Humans move around a lot. We walk, jump and dance. So why not use all that kinetic energy? Via piezoelectric devices, that's now possible. Piezoelectricity comes from substances that generate current when they are compressed, bent or stretched. The most common application is lighting stoves (the lighter uses a piezoelectric material to generate a spark).
Now some inventors have proposed using these materials in objects that humans come into contact with and move. For example, dance floors, roads or sidewalks. Walking or even driving on the surfaces would put pressure on embedded piezoelectric materials, which could then send an electrical current out to be used to power lights.
Other ideas include embedding these materials into backpacks that would generate power for soldiers, who might be walking far from base camp. Tiny devices embedded into special knee braces could also create energy from walking.
In 2008 the East Japan Railway Company experimented with a power-generating floor, which produced enough to power ticket kiosks.