What if you could charge your smartphone or iPod without wires or even an electrical connection? Recent developments in electrical engineering could make energy scavenging a reality.
Did you know that even when standing in the middle of your yard, a city park, or an empty room, there is energy all around you? Radio and television transmitters, cell phone networks and satellite communications systems all produces small amounts of ambient energy that flows invisibly through the air every second of the day.
According to two scientists at the Georgia Institute of Technology, this unused ambient energy could be put to use powering small electronics without the need for wires or an electrical outlet.
"There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it," said Manos Tentzeris, a professor in the Georgia Tech School of Electrical and Computer Engineering who is leading the research. "We are using an ultra-wideband antenna that lets us exploit a variety of signals in different frequency ranges, giving us greatly increased power-gathering capability."
Scavenging experiments utilizing TV bands have already yielded power amounting to hundreds of microwatts, and multi-band systems are expected to generate one milliwatt or more, but Tentzeris and his team have finally developed a device that can harness this energy and use it to power wireless sensors, microprocessors and communications chips. And the best part is that just like technology that harvests solar energy, this devices is made with an ink jet printer.
The researchers using the printers to combine sensors, antennas and energy-scavenging capabilities on paper or flexible polymers. The resulting self-powered wireless sensors could be used for chemical, biological, heat and stress sensing for defense and industry; radio-frequency identification (RFID) tagging for manufacturing and shipping, and monitoring tasks in many fields including communications and power usage.
The team says the scavenging device could be used by itself or in tandem with other generating technologies. For example, scavenged energy could assist a solar element to charge a battery during the day. At night, when solar cells don't provide power, scavenged energy would continue to increase the battery charge or would prevent discharging.
Utilizing ambient electromagnetic energy could also provide a form of system backup. If a battery or a solar-collector/battery package failed completely, scavenged energy could allow the system to transmit a wireless distress signal while also potentially maintaining critical functionalities.
images via Georgia Tech