More Unusual functions of cheap parts

I built a robotic vehicle with unusual components:

1. Two drive motors are cheap electric drills from K-mart at each
2. Swivel for castoring rear wheel is from old hard drive, very smooth
3. Body of car is an old plastic toy wagon, very strong
4. Tire for castoring rear wheel is model airplane tire
5. Two tires for drives are plastic timing gears, the cogs dig into carpet nicely

I modified an old TV cart and use it as a computer station. Looks odd, but works well.

The drive coil and the magnet from an old hard drive make a great vibration sensor. I hung it from the basement ceiling and attached a one yard bar to it with a weight attached. Tremors in the basement beams generate a signal in the drive coil. Would it make a good seismic detector if it was magnetically damped, the correct pendulum length and weight attached, and proper signal conditioning added?

Al