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This is fake. They got some gullible reporters to plug their phones into black boxes, which are supposedly receiving power. In reality, those boxes contain sens

This is fake. They got some gullible reporters to plug their phones into black boxes, which are supposedly receiving power. In reality, those boxes contain sensors to tell them when to pretend to receive power, plus batteries. If it were real, they would've given the demo to someone with technical sophistication. They wouldn'tve bothered taking a trip to a phone store, since all the observers already had their own phones. And, also, the laws of physics would be slightly different. But this scam isn't aimed at us. It's aimed at investors, who will never read this Hacker News thread, or any other thread where smart people are around to debunk it. Because if they did read that sort of thing, they wouldn't be an investor.

icelancer 9y ago
This is not fake. It is real. It is, however, put on display in a such a way that masks all the very real limitations on such technology. The sensors + batteries in the box is an absurd claim.
- jacquesm 9y ago
  > The sensors + batteries in the box is an absurd claim. No more absurd than that uBeam will deliver meaningful power using ultrasound. So if they are going to show a demo that does what they claimed originally then the contents of the box would definitely be subject to scrutiny. I've had a really nice rigged demo tried on me during a tech DD once and that tech was a lot more believable than what is on display here so some skepticism is warranted. Also note that the 'charging' indicator lighting up is mostly a function of applied voltage and not so much of the current flowing, even a tiny bit of current would do the trick. I should measure with one of the phones here and a variable power supply what it takes to get that indicator to come on but I know it can't be much because a small solar cell will do it too. http://www.instructables.com/id/How-20-Make-a-Solar-Cell-Phone-Charger/ http://www.instructables.com/id/How-20-Make-a-Solar-Cell-Pho... (Conveniently does not mention how much current flows but that's right in the spirit of tfa.)
tmh79 9y ago
While I agree with you that this demo is suspect, I think your comment would be more useful if you backed it up with some of the physics/engineering principles that support your point of view.
- daveguy 9y ago
  Here are osha safety guidelines for ultrasonic sound: https://www.osha.gov/dts/osta/otm/new_noise/appendixc.pdf https://www.osha.gov/dts/osta/otm/new_noise/appendixc.pdf tldr: Maximum 115 dB Here is a calculator to convert decibels to watts: http://www.sengpielaudio.com/calculator-soundlevel.htm http://www.sengpielaudio.com/calculator-soundlevel.htm tldr: ~0.3 watts per square meter Surface area of a google pixel: 14.3cm x 6.95cm = 0.01 square meters Therefore approximately 0.003 watts over the surface area of a phone at safe volumes. At 5v that's 0.6 mA. Barely enough to light up LEDs. It looks like they're working with larger holders, say 20cm x 20cm that's 0.04 sq meters or 2.4 mA at 5v. It takes about 10 mA to trip the "charging" indicator on an android phone: http://liesandstartuppr.blogspot.com/2017/06/what-does-it-take-to-switch-phone.html http://liesandstartuppr.blogspot.com/2017/06/what-does-it-ta... This is based on the raw power of the sound waves. There will be inefficiency converting from sound to electricity, so they are probably dealing with greater than 115 dB sound at the phone. They are probably just barely tripping the charge sensor for 100 hour charge times. If they are charging significantly then they are working with very excessive excessive sound levels (>125 dB). Given imperfect transducers for 100% conversion of sound to electricity and the above dimensions they would have to be working with > 122 dB sound at the phone for 10 mA charge current. So, it's either a scam or it's not safe. Jamming that much air pressure in a small space will cause problems and will probably be inefficient. Sound is not a laser. You can beam form it, it just won't be as tight as a laser, or even a flashlight. You can't expect clean narrow patterns within a 45 degree cone from the source. There will be high and low intensity interference patterns. You can even see it in the demo.

icelancer 9y ago

This is not fake. It is real. It is, however, put on display in a such a way that masks all the very real limitations on such technology. The sensors + batteries in the box is an absurd claim.

jacquesm 9y ago
> The sensors + batteries in the box is an absurd claim. No more absurd than that uBeam will deliver meaningful power using ultrasound. So if they are going to show a demo that does what they claimed originally then the contents of the box would definitely be subject to scrutiny. I've had a really nice rigged demo tried on me during a tech DD once and that tech was a lot more believable than what is on display here so some skepticism is warranted. Also note that the 'charging' indicator lighting up is mostly a function of applied voltage and not so much of the current flowing, even a tiny bit of current would do the trick. I should measure with one of the phones here and a variable power supply what it takes to get that indicator to come on but I know it can't be much because a small solar cell will do it too. http://www.instructables.com/id/How-20-Make-a-Solar-Cell-Phone-Charger/ http://www.instructables.com/id/How-20-Make-a-Solar-Cell-Pho... (Conveniently does not mention how much current flows but that's right in the spirit of tfa.)

tmh79 9y ago

While I agree with you that this demo is suspect, I think your comment would be more useful if you backed it up with some of the physics/engineering principles that support your point of view.

daveguy 9y ago
Here are osha safety guidelines for ultrasonic sound: https://www.osha.gov/dts/osta/otm/new_noise/appendixc.pdf https://www.osha.gov/dts/osta/otm/new_noise/appendixc.pdf tldr: Maximum 115 dB Here is a calculator to convert decibels to watts: http://www.sengpielaudio.com/calculator-soundlevel.htm http://www.sengpielaudio.com/calculator-soundlevel.htm tldr: ~0.3 watts per square meter Surface area of a google pixel: 14.3cm x 6.95cm = 0.01 square meters Therefore approximately 0.003 watts over the surface area of a phone at safe volumes. At 5v that's 0.6 mA. Barely enough to light up LEDs. It looks like they're working with larger holders, say 20cm x 20cm that's 0.04 sq meters or 2.4 mA at 5v. It takes about 10 mA to trip the "charging" indicator on an android phone: http://liesandstartuppr.blogspot.com/2017/06/what-does-it-take-to-switch-phone.html http://liesandstartuppr.blogspot.com/2017/06/what-does-it-ta... This is based on the raw power of the sound waves. There will be inefficiency converting from sound to electricity, so they are probably dealing with greater than 115 dB sound at the phone. They are probably just barely tripping the charge sensor for 100 hour charge times. If they are charging significantly then they are working with very excessive excessive sound levels (>125 dB). Given imperfect transducers for 100% conversion of sound to electricity and the above dimensions they would have to be working with > 122 dB sound at the phone for 10 mA charge current. So, it's either a scam or it's not safe. Jamming that much air pressure in a small space will cause problems and will probably be inefficient. Sound is not a laser. You can beam form it, it just won't be as tight as a laser, or even a flashlight. You can't expect clean narrow patterns within a 45 degree cone from the source. There will be high and low intensity interference patterns. You can even see it in the demo.