timed open circuit on normally closed

Hi guys, first post so be gentle :P I think this is the right area for this, but anyway: I've got a reverse beeper warning in my IS200, I'm wondering if there is a way I can time it off. I.e. it currently remains permanently powered until it comes out of reverse again, and I'd like it to stop beeping after a few seconds, regardless of power through the circuit still. As far as I am aware it is a simple power, buzzer, switch, ground circuit so it shouldn't be that complex to install anything inline. Am I right in thinking that clever use of a relay and capacitors might be able to do this? Or would a locking relay or bi-metallic strip be a better option? Any help would be greatly appreciated. Thanks

Use a timer relay simplest way, e.g. DEI 528t or a Velleman kit. Simpler and more reliable.Test before boxing up.

MMM Thats definitely worth looking into. After a bit of googling I think the term I should be using is Auto-off :P Why that didn't occur to me earlier I don't know, but hey, live and learn. I did some reading about the 555 timer, can that be used effectively in this situation?

Yes, both the above kits use a 556, the 528t is ready made so far simpler.Test before boxing up.

Just had a play with a circuit builder, would this not work with the correctly sized resistor and capacitor? As the reverse switch is closed, the capacitor will begin to charge, closing the relay and allowing current to flow to the speaker, and eventually closing the relay when fully charged after a few seconds, then as the reverse switch is opened again, the capacitor will discharge, closing the relay, but the speaker wont sound as the reverse switch is open now. Is this correct? I don't particularly want to mess with timer circuits for something like this :P

Very much so, I generally use pre made because they're more reliable.Test before boxing up.

Excellent, just had another play, I think I'm going to be working in a confined space, so a relay might not work as well. Will the circuit on the right do the same thing?

Not sure but have you looked at RS for mini power relays PCB mount? 1-5 amp are very small and I'll guarantee the buzzer draws about 1/2 amp or less.Test before boxing up.

I haven't no, I'll have a look and see what it comes up with, thanks

Q1 needs to be NPN. It won't be a sharp turnoff, but IMO it's better than relay chatter.