Fire in the hole! Or in the brain maybe...

12:10. The bloody fire alarm goes off. Here's our posse. Dazed and confused we set afoot to the gathering point.

I told them I was going have lunch. I'm not letting a stupid false alarm spoil my precious lunch of course! On the way to the sandwich shop I passed the bell. I felt like ripping it off but it was too high. Yes, my 6'4" didn't cut it this time...

When I came back the fire brigade had arrived. I thought they'd all be in Victoria right now but apparently only the hobby fire brigade is allowed to go interstate.

This is where people who read the building's evacuation plan gather. I think it's about 50% of the people inside the building.

I found our posse and ate my lunch and had a good time in the sun. For 10 minutes. Then we walked back. I don't know why. I think somebody thought we waited long enough and the sheep effect did the rest. Anyway, the fire trucks were gone when we arrived.

I'm now working on this little piece of electronics. I want to set/reset a combination of relays. I want uncontrolled inputs A and B (one of them, they shouldn't be triggered at the same time) to put respective points C and D in a controlled 'state'. When either C or D becomes 'high' I want 'X' to send out one pulse that can be used to set the relays. So basically if point A gets triggered 10 times (5 rail cars driving over the switch) I want point C to become 'high' and stay 'high'. Component 'X' needs to send out one pulse when it's input is set high.

Can anybody tell me what component to use for X?

Thanks :-)