you need 8 diodes, or an 8 input or gate, eight flip flops and a 5V
regulator (7805) and a 9v battery. or the buttons together with a the
diodes, also connect each button to a set input ona flip flop. use the or'd
button signal to strobe the clock line to all flip flops through a .01 uf
capacitor. use an 8 input AND gate to AND the negative outputs from the
flip flops and use the output of the gate to power the other side of the
switches.

(you can rework this with NOR/NAND logic if that is more convenient) - about
5 chips and 10 minutes to wire together.

you can do it with discretes or relays if that's easier for you, but with
TTL or CMOS logic you will use less power and it will be easier to move
around.

another way to do this is to use an 8 input latch, one input per switch,
triggered by the OR of the switches through a single shot circuit - might
take fewer chips.

look these chips up by type in a chip catalog and choose what is cheap and
available.


"Andy Asberry" wrote in message
...
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-----


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