How can I make a small earthquake simulator?

Question

I'd liek to build a 1m x 1m x 2m tall wooden box which vibrates like a small earthquake when someone stands inside. I've been looking at all sorts of motors, and even thinking of modifying electric hammering drills, which would then be sandwiched between a sheet of metal (attached to floor) and a wooden floor on top.

Does anyone have any other suggestions? Anyone built an earthquake simulator before, or seen how to build one online?!!

Thanks in advance!!

Answer 1

Due to stability and momentum problems, I would opt for static sides and rely on a loose, moving floor for the simulation.

The floor could be mounted on 4 compression springs and to the under-floor base, two shafts installed, each with a steel cam blank mounted at one end.

The two shafts would be linked by an 'A' belt and a further 'A' belt to a drive shaft behind the 1m square.

The two cam blanks(mild steel discs) would be drilled and each linked to the underside of the floor via a short piece of steel, angle bracket and two HS bolts with lock nuts. This would form an dual eccentric drive to provide vertical movement.

Motor speed would be a problem, which is why I opted for an auxiliary drive shaft at the rear instead of a direct connection to a motor. (1425rpm would be much to fast).

Assuming that your budget does not run to low revving motor and speed controller, experiment directly connecting (using the chuck) a fairly powerful variable speed electric drill to the drive shaft and see how it behaves. Use of springs will have reduced the power requirement so the 1/2HP effective output from an electric drill may be sufficient.

Good Luck.

Answer 2

Use sub-woofers ... get 'em cheap as part of 2.1 PC speaker set-up & bolt them direct to the floor