gEDA-user: alarm clock update

[DJ Delorie <dj@xxxxxxxxxxx>]

I got the first board populated today.  It works!  The only ECO so far
was to increase the LED resistors for the three power monitor LEDs,
they were too bright.

http://www.delorie.com/electronics/alarmclock/

Unfortunately, Digikey put the wrong parts in the PIC24's envolope, so
I'm short two CPUs.  I'm sure they'll fix that error before I need the
other two boards.  Has anyone else had problems with Digikey shipping
the wrong parts?  This is the second time it's happened to me.

The gelatin paper trick didn't work.  The paper wasn't flat after it
dried, the first sheet wrinkled in the printer, and the second just
didn't let go of the toner after I laminated it.  I went back to the
special paper for the paste mask.  Also, I'm giving up on 5 mil masks;
even on the big parts it put down too much paste.  I could have gone
with smaller holes, but I might as well use thinner brass and get a
faster, more accurate etch.

Also, a part note: I've found the ultimate zener diode!  The Sharp
PQ12DZ51 12v LDO regulator has a typical drop-out of only 0.2v, and
drops off gradually - i.e. below 12v it gives Vin-0.2v (down to about
2v), above 12v it gives 12v.  Plus it has an enable pin that's TTL
compatible and 5v tolerant.


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user