MPX-16 census

[Tony Duell]

> 
> der Mouse wrote:
> >>I've never heard of anybody making more than double-sided PCBs at
> >>home (I would love to be proved wrong!).
> > 
> > 
> > I can't *prove* you wrong.  But I've spoken with someone who claimed to
> > have done it, and when I started asking questions, talked a good enough
> > line that I found it believable.  As she described it, you need
> > epoxy/fibreglass mix, which you cast a thin sheet of.  You then sand it
> > smooth, copper-plate it, and etch.  Slap on another coat of epoxy and
> > fibreglass, let it cure, sand it smooth, copper-plate, and etch.
> > Lather, rinse, repeat.
> > 
> > The hard part is of course quality control (and plated-through vias,
> > which you can get somewhere with by drilling holes before doing the
> > last copper-plating).  And registration of the layers.  But with
> > patience and attention to detail...after all, anyone doing this is
> > considering time to be worth a great deal less than money, or the job
> > would simply be shipped off to a commercial pcb fab house. :)
> 
> It's the sort of thing I can see our Mr Duell doing though.

s/Mr/Dr/ 

:-)

You do realise that I wrote the >> bit above. I have never tried making 
more than double-sided PCBs by hand. And for 1-off prototypes, where 
typically I want to try something, get it working, then move on to the 
next bit, I don't want a PCB anyway. It's possible to hand-wire stuff 
well up into the low 100's mf MHz range if you are careful. The main 
trick is to build everythign on a coppr ground plane (such as a pice of 
copper-clad board, unetched), stick down little bits of stripboard, 
strip side up, as component mounts, connect that which needs to be 
grounded to the ground plane with the shortest possible wires, and fit 
decoupling caps in the same way.

-tony