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I am skeptical of the claimed safety of uBeam. The FDA does not advocate the safety of ultrasound. From the article: "Was it safe? Well … for starters it is ju

I am skeptical of the claimed safety of uBeam. The FDA does not advocate the safety of ultrasound. From the article: "Was it safe? Well … for starters it is just an inaudible soundwave being transferred – as in the kind also used for women during pregnancy." From the FDA: "Even though there are no known risks of ultrasound imaging, it can produce effects on the body. When ultrasound enters the body, it heats the tissues slightly. In some cases, it can also produce small pockets of gas in body fluids or tissues (cavitation). The long-term effects of tissue heating and cavitation are not known. Because of the particular concern for fetal exposures, national and international organizations have advocated prudent use of ultrasound imaging. Furthermore, the use of diagnostic ultrasound for non-medical purposes such as fetal keepsake videos has been discouraged."[0] [0]http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/ucm115357.htm http://www.fda.gov/Radiation-EmittingProducts/RadiationEmitt...

ekianjo 12y ago
The whole article is making optimistic assumptions about just everything. Is that actually a PR piece?
- headgasket 12y ago
  I think the distinction of what is a PR piece and what is not has kind of blurred dramatically recently, dont you? It's an interesting concept to beam power via ultrasound, but it sure sounds optimistic at any realistic distance, or to make it as prevalent as wifi. Maybe there's a killer use case only the initiated (VCs and management) know of of? Otherwise it seems like a long shot for 10M.
- source99 12y ago
  To me this seems more potent than a typical paid PR piece. This seems like the last person to invest just realized they are holding the bag and if they believe hard enough they can pass it on.
- judk 12y ago
  It's written by an investor, right? If so, yes it's marketing.
aganders3 12y ago
That quote from the FDA is referring to ultrasound imaging, which is performed with transducers in direct contact with the body. Even in those instances, ultrasound is regarded as one of the safest medical imaging techniques. Nonetheless, while I suspect this technology is safe, I agree they shouldn't hand-wave over that aspect.
- Rizz 12y ago
  Medical ultrasound imaging uses far higher frequencies than the patents for uBeam claim, so they can't be compared. And even medical ultrasound isn't fully safe, there are some indications of brain damage in mouse models after long exposure to ultrasound.
harshreality 12y ago
5W of ultrasound focused on something the size of a phone (roughly .01 m^2) is at least 500 W/m^2. That's 147 dB, I think? (10 * log(500 (W/m^2) / 10^(-12) (W/m^2))/log(10)) A giant 0.1 m^2 tablet charging at 12W (120 W/m^2) needs only a 140 dB field. A watch, which might need 1W but with a cross section of more like .001 m^2 (for 1000 W/m^2), needs a 150 dB field. If something intercepts the beam at 1m instead of the 3m the device is charging at, the cross section of the beam is about 1/3 by 1/3 the final cross section, which since it has to have the same energy (actually would need more to compensate for attenuation through air) would be nearly a 10dB increase? Is 160dB of ultrasound (at 40kHz or 110 kHz) safe... for a few seconds? for a few minutes? a few seconds of exposure, daily? To your eardrum? To your eyes? Higher energies needed if the phone isn't perfectly oriented. Worse case is small edge-on orientation to the transmitter. Higher energies needed for less than 100% transducer efficiency, and I don't know what kind of engineering magic they've done for the transducer but what percentage of the energy could a thin skin over a device possibly convert? 80%? 50%? The beam could be 170dB, or more. I want to believe, but this is too sketchy without more information. Large companies have been conned out of millions by small teams peddling snake oil. I'd first want to see it demonstrated with nothing but the transmitter plugged into a socket (through a power meter), a phone at a known, low battery level, and nothing else with wires or metal in the room. Then I'd like to see a test of the transmitter aimed (from above) at a glass of water with a visible thermometer, to see what it does to water.
xkcd-sucks 12y ago
I use "inaudible soundwaves" on a daily basis to turn cells into formless goo. It's so destructive that we generally only use it for really tough things like bacteria. Ultrasound is also really good at chopping up DNA into little fragments. Granted, this is for 10s-100s of watts, but I still avoid putting my fingers into the low power sonic bath... cargo-cult superstition dies hard.

ekianjo 12y ago

The whole article is making optimistic assumptions about just everything. Is that actually a PR piece?

headgasket 12y ago
I think the distinction of what is a PR piece and what is not has kind of blurred dramatically recently, dont you? It's an interesting concept to beam power via ultrasound, but it sure sounds optimistic at any realistic distance, or to make it as prevalent as wifi. Maybe there's a killer use case only the initiated (VCs and management) know of of? Otherwise it seems like a long shot for 10M.
source99 12y ago
To me this seems more potent than a typical paid PR piece. This seems like the last person to invest just realized they are holding the bag and if they believe hard enough they can pass it on.
judk 12y ago
It's written by an investor, right? If so, yes it's marketing.

aganders3 12y ago

That quote from the FDA is referring to ultrasound imaging, which is performed with transducers in direct contact with the body. Even in those instances, ultrasound is regarded as one of the safest medical imaging techniques. Nonetheless, while I suspect this technology is safe, I agree they shouldn't hand-wave over that aspect.

Rizz 12y ago
Medical ultrasound imaging uses far higher frequencies than the patents for uBeam claim, so they can't be compared. And even medical ultrasound isn't fully safe, there are some indications of brain damage in mouse models after long exposure to ultrasound.

harshreality 12y ago

5W of ultrasound focused on something the size of a phone (roughly .01 m^2) is at least 500 W/m^2. That's 147 dB, I think? (10 * log(500 (W/m^2) / 10^(-12) (W/m^2))/log(10)) A giant 0.1 m^2 tablet charging at 12W (120 W/m^2) needs only a 140 dB field. A watch, which might need 1W but with a cross section of more like .001 m^2 (for 1000 W/m^2), needs a 150 dB field. If something intercepts the beam at 1m instead of the 3m the device is charging at, the cross section of the beam is about 1/3 by 1/3 the final cross section, which since it has to have the same energy (actually would need more to compensate for attenuation through air) would be nearly a 10dB increase? Is 160dB of ultrasound (at 40kHz or 110 kHz) safe... for a few seconds? for a few minutes? a few seconds of exposure, daily? To your eardrum? To your eyes? Higher energies needed if the phone isn't perfectly oriented. Worse case is small edge-on orientation to the transmitter. Higher energies needed for less than 100% transducer efficiency, and I don't know what kind of engineering magic they've done for the transducer but what percentage of the energy could a thin skin over a device possibly convert? 80%? 50%? The beam could be 170dB, or more. I want to believe, but this is too sketchy without more information. Large companies have been conned out of millions by small teams peddling snake oil. I'd first want to see it demonstrated with nothing but the transmitter plugged into a socket (through a power meter), a phone at a known, low battery level, and nothing else with wires or metal in the room. Then I'd like to see a test of the transmitter aimed (from above) at a glass of water with a visible thermometer, to see what it does to water.

xkcd-sucks 12y ago

I use "inaudible soundwaves" on a daily basis to turn cells into formless goo. It's so destructive that we generally only use it for really tough things like bacteria. Ultrasound is also really good at chopping up DNA into little fragments. Granted, this is for 10s-100s of watts, but I still avoid putting my fingers into the low power sonic bath... cargo-cult superstition dies hard.