What makes the "clicky clicky" noise when you switch on your turn signal?

I was planning on making a "How to Make a Suspicious Object" Instructable, but I'm at a loss for making a loud tick-tock noise. I haven't been able to find a clock with a tick loud enough to be noticeably audible through the box.

Perhaps I should elaborate a little on my goal... I want to create a couple of very questionable-looking objects. Think cardboard box wrapped in electrical tape with wires sticking out from it. But that's just the start. Of course we'll need a clock-like tick, and perhaps even a count-down timer! Some tilt-sensitive vibrating motors, etc. :P

As of right now, it'll just be for fun, some electronics experience, some laughs, etc.

Which leads me to: What makes the clicky-clicky noise when you flip on your turn-signal?

Update:
Darn! Someone beat me to it! Apparently Junkfunnel Labs is way ahead of me. Here's the video.

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lemonie10 years ago
You're talking about an auto indicator device? Inside these is a bimetallic strip, with some wire wrapped around it. When current flows through this (to your lights) the strip is heated and bends. Being part of the circuit, it switches your lights and the heating element off. Then the strip cools down and reverts to it's original position and the process repeats. The clicking is the strip making / breaking contact. Since heating is proportional to current, these click at a different speed when one of your bulbs is 'out'. L
And I always thought it was a loud relay or contactor relay :P
me too i gues i learned something today
I just replaced the bimetallic strip flasher in my car with a modern relay type. The nice thing (or is it a flaw?) of the new flasher is that it doesn't stop working if one bulb burns out. Until it actually happens, I won't know how it will operate differently with less current.
lemonie LasVegas10 years ago
The bimetallic types don't stop working, they just go faster (since the strip doesn't get as hot and bend so far, and it cools quicker).
LasVegas lemonie10 years ago
I took my bad one apart. It failed because the contact on the strip built up too much carbon as a result of arching. Had I cleaned it , I'm sure it would have worked again.
carbon (author)  lemonie10 years ago
Huh. Any idea what kind of current we're talking here? Sounds a bit finicky if all I want is a clicking noise. Maybe I'll just have a CD player and some speakers. :P
lemonie carbon10 years ago
Think 12v maybe you'r looking at ~1A+? There is an Altoids / CD lens assembly 'beating heart' instructable on here somewhere, see if you can find that. Or a clockwork clock? L
CowGuy10 years ago
I say still make an instructable the site doesn't show how they made it.
carbon (author)  CowGuy10 years ago
Oh, of course I will. It's just that I thought I might have had an original idea...
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