Digi-key has little piezo LDT vibration sensors, one has a
little weight on it to help things along.  US$ 0.75-$1.00
each.

alice

> At 09:11 PM 5/30/01 +0200, you wrote:
> >you can use a mercury switch or a really small metall ball
> switcth..(personally I woulnd't use mercury, because of the environment)
>
> Ah, the inexpensive on/off kind used in security systems uses two precious
> metal contacts, one fixed
> and one flexible, with a weight on the flexible one. Vibration causes a
> momentary break
> in the circuit. You can ajust the spring force for more or less senstivity,
> and less or more
> reliability. These are made by the container load.
>
> You can also use piezo sensors that are made for the purpose. I did a test
> rig for destructive
> testing of crushing of the platinum-plated ceramic cores used in an
> automotive application using
> that kind of $ensor, IIRC they wanted US$100 for the _cable_ alone.
>
> Best regards,
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