You cannot do what you want.

The mass sitting there has potential energy, which cannot be converted to other forms of energy. You can measure it though. Any such measurement devices use outside power, or measure displacement of a known constant.

To make use of that energy you have to let the mass move as kinetic energy, which you can, in theory, capture (whether there is enough energy to be worthwhile to capture is another matter).

In otherwise, if the force moves, you can use that movement to generate electricity.

You could put a bridge on great big plungers that would compress, thus 'move' when every semi drove over it, and generate electricity from that. But the energy would come directly from the semi and each one would be required to produce that much more energy to drive across your bridge.

Just like you walking across a trampoline requires more energy than a sidewalk.

The US military did research into installing piezoelectric generators into the boots of the infantry. The theory was that using the piezoelectric effect (the ability of certain materials such as quarts to produce an electric charge when highly compressed) marching soldiers might be able to provide enough energy to power an integrated personal computer system. However, the weight of the equipment strapped to their feet proved to be impractical. Maybe the same theory could be applied to the shocks of a car, so that every pot-hole helps recharge the battery?

electricity from walking is pretty similar.

http://www.damninteresting.com/?p=78#more-78

Incidentally, di is a great site, too.

electricity from walking is pretty similar.

http://www.damninteresting.com/?p=78#more-78

Incidentally, di is a great site, too.