uBeam have given Techcrunch (whose owner runs CrunchFund, investors in uBeam) some new information:
http://techcrunch.com/2015/11/07/wireless-power-charger/
- uBeam has developed a high-powered air-coupled ultrasonic transducer to transmit and receive sound waves at a single frequency within the range of 45kHz to 75kHz with an output of 145dB to 155dB (or 316 W/m2 – 3kW/m2)
- uBeam can charge multiple devices simultaneously within a range of up to a 4 meter radius from a single transmitter
- uBeam is designed to deliver a minimum of 1.5 watts of electricity to smartphones, or enough to keep a phone from losing battery life even when being heavily used. Depending on the number of devices being charged simultaneously by a single transmitter, and depending on the distance of those devices to the transmitter, uBeam could charge devices at comparable rates to a wire, or faster.
- uBeam has 30-plus filed patents and 6 issued ones. At the core of its technology is the transducer the company invented, which it believes can deliver more power at the right frequency than any other.
- The patents also cover technologies including its ultrasonic phased array transmitter that includes thousands of individually addressable and controllable elements, its beamforming algorithms that can shape and steer multiple beams to multiple moving devices, and the receiver that can harvest acoustic power from these beams coming in from multiple angles.
- At launch, uBeam plans to both sell its transmitters and work with partners to install them in public places like restaurants, hotels, or cafes. It will also both sell the receiver phone cases and work with partners to loan them out to patrons of places with transmitters installed.
They claim "The information here about focused beams, frequency, and decibel level dispels many of the rumors about uBeam being too inefficient or unsafe. " with a link to this page behind 'rumors'.
They speak to Matthew O'Donnell: http://depts.washington.edu/bioe/portfolio-items/odonnell/
and Babur Hadimioglu https://www.linkedin.com/pub/babur-hadimioglu/8/799/b53
Would be fascinated to see a response from George Smith
(ps yes this is my first post, long-time lurker & youtube video watcher, first time poster)
Hey tombola. That article by Constine was both funny and a little depressing. A few weeks ago, Meredith Perry
tweeted:
"Going dark until product launch. I'll tweet about other things, but uBeam's back in the vault. No press. Heads down & focused until launch."
I admired her for making the right decision: cutting down the PR hype. But one week later, she did an on-camera interview with the BBC, including a tour of the uBeam offices:
Could we soon charge our phones through the air?And then two weeks later, that TechCrunch piece came out.
The funny thing is that TechCrunch/Constine act like they're debunking skeptics, and then go on to confirm almost everything the skeptics said. Extremely high intensities: confirmed. (In fact, uBeam now claims to have the most powerful in-air transducers ever built.) Limited to line-of-sight: confirmed. Short ranges: confirmed.
The only thing different is the frequency. I assumed 100 kHz in my calculations, while TechCrunch quotes a range of 45 to 75 kHz. A lower frequency does give uBeam a somewhat longer range. But those frequencies are well within cat hearing range (cats top out at ~80 kHz), and the longer range also means stray noise travels farther. Going back to uBeam's website, it's interesting how they brush that under the rug:
"As for animals, only bats,
cats, whales, and a few other animals could possibly detect the ultrasound that uBeam creates. We love aquatic animals but it is unlikely that uBeam would be used in the water! As for bats, these animals would hear uBeam only if it were used outside. Because uBeam uses "locked on" directional focused beams, only animals that carried a uBeam receiver would be able to "hear" the uBeam. uBeam's system will not affect pets or animals." (emphasis added)
They explain why bats and whales (mostly) aren't a problem, but appear to forget about cats. There are ~160 million cats in the US, so that's a significant oversight. It's a focused system, yes, but if it transmits 155 dB, and the goal is to keep noise leaks below "very loud" (~85 dB), the beam has to keep losses, reflections, dispersion, etc. under 0.00001%. That's just not practical.