Stealth Pilot wrote:

On Wed, 16 Jul 2008 21:37:32 -0500, "Pete C."
wrote:


Andy Asberry wrote:

This project is for a student Quiz Bowl (think Jeopardy). Eight
handheld push button switches that turn on an led indicator (one for
each player) and energize a buzzer. It must also block all other
buttons so there are no simultaneous lights. Oh, and must be battery
powered.

Just to clue you in on my capabilities, the last course I took in
electronics was for tube radios. I can solder.

--Andy Asberry--
------Texas-----

One of the cheap little basic programmable microcontrollers ought to do
the job, something with 16 I/O lines preferably so you don't need
additional support chips. I believe Radio Scrap carries some of the
Parallax micros, as does Fry's.

I had an idle moment today and this little puzzle came to mind.
here is roughly how I would do it in one of the little GE PLC's.
(ladder logic using logicmaster)

it will look crap in a proportional font. use courier new in notepad
and you will see the typical logicmaster paper logic print.

you need to add the subroutine declaration and call in the main block
(placating the spell checkers out there).


Ow.

Simpler in basic. Just a loop doing a peek of the input port looking for
a value other than 255 (presuming switches pull low). Looping a some 10s
of killoHertz should be plenty fast in any of the current little micro
chips. After that it's a simple test to see which line went low or if
there is a tie. Gives you the ability to handle that rare tie better,
perhaps a rapid flash on the appropriate LEDs, can also do sound effects
easily.