WirelessPowerTransfer
Latest
Stanford researchers make heart implant powered by radio waves, put batteries out of a job
Batteries used to be the only way to power implantable gadgets, but additional surgeries are needed to replace the power packs once their juice runs out -- a less-than-ideal solution for patients. Recent discoveries, however, have such medgadgets being powered by photons, hip hop and now high-frequency radio waves. Electrical engineers at Stanford built a cardiac device that uses a combination of inductive and radiative transmission of power, at about 1.7 billion cycles per second, to its coiled receiving antenna. Previous prevailing opinion held that the high frequencies needed for wireless power delivery couldn't penetrate the human body deep enough, and the lower frequencies that would do the trick require antennas too large to work as implants. That conundrum was solved by getting the high-frequency signals to penetrate deeper using alternating waves of electric and magnetic fields. That allowed a 10x increase in power delivery -- up to 50 microwatts to a millimeter radius antenna coil -- to an implant five centimeters below the skin. That antenna also was also designed to pull power regardless of its orientation, making it ideal for applications inside always-moving human bodies. Of course, the implant's really just a proof-of-concept at this stage, but hopefully it won't be long before battery powered implants go the way of the dodo TouchPad.
Microsoft earns patent for claimed wireless charging improvement, pad with info screen
Device makers are bent on bringing us inductive charging, and Redmond has joined the fray with a recently allotted patent that describes all kinds of tech that could make it work better. For the charging itself, a trick is proposed that's similar to one we've seen before -- careful matching of the resonant frequency of charger and device. That would amplify efficiency and allow more than one device to be charged at a time. To make it easier to use, a pressure sensor could detect if a device was on the pad, with different parts of the pad allocated for smartphones or tablets, for instance. The patent also proposes a display placed opposite the charger to give it another use when it's not juicing, which would be determined by a gyro to sense which side was facing up. Of course, a lot of patents are whimsical things, which never amount to anything -- but judging by the detail in this one, Microsoft may have something more concrete in mind.
Scientists tweak wireless power transfer, Tesla nods happily in his grave
Wireless charging may be all the rage these days, but actually beaming electricity -- as sketched above by the man Tesla himself -- still has some snags. North Carolina State U researchers have found a way to possibly vanquish the biggest problem: the difficulty of exactly matching resonant frequencies to amplify current. If external factors like temperature change the tuning of a transmitter even slightly then power drops will occur, but circuitry developed by the NC State scientists would allow receivers to detect these changes and automatically re-tune themselves to match. This could make for more potent car and device charging in the future and, if they stretch the distances a bit, maybe we'll finally get the wire-free utopia Nikola dreamed up 120 years ago.
