The push toward low powered, energy-saving devices has been a direction the electronics industry has always pursued. The switch to low powered LED lighting is a good example of this trend. Another avenue is the development of energy harvesting, self-sufficient devices. The idea here is to use materials that display piezoelectric and triboelectric effects to convert mechanical energy into electrical energy. Piezoelectric materials generate an electrical charge when stressed mechanically, while the triboelectric effect is the buildup of charges on two dissimilar materials after they have come in contact with each other.
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Source: Phys.org