Captured Sound Waves Could Power Cell Phones While You Talk
Sound-to-electricity generators in phones could turn voices into volts; this guy isn't shouting, his battery is just low.
CREDIT: © Yuri Arcurs | Dreamstime.com
Rather than draining the battery, blabbing on your cell phone someday could be a way to keep the mobile device charged up, according to a new study.
The study's authors describe how to turn the vibrations in speech to electricity courtesy of a tiny generator that can fit inside of a mobile device. Besides powering cell phones, the researchers propose that sound-to-electricity generators could also be placed in walls along highways to harvest energy from the noise of passing vehicles.
The trick to capturing this energy is piezoelectricity , which is when mechanical strain produces a charge.
Piezoelectricity has been a hot area of technology research in recent years. Concepts have included clothes enmeshed with fine, flexing wires that could put the motion of their wearers' to good use.
Similarly, the researchers reasoned, the vibrations from voices could be transmitted through a material in handsets to recoup some of the energy that for now just keeps a conversation going.
"The sound (noise or even music) that always exists in our everyday life and environments has been overlooked as a source for piezoelectric power generation despite the fact that it is a form of mechanical energy," the authors wrote last month in Advanced Materials.
To this end, the Korean scientists constructed a tiny electrode sandwich using wires of zinc oxide, an ingredient commonly found in suntan lotion.
They then subjected this nanogenerator to 100 decibels of racket – about that of a lawnmower or a subway car and twice that of a normal conversation.
Even in this considerable din, the device generated only about 50 millivolts of electrical output – enough to slowly charge a cell phone but not enough to have it remain in standby mode.
Nevertheless, the researchers believe they have a promising approach for an awfully convenient means of energizing a cell phone in the future – actually using it rather than having to plug it into the wall.
On the downside, however, those people who shout into their phones might have a good excuse: "my battery's low."