Guy -n- Gals,

     I just have to get my 2 cents in. Here goes.

     If you are building something just once and have analog or high speed
     digital circuits, then use point to point wiring techniques and a
     ground plane prototype board like Vector 8003.

     If you have relativly low speed circuits (ie. digital less than 25
     MHz) then by all means use wire wrap. It will get you there faster.

     But, if you ever think that the device will be produced in any
     quantity, then get a PCB/Schematic package (I use HIWIRE II).  You may
     make mistakes on your first Prototype run, but you can easily cut and
     jumper your mistakes. And besides, you will be much closer to the
     final design PCB.

     Joe Dowlen


______________________________ Reply Separator _________________________________
Subject: Re: Board construction techniques (was: Yet another LED proj
Author:  pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU> at SMTP
Date:    11/15/96 11:24 AM


> >> Well this is a religious argument. Each has their advantages and
> > disadvantages:
> >>
> >> Breadbording: Quick to throw together. Easy to change. Entirely too easy to
> >> change.
> >>
> >> Wirewrapping: Quick to throw together presuming you have the equipment.
> > Sockets
> >> cost more than PCB sockets. Too much extension from the bottom of the
 board.
> >> Fairly stable and generally easy to modify.
> >>
> >> PCB: Please tell me how to make an inexpensive, consistent PCB. While it
> >> may be easy to do, many of us have not set up the design tools and
 equipment
> >> to put it together. I'll gladly take a lesson in easy PCB making.
>
> I used to do it and finally gave up and got boards made.  The problems I had
> included:  Getting top and bottom side layers to line up (or I would go with
> one layer and lots of jumpers), Chemical storage and disposal (it's illegal
> to put in the garbage here in Toronto AND you have to pay somebody to take
> them), film manufacturing (although I got pretty good at it towards the end
> with a laser printer that could do transparencies), board developing (Again
> Chemicals and their disposal as well as making a lightbox to hold the film
> against the card) and drilling (the drills cost a fortune and break so
> easily).  I once (note the "once") made a board using tape, stencils, and a
> PCB marking pen.

This kind of testimony seems to debunk the original primise that making
PCB's are so easy that wire-wrapping is unnecssary.

> [ Canadian PCB manufacturer info deleted for brevity... ]
> [ Same for Vector boards... ]

>
> >> Each has advantages and disadvantages. Generally while I'm designing and
> >> testing I wire wrap. Easy to put together a semi-permanent board that can
> >> be changed if necessary. I'm willing to examine PCBs but all I read in the
> >> sci.electronics newsgroups is how difficult it is to get good boards....
>
> Steve Ciarcia, when he was creating projects for Byte, used to create
> semi-embedded cards for his projects.  He would put on Connectors and such
> and wire Vcc and Gnd and then Wire-Wrap the rest.  Maybe if somebody's
> energetic, they could do this for the PIC?

I'm still trying to find a good argument for using PCB's for development.
The statement that PCB's are trivally easy to do started this thread.

Breadboards are good if the project is extremely small. But their instability
and cost generally makes them unusable for anything other than fiddling.

PCB's are the way to go once the project is developed, tested, and working.
But for development? I don't think so.

So that leads me right back to wire wrap. Inexpensive (tool and wire for
less than $20), can be used in permanent situations, and simple modifications.
Gives nearly instant gratification like breadboards, but can be thrown in a
box and expect to work.

BTW I learned by hard experience that auto wire wrap tools like Slit-N-Wrap
and guns are generally bad news. Hand strip - Hand wrap is the way to go.
Every board I've ever had wrapped worked, can't say the same for the auto
tools.

BAJ