The trick is to get some feedback oscillation. I once built one of these using a trusty spring from a mechanical pencil. Attach the spring to a pager motor inside a grounded aluminum housing.

When the spring hits the foil it will cause a vibration that will last for an random, but short period of time.

The challenge is calibrating the pager motor so that the spring gets a little extra kit; but shuts off most of time.

Piezo as a switch to flash an led when disturbed
An LED embedded in a small translucent item (say half the size of a pack of cards) that would flash on briefly if the object was disturbed or tipped over.
I immediately responded that a piezoelectric sensor/generator inside the object wired to an LED would do it.
However, when I tried to demonstrate this concept using a piezo buzzer I liberated from an old phone, I could only get the LED to register a dim blip when I smashed the piezo buzzer with a blunt object.
How would I ensure that a piezo sensor/generator would actually light up the LED adequately without the application of blunt force trauma.
As I mentioned, space would be an issue so no large parts, breadboards, or really complex circuitry.
I'm just trying to figure out the easiest and smallest way to accomplish this simple task.
Thanks a lot for any help you can give me!
