Homebrew PCBs

Stefan Trethan wrote:
>>>Alan King wrote:
>>>
>>
>>   Well few production items make sense to worry about having double 
>>sided
>>without through holes anyway.  And I'd still disagree with that opinion 
>>on other
>>grounds, in general it develops your layout skills far more to work on 
>>good
>>topology and have the minimum number of jumpers with everything on the 
>>bottom.
>>Trivial to go to some easier method, so hard to consider it a bad 
>>habbit.  For
>>the most part designing towards any goal strengthens your skills for 
>>designing
>>towards other goals, the particular goal for a particular case hardly 
>>matters.
>>I could design for months straight this way, and then still have no 
>>problem
>>doing something else, and I bet most other people could too..  I mainly 
>>do SM
>>single sided boards now for no holes because it makes sense, but it 
>>hasn't made
>>me bad at still doing a double sided when needed.
>>
>>Alan
>>
> 
> 
> I fully agree with that.
> you have to work with what you get here and now, and using it the best way 
> possible.
> Keeping things simple is no bad habit i would say.
> 
> Also keep in mind how many "low end" electronics is still on single sided 
> paper/resin board.
> 
> I hate it when i come across the most simple amateur circuits in the web 
> which need to use
> both layers, with a design complexity that would allow building them on 
> half a layer ;-).

   Check this case in unnecessary design:

http://www.rigelcorp.com/r535j.htm
http://www.rigelcorp.com/__doc/8051/R535JASSM.pdf

   It's a development board I got a long time ago, like 94 or 95.  If you look 
in the assembly manual, there's a picture in the first 2 or 3 pages.  Don't see 
a photo right now on the site.

   Truly silly thing was it was a 4 layer board.  Way back then when they were 
very expensive.  And totally not required, when a friend and I got ours, we 
noticed this and looked at it very closely for WHY was it 4 layers before 
putting components on.  Not the chips, they're all fairly simple routing and 
could have easily been taken care of.  Instead it was the simple components with 
many crossed wires, the resistors, caps, and transistors.  They placed, and 
didn't move a few minor items to make it a double sided board.  The board was 
high quality too, not laminated sheets but etched, thick layer resist, more 
copper, then other etch or similar.  The green highly translucent type and you 
can see the quality and no thick lamination sheet for the other layers.  Suppose 
it could have been laminated though, with very thin sheet.  Of course it was 
probably never high quantity, and he may have been making his own 4 layer 
boards, so may not have been too big an issue.  Still would have been only a few 
minutes work to reduce it to a two layer and have a much simpler board.  If they 
were buying these all this time though they've wasted a heck of a lot of money. 
  Very good board great for soldering, but much of a waste..

   I still have it, will take a small pic so you guys can see it next time I run 
into it.  Board probably cost $25 instead of the $5 it should have back in 95 or 
so, may not be such a difference now but think of the lost $20 each pop.  At 
that time at least they probably sold hundreds a year of these.  Probably 5 or 
10 K in waste a year if they didn't make it themselves.  Of course not too long 
after PIC's etc started getting really popular and cheap and made more sense. 
Never even used the board much for this reason, got into PICs more right after 
getting it.

   It would be very nice to find these materials though, and get home made 
boards up to this quality level if possible, it does stand out as one of the 
best boards I've ever worked with.  The good through hole plating may have been 
much of this extra quality though, things didn't lift etc with any amount of heat.



   And I wonder if they ever fixed their LCD code, had a bug in the Enable line 
wait logic that made it very spotty until I fixed a couple of lines.  We thought 
it was something flaky with our LCDs until I found it and everything worked 
after that, and I bet most everyone else with one thought the same.