Radio-transmitting sensor developed by KSU engineers uses solar cells from high-end calculators to power itself.
(Credit: Kansas State University)Correction on Wednesday at 11:27 a.m. PST: A press release on which this story was partially based misidentified which NASA mission the technology will be used for. This post was updated with correct information. The energy-harvesting sensors are part of research for forthcoming Mars Scout Missions.
Engineers at Kansas State University have developed a radio with sensors and microprocessors that can transmit data and is self-sufficient when it comes to power.
The device, called by the engineers an "energy-harvesting radio," is essentially a wireless sensor with microprocessor and radio that can transfer a flash of data gathered by the sensor every few seconds.
Wireless sensors are not new; they've already been in use to monitor environmental data like river pollution and weather. Even at the consumer level, there are weather radios sold at high-tech gadget stores: people place a radio sensor on the outside of their house and read the weather report from a receiving device inside.
Only those sensors need batteries to power them. The radios being developed by the KSU researchers power themselves and their microprocessor with alternative energy. And instead of only measuring the temperature or pollution levels, these radios can be used to measure all sorts of things, such as stress on bridges.
Bill Kuhn, KSU professor of electrical and computer engineering, and Xiaohu Zhang, a graduate student in electrical engineering, are working on the project for San Diego, Calif.-based Peregrine Semiconductor.
Currently, Kuhn and Zhang are using high-end calculator solar cells to power the radio. But the radio could be powered by electrochemical, thermal, or mechanical energy, according to the researchers.
The research being developed by KSU in conjunction with NASA, the California Institute of Technology, and Peregrine will go toward developing radio sensors for use in the Mars Scout Missions.
The energy-harvesting radio also seems to be a bit of a showpiece for the communications chipmaker since the autonomous sensors happen to require the exact type of technology that Peregrine specializes in: high-speed communications integrated circuits, aka low-power radio chips. Specifically, the researchers are using Peregrine's UltraCMOS silicon-on-sapphire technology.
While they've already managed to get the system to work, Kuhn and Zhang are now refining things like range, power, and frequency. Currently, the radio sends out a burst of data from its sensor every five seconds.
But it's a delicate balancing act.
The scientists have to decide how often the radio should transmit to its receiver vs. how much power it should use, how much data it should process, and how far of a range it should be able to transmit.
Scientists from the IBM Zurich Research Lab and the Fraunhofer Institute in Berlin are working on a microchip that uses micropipes of water to cool itself, IBM announced Thursday.
The chip's components are built in a 3D stack instead of side by side on a silicon wafer.
This diagram illustrates the chip-cooling concept. Water in a cooling container (purple) is pumped through integrated spaces between the chip's layers (orange).
(Credit: IBM)Chips built in a three-dimensional stack formation offer more pathways for info to be processed and can shorten the distance chip information needs to travel by as much as 1,000 times, according to Thomas Brunschwiler, a senior engineer in the Advanced Thermal Packaging Group at the IBM Zurich Research Lab who has been working on the chip for almost two years.
The trouble is that this type of experimental chip structure also generates a large amount of heat.
To address that problem, the team has developed a cooling system consisting of micropipes of water as thin as a human hair (50 microns) that are interspersed between each chip layer.
To prevent an electrical short, the hairlike water pipes are hermetically sealed from the chip's other components first with a silicon wall and then with a layer of silicon oxide, according to Brunschwiler.
To bond the individual pipes from layer to layer without damaging other chip components, the scientists used a solder consisting of a mixture of gold and tin, which has a low melting point.
"This process enabled us to completely seal off the joints. Then we can use water, which is superior to other coolants," Brunschwiler said.
The water-cooled chip, which is intended for use in supercomputers, is 5 to 10 years away from being commercially available. "But before that, one would probably see chips with one core layer and a memory layer sitting on top that can still be cooled with (an) outside system," Brunschwiler said.
While unique in its microscopic scale, IBM's use of water to cool down the heat generated by computer processing is not novel.
Companies like IBM and Hewlett-Packard sell server racks with liquid cooling systems. Researchers at Ireland's Tyndall Institute and University of Limerick announced in March that they are working on a liquid cooling system incorporated into the packaging that encases chips. And in April, IBM announced a supercomputer that uses water alongside its processors to cool them.
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