Shaky Slinky Clock

You have to sneak up on this clock, hanging on the end of a slinky. If it sees you coming, it gets the shakes.

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Step 1:

Using a Roberval balance arrangement (arms in the center), it doesn't matter where I place weights as long as the left and right side have a total equal weight. Torque on the upright rod does change depending on where the weights are placed.

The clock, hanging on the slinky should be easy enough to read--but it's a slinky; it needs to bounce. To make things a little more lively, I added a PIR module to detect anyone approaching from the front. This operates a relay which turns on a shaker motor and gets the slinky moving.

The moving slinky/clock upsets my delicate balance on the arms. Rather than the traditional solution of more weight on the left, longer base on the right, guy wire on the left (I try to break traditional thinking sometimes), I decided to turn on a fan on the left. The blade "pulls" the system to the left--countering some of the wild flinging on the right. I know, it's a waste of energy, but I wanted to try the concept.