Homebrew PCBs

Hi Alan,
        I built a similar unit for receiving Radio Faxes
from around the world VIA a shortwave radio. My unit used
stepping motors from a floppy. That's 20 years ago! Here
is a picture of the unit. I used some of Ralph Taggerts
circuits and some of my own. I went on to design a circuit
board that goes in the computer. I used FAX_Dhals.

see machine at:

http://crankorgan.com/kleinfax.JPG


                                     73s

                                    John






--- In Homebrew_PCBs@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> Hi Steve, John, list,
> 
> check out Jon E's photo plotter:
> 
> 	http://www.artsci.wustl.edu/~jmelson/photoplot.html
> 
> While it plots to film, I think you can get a few ideas from it.  
And
> there are advantages if you can generate a good film, such as 
exposing
> as many boards as you want from it.  
> 
> But yes, I DO like the concept of mechanical etching!  And the 
software
> to do the isolation tool paths is very interesting to me 
(programmer). 
> As well as the controller it's self!
> 
> I don't know the linear speed of Jon's photo plotter (perhaps it's 
that
> the film is faster then the photo resist), but I'm surprised it 
couldn't
> be made to work.  A laser out of an HP laser printer?  Then you'd 
need a
> mirror to get the light over to the "pen lens" and down to the 
board. 
> Put the hole laser thing on the XY carriage?  Yeah, that could work!
> 
> Perhaps we'll get a little more info on the HP, and someone can try 
some
> experiments on exposing the resist on a board with a laser!  And who
> cares if it takes a long time?  Controlling the size of the 
laser "dot"
> on the board with an aperture would be the tough part.  I'm told 
that
> commercial photo plotters use an aperture disk, which is a set of
> "films" with an appropriate mask.
> 
> 
> Alan  KM6VV
> 
> 
> Steve Greenfield wrote:
> > 
> > Yep, far too long to expose, and the problem of "blooming". UV
> > laser, anyone?
> > 
> > That sounds do-able! It would just require modifying a pen with 
one
> > of those carbide point marking pens. I think you could probably
> > just spray something like one coat of black fast drying laquer to
> > scratch through.
> > 
> > And one of the things I've always liked doing to boards I make is
> > sign them. Couldn't do that when I made some with the vinyl 
cutter.
> > 
> > So the only issues are paint that will scratch away cleanly and
> > that it leaves a wide enough opening after etching.
> > 
> > Steve Greenfield
> > 
> > --- crankorgan <john@k...> wrote:
> > > Hi,
> > >    Nobody liked my light on a plotter idea. I was told the
> > > light source would have to move too slow. The board would take
> > > way to long. Ok, I use Mechanical Etching bits myself. But what
> > > if you coated the whole board with resist. Then you put a sharp
> > > point in the plotter. Have the plotter do isolation paths. Then
> > > the board goes to the acid.
> > >
> > >                                           John
> >