# newbie question - jeoperdy game circuit

Discussion in 'Electronic Basics' started by Ashton, Nov 3, 2003.

1. ### AshtonGuest

Hi,

I am working on some project that works like the Jeopardy Game. What happens
is, there are three teams, with buttons infront of them, and on each team's
desk is a light bulb.

After asking the question, the first one to press the button gets the ligth
go on, on their table, while the rest of the team's buttons are disables,
hence their ligth bulbs dont go on even if they press their button(as ong as
one light is on.. the rest are disabled).

Anyone who can give me an idea of how to do this? I know how to work if it
were only two teams, but what do i use (if realys, any specific one? ) that
would help me resolve this issue?

Thank you for the help in advance,

Ash

2. ### Hal MurrayGuest

I am working on some project that works like the Jeopardy Game. What happens
Two suggestions...

If you can do it for two, then start with AxB, BxC, and AxC. Then feed
the results of that to another layer of the same logic. That should
give you a simple result.

I'd do it with silicon rather than relays. I's use a PIC or AVR, and
do it in software. First run each input signal through a pair of FFs
to avoid metastability. (That's probably included in the PIC/AVR front
end.) Then in software, spin until at least one bit comes on. If
there is only one, your job is done. If two or three, then you have
more work to do.

One approach is to change the rules of the game. Say everybody gets
an extra \$100 in the case of a tie. (Or only the teams that tied.)

Or you could run a counter in the background, and use the counter to
decide ties. Say divide the counter by 2 or 3 and use the remainder
to decide.

3. ### GPGGuest

_/ __
+V -o/ o----|------------| |
| B--|& |o- A
.-. C -|__|
| |
| |
'-'
|0V
_/ __
+V -o/ o---|-------------| |
| A --|& |o-B
.-. C -|__|
| |
| |
'-'
|0V

_/ __
+V -o/ o--|-------------| |
| A --|& |o- C
.-. B -|__|
| |
| |
'-'
|0V
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de
Triple 3 input nand gate, eg 4023. Outputs can drive a load through a suitable
interface. Connect points marked with letters as shown.

4. ### Richard CrowleyGuest

There are also bus-based circuits out there that can run any arbitrary
number of stations. Most are quite simple and one can find several examples
online.

5. ### Keith R. WilliamsGuest

Yep. Just pick one at "random". If the quantization period is short
enough and your "random" choice is fair enough no one will notice.

6. ### ashtonGuest

How do i work with this situation...

______
inA--------> | | -------->outA
inB--------> | |--------->outB
in-C-------> | |--------->outC
------------

The logic is to be:

Whichever input point is first to send the signal (example, value 1),
then the other inputs are discared, and the ouput goes to the point
that did the first input.

Example would be, if three players press the button, the first player
who presses the button gets the light on his table switch on, while
the other player's lights on their respective tables dont go on, even
if they pressed the button (thats because they pressed it late)

Anything i can use to accomplish this?

Thanks

7. ### William P.N. SmithGuest

Well, you could probably do this with discrete logic, but for a couple
of bucks you could make it with a PIC micro. The cost of the wiring
and the table lights and such are going to swamp the cost differential
between the two, and development kits are pretty cheap (\$36 for the
PICkit 1).

9. ### Bill BowdenGuest

You could try this "Who's First" indicator circuit. It uses 3 parallel
SCRs with a common cathode resistor so only one SCR can be triggered
to light one light. Fairly simple, no micros or logic chips needed.

http://ourworld.compuserve.com/homepages/Bill_Bowden/page7.htm#game1.gif

-Bill

11. ### GPGGuest

Andys is not made for a lot of wires. Draw it out. The first switch
will inhibit others. Output is logic low, uses 1 very cheap IC. Speed?
Have not checked all available chips (and the one suggested is not
alone) but the res sponse time is sub microseconds

12. ### Franc ZabkarGuest

http://www.designnotes.com/CIRCUITS/quizmaster.htm
http://www.ee.washington.edu/circuit_archive/circuits/F_ASCII_Schem.html#ASCIISCHEM_002
http://www.mitedu.freeserve.co.uk/Circuits/Misc/quiz.htm

- Franc Zabkar