Haven't you had moments (weddings, reunions, road trips) when you've wished for a sort of diagrammatic overlay on life? Just a few names or directions projected over vaguely familiar faces or places?
As it happens, the technology to realize that vision is already in the works, in the form of contact lenses that function as computer screens. But as the August Smithsonian points out, this type of gadget faces a last major challenge: power.
The devices pack so much gadgetry into such tiny spaces that even the smallest batteries would be too bulky, never mind the inconvenience (and potential discomfort) of replacing them.
Now, collaborators at the Defense Advanced Research Projects Agency and MIT are looking to the body itself - its thermal and kinetic energy - as a source of power, and that's proving to be a classic engineering challenge: Where do you get the energy? How do you make the most of it? How do do you direct it efficiently to the device that needs it?
In the case of harnessing vibrations, [researchers] use piezoelectric materials, which produce an electric current when subjected to mechanical pressure. For energy scavenging, ordinary vibrations caused by walking or even just nodding your head might stimulate a piezo material to generate electricity, which is then converted into the direct current (DC) used by electronics, stored in solid-state capacitors and discharged when needed. This entire apparatus fits on a chip no larger than a few square millimeters. Small embedded devices could be directly built onto the chip, or the chip could transmit energy wirelessly to nearby devices. The chip could also use thermoelectric materials, which produce an electric current when exposed to two different temperatures-such as body heat and the (usually) cooler air around us.
In addition to being conceptually awesome, body-powered embedded devices circumvent a growing problem: the projected tripling by 2030 of energy consumption attributable to personal gadgets.