As people are leaving my house, they walk past my mailbox. When they get close, it suddenly starts banging open and closed and a bright green light streams out.
This is our first radio remote controlled effect. We modified a $20 remote controlled whoopie cushion to trigger a relay to run the mailbox. We found a point on the circuit board which changed voltage whenever the transmitter button was pressed, and amplified it to turn on the relay. The receiver and 12v power supply are in a box on the ground chained to the bush.
The salvaged geared motor and 50 watt movie projector lamp are both 12v. The transmitter turns them on and off, but a limit switch keeps them on until the wheel turns back to the closed position.
We ended up with an unintended "feature." When someone tries to open the mailbox, they twist the wheel sideways away from the limit switches' lever and this makes the motor come on. This protects the mechanism from being twisted apart, and usually scares the people away.
Lots of ordinary objects can become great startle scares by making them move suddenly as if possessed: bookshelves, a coat rack, piano, cabinet doors, bassinet, etc....
At first we stripped the gears out of a couple of motors and it looked like we'd need to buy <gasp> a bigger motor. But it occurred to me that the motor could be protected from periods of high stress by a simple fixed-friction clutch. If the wheel is stalled, the clutch allows the motor to still turn. And if the wheel is forced to turn by someone pulling on the mailbox door, the motor isn't forced to turn.
A week or so before Halloween I was in my front yard testing the mailbox. Our neighbor was driving by and saw the mailbox running. She stopped and rolled her window down. Completely off the top of my head I said, "I don't know what's going on. It screamed something about Satan and then started doing that."
She replied, "I hope it said, 'Satan begone.'"
Ever since, we've referred to her as "The Satan Lady."
(The mailbox movie looking like a Talking Heads video was entirely unintentional.)
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