那些永久性裝置的關鍵特性，就是他們能無限期執行任務，而且使用者不用擔心換電池的問題。在美國加州嵌入式系統會議(Embedded Systems Conference)期間的一場能量採集技術座談會上，與會者針對二十年來該技術的發展歷程分享了不少意見；多數人都認為，無線與低功耗電子元件的發展，以及感測器、MEMS等元件的演進，是對今日能量採集技術造成基礎性變革的因素。
德州儀器(TI)的工程經理Dave Freeman表示，低功耗電子元件與無線技術的發展，讓能量採集技術打開在許多應用領域的「能見度」。伊利諾大學(University of Illinois)副教授Patrick Chapman也同意，由於無線通訊元件的功耗越來越低，是讓小型能量採集裝置終於找到「用武之地」的主要因素。
(參考原文：Advancements in wireless, sensors and MEMs are set to change energy harvesting ，by Junko Yoshida)
SAN JOSE, Calif. — Technologies that harvest or scavenge energy have been in development for the last 20 years. They enable so-called "perpetual devices" to monitor buildings, to gauge tools and machines installed in inaccessible places, or to sense structural integrity or movement.
The key to such perpetual devices is that they perform these tasks indefinitely, thereby eliminating the need to replace batteries. Energy harvesting is increasingly becoming a hot topic. But "what has really changed energy harvesting in the last two decades?" asked Patrick Mannion, editorial director of TechOnline, who moderated the energy harvesting panel at Embedded Systems Conference on Tuesday (March 31).
The answer, in sum, is a confluence of the development of wireless and lower power electronics, along with advancements in sensors and MEMS. The result is a combination of factors that is fundamentally changing today's energy-harvesting market.
The development of low-power electronics and wireless technologies made it "viable" to use harvested energy for a number of applications, said Dave Freeman, engineering manager at Texas Instruments.
Patrick Chapman, associate professor at University of Illinois, agreed. "The power of wireless communication devices has become so low that we can finally start doing something about small, harvested energy," he said.
Eugene You, application engineering manager at EnOcean, added, "Don't forget the price of wireless devices." With a steady decrease in the cost of wireless devices, he said, "We can now put [perpetual devices] everywhere for sending data wirelessly, and forget about it."
Nonetheless, you still need a power storage device, said Steve Grady, vice president of marketing at Cymbet Corp. Some systems are required to occasionally handle a large burst of energy. If you can store energy, such as in a thin-film battery Cymbet is developing, "you can respond to it faster," Grady added. And that energy storage device "needs to hold charge long-term."
Every new technology often needs a hot mass market that can help lower the cost of the technology and push it to a broadly penetrated mainstream technology. What's the killer app for energy harvesting technology?
"Wireless is the killer app for energy harvesting," said Keith Abate, director of business development, at Perpetuum.
TI's Freeman agreed. "Wireless sensor networks " used in so many different applications " will drive the acceptance of energy harvesting," he explained.
Cymbet's Grady chooses smart buildings and intelligent monitoring as killer apps. "I see the stimulus package helping to create a lot of access to energy harvesting," he added.
A new wrinkle is that MEMS sensors themselves may become energy harvesting devices, said the University of Illinois' Chapman. Further, "Things like medical sensor devices that could be flown into blood could be also killer apps, for example," he added.
The Holy Grail for energy harvesting applications lies in the use of the technology when combined with wireless and sensors.
With the help of energy harvesting devices, one can collect data, process it, transport it and analyze it. What's lacking is interoperability among such data.
The use of Internet Protocols is ideal for that purpose, said Cymbet's Grady, so that data collected from different wireless sensor networks can be pulled together. The problem of using IP is that it's power-hungry when used in wireless devices. Further, if using IPs, one needs a whole new address space for billions of sensors.
Developing the standard protocol for a variety of wireless sensor networks is still "a few years off," said Grady.
One can use a variety of wireless technologies, including WiFi, Bluetooth, Zigbee or others. But without interoperability, a killer wireless/sensor application for energy is hardly a sure thing, Grady acknowledged.
