumbsup


Hmmmm. preps the joy of discovering something new.....

but the frustration.... the endless frustration. Naah not that again :blackeye
Sorry. Plain out of planes.

http://www.dirk-hendrik.com
User avatar
Dirk_Hendrik
Old Solderhand
 
Posts: 4239
Joined: 03 Jul 2007, 09:44
Location: Old Amsterdam
Has thanked: 255 times
Have thanks: 1036 times

Re: How to REALLY start designing PCBs?

Postby Duckman » 25 Oct 2012, 19:33

Dirk_Hendrik wrote:but the frustration....


Thanks to that, you're a happy builder now 8)
User avatar
Duckman
Opamp Operator
 
Posts: 1521
Joined: 20 May 2009, 02:45
Has thanked: 369 times
Have thanks: 143 times

Next

Return to Software Room

Who is online

Users browsing this forum: No registered users and 2 guests