Re: gEDA-user: [pcb] "first board" docs

[Dave N6NZ <n6nz@xxxxxxxx>]

DJ Delorie wrote:
 > I've been pondering the "your first board" chapter of the getting
 > started guide.

555? People still use them? They cost as much as a whole microcontroller 
these days.....

But a microcontroller isn't a  good first project, so a 555 has it 
merits -- you don't need a device programmer.

I kind of like the idea of producing some useful piece of test 
equipment.  How about another blast from the past: a very simple logic 
probe?  Mainly just an LED and a buffer -- to modernized it you could 
make it work with both 3.3V and 5V logic :)

A simple power supply board built around 3-terminal regulator also uses 
only a few commonly available components, and is useful enough that you 
might actually build more than one.

How about a continuity tester?  A 555-based beeper for output would make 
this a pretty useful tool.  Once you get the first one to work, you can 
use it to find broken traces in your next board.  Bit of a bootstrapping 
problem on your first one, though....  But anyway, it could be built on 
a long skinny board, solder a piece of wire to one end for probe, add a 
pigtail with  ground clip, enclose the whole thing in some shrink tube, 
and you've got a handy tool.  I guess you need to put some AAA's or 
something in the package too.... shrink tube would make changing 
batteries a pain, I guess.  OK, I'll leave the packing issues up to you...

Code practice oscillators are a moot point these days :(

-dave


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