7 ms·

Wireless Charging, at a Distance, Moves Forward for uBeam

40 points by sethbannon 12y ago

dlhavema 12y ago
nothing about the actual efficiency of the system? aren't wireless chargers pretty inefficient to start with? I for one would love this to hit mainstream and be a norm for gadgets... also, how would this affect bats or dogs?
- deleted 12y ago
  [deleted]
PaulHoule 12y ago
No mention of safety at all. A system like this is going to have at least the energy density of sunlight and that transfers enough heat into your body you can feel it. I'd be particularly concerned if the thing somehow shot a beam right at your eyes, which are the thing most vulnerable to damage from internally generated heat (i.e. microwaves)
- mcs 12y ago
  Ultrasound is widely considered safe.
  - ceejayoz 12y ago
    For diagnostics, yes. High energy focused ultrasound like you'd probably need to charge, less so. It's used to destroy tissue. https://en.wikipedia.org/wiki/High-intensity_focused_ultrasound https://en.wikipedia.org/wiki/High-intensity_focused_ultraso...
    - PaulHoule 12y ago
      I've seen demos where people use an ultrasound beam to light paper on fire, so I think the dose makes the poison.
mcs 12y ago
I hope this stays a powering technology and it doesn't attempt to become a data-channel company as well.
- WhitneyLand 12y ago
  Why not?
S_A_P 12y ago
The safety question does need to be addressed. While there isn't any solid evidence that ultrasounds are harmful to fetuses, there are some studies that into question their safety[1]. I am curious as to how much power is really being transmitted with these things. 1-http://www.midwiferytoday.com/articles/ultrasoundrodgers.asp http://www.midwiferytoday.com/articles/ultrasoundrodgers.asp
- jobu 12y ago
  I'd be curious about the effects on pets or nearby animals as well. What frequency range and power are these things running at?
- ceejayoz 12y ago
  Focused ultrasound (https://en.wikipedia.org/wiki/High-intensity_focused_ultrasound https://en.wikipedia.org/wiki/High-intensity_focused_ultraso...) can be used to destroy tissue, too. If it's not focused, the vast majority of its output is wasted energy.
SigmundA 12y ago
Yeah so ignoring the obvious absorption and occlusion issues, http://en.wikipedia.org/wiki/Inverse-square_law http://en.wikipedia.org/wiki/Inverse-square_law would make such a system exetremly inefficient at any distance right?
- duaneb 12y ago
  "Any distance" is a little much. I'd love this just to clear up wires on my desk, and at that distance I can't imagine the inverse square law would be too much of an issue. Across the house? Yea, that'd be a huge problem, I think.
  - SigmundA 12y ago
    No, I mean any distance, if it put out 10 watts at 1 inch, it would be 2.5 watts at 2 inches and .625 watts at 3 inches. You would be wasting huge amounts of power just to not have a few inches of wire. At 15ft you would need like 5000W to to get .001W at your device. This is not even thinking about the efficiency of converting electricity into sound and back again. You could focus the sound beam to improve things but then you lose the convenience of putting the device anywhere.
    - thedufer 12y ago
      Your math is a little off. Inverse square law means that every doubling in distance quarters the power, so it'd be .625W at 4 inches (or 1.111W at 3 inches).
timdierks 12y ago
I don't know a lot about specific engineering details, but a jet engine (turbofan) produces about 1 kw of sound energy [1]. A cell phone has about 75 sq. cm of area on one side. Thus, with perfect efficiency and spherical propagation, the available power to the phone for a user about 3m away would be about 0.2 watt. However, I'm skeptical that they can actually create a kilowatt of sound energy, and while you can focus the power (certainly you could do something more efficient than fully-spherical propagation), you're also going to have significant losses. All this for a charging rate that's about 1/5 of what you get from a 1 amp USB charger. [1] https://en.wikipedia.org/wiki/Acoustic_power#Table_of_selected_sound_sources https://en.wikipedia.org/wiki/Acoustic_power#Table_of_select...
- xgbi 12y ago
  Unless they are beamforming, which is highly unprobable, I think you're right.
  - sp332 12y ago
    You can do beamforming with ultrasound. http://www.ted.com/talks/woody_norris_invents_amazing_things http://www.ted.com/talks/woody_norris_invents_amazing_things The demo device was flat, like the one shown in the article.
  - timdierks 12y ago
    Beamforming would be cool and might actually allow this to work, although I don't know with what efficiency. That said, the tech just to locate the phones in space to allow the beamforming would be a significant accomplishment itself. But forming the beam or multiple beams to charge multiple devices is probably quite feasible.
    - wlesieutre 12y ago
      A possibly effective option would be sweeping the beam around and having the phone report when it hits. That should be easier than trying to accurately locate the phone first so that you can aim a beam at it. If you can also make a reasonable initial guess of it's location (to within a few degrees) you could narrow down the guess and check search area considerably.
scottlocklin 12y ago
I have a hard time expressing how unbearably stupid "wireless charging" of all kinds is, especially when it is touted as "green." The only viable use case I've been able to come up with is charging my electric toothbrush by induction, so we don't have to worry about corrosion on electrodes due to my drooling on them. Otherwise; "golly, let's radiate lots of energy into the ambient atmosphere so consumers can have a science fiction experience like they're in the Jetsons."
- erkkie 12y ago
  I charge my phone wirelessly in the car, with a magnetic wireless charger which doubles as a docking station (which automatically turns on waze/navigation). Super convenient for getting in/out of the car without needing to attach wires. Also imagine embedded medical devices.
  - johnward 12y ago
    When I had a nexus 4 I used the QI charging all the time. It's not really a must have feature but it certainly is nice to you be able to throw my phone down with out having to plug in wires.
- mcculley 12y ago
  There's plenty of use cases for devices with low power requirements that would benefit from wireless charging. Wearables, for example: watches and other little bits of technology that you wouldn't want to think twice about carrying into the shower or through the rain and requiring metallic connectors for charging them would reduce lifespan and convenience and impact the form factor.
- seanflyon 12y ago
  Wireless charging only seems unbearably stupid because you are thinking of standard, non-resonant induction. Resonant induction is much more efficient. "The fields used are predominately non-radiative" http://en.wikipedia.org/wiki/Resonant_inductive_coupling http://en.wikipedia.org/wiki/Resonant_inductive_coupling edit: The article is not referring to resonant induction or standard induction, but using ultrasound instead.
brt9957 12y ago
" the ability to charge portable electronics, like cellphones and laptops, wirelessly using ultrasound." is more exciting than finding life on other planets?
- WhitneyLand 12y ago
  The life on other planets route has less stock options.
sp332 12y ago
uBeam's "Press Kit" is a 404. http://ubeam.com/wp-content/themes/ubeam/files/presskit.zip http://ubeam.com/wp-content/themes/ubeam/files/presskit.zip
mrfusion 12y ago
Anyone know why induction can't go longer distances? Could homes be built with a giant coil in the whole attic that could then power things in the house?
- arcseco 12y ago
  I'll try to explain, forgive my peasant understanding (Single course on induction motors and actuators in Uni years ago) The limiting factor for distance of induction charging is the strength of the magnetic field per unit area or flux. Technically you could create a magnetic field large enough to pass through an entire house, I can think of two big problems with that off the bat however. First, the Magnetic field strength drops as the cube of the distance from the source. The further you are, the less effective the charging at the same power rate. As well the magnetic permeability of air is so small (µ_0 = 4π×10−7 V·s/(A·m)), this is the reason why iron cores are used in transformers as you would lose a lot of flux to the surrounding area unless it is channeled through a permeable material. The second reason is that there would be unintended effects on other conductive materials located within the magnetic field, eg computers, copper piping. The energy losses by induction charging are usually very very high when compared to charging by traditional means (Cable).

40 points by sethbannon 12y ago

nothing about the actual efficiency of the system? aren't wireless chargers pretty inefficient to start with? I for one would love this to hit mainstream and be a norm for gadgets... also, how would this affect bats or dogs?

deleted 12y ago
[deleted]

PaulHoule 12y ago

No mention of safety at all. A system like this is going to have at least the energy density of sunlight and that transfers enough heat into your body you can feel it. I'd be particularly concerned if the thing somehow shot a beam right at your eyes, which are the thing most vulnerable to damage from internally generated heat (i.e. microwaves)

mcs 12y ago
Ultrasound is widely considered safe.
- ceejayoz 12y ago
  For diagnostics, yes. High energy focused ultrasound like you'd probably need to charge, less so. It's used to destroy tissue. https://en.wikipedia.org/wiki/High-intensity_focused_ultrasound https://en.wikipedia.org/wiki/High-intensity_focused_ultraso...
  - PaulHoule 12y ago
    I've seen demos where people use an ultrasound beam to light paper on fire, so I think the dose makes the poison.

mcs 12y ago

I hope this stays a powering technology and it doesn't attempt to become a data-channel company as well.

WhitneyLand 12y ago
Why not?

S_A_P 12y ago

The safety question does need to be addressed. While there isn't any solid evidence that ultrasounds are harmful to fetuses, there are some studies that into question their safety[1]. I am curious as to how much power is really being transmitted with these things. 1-http://www.midwiferytoday.com/articles/ultrasoundrodgers.asp http://www.midwiferytoday.com/articles/ultrasoundrodgers.asp

jobu 12y ago
I'd be curious about the effects on pets or nearby animals as well. What frequency range and power are these things running at?
ceejayoz 12y ago
Focused ultrasound (https://en.wikipedia.org/wiki/High-intensity_focused_ultrasound https://en.wikipedia.org/wiki/High-intensity_focused_ultraso...) can be used to destroy tissue, too. If it's not focused, the vast majority of its output is wasted energy.

SigmundA 12y ago

Yeah so ignoring the obvious absorption and occlusion issues, http://en.wikipedia.org/wiki/Inverse-square_law http://en.wikipedia.org/wiki/Inverse-square_law would make such a system exetremly inefficient at any distance right?

duaneb 12y ago
"Any distance" is a little much. I'd love this just to clear up wires on my desk, and at that distance I can't imagine the inverse square law would be too much of an issue. Across the house? Yea, that'd be a huge problem, I think.
- SigmundA 12y ago
  No, I mean any distance, if it put out 10 watts at 1 inch, it would be 2.5 watts at 2 inches and .625 watts at 3 inches. You would be wasting huge amounts of power just to not have a few inches of wire. At 15ft you would need like 5000W to to get .001W at your device. This is not even thinking about the efficiency of converting electricity into sound and back again. You could focus the sound beam to improve things but then you lose the convenience of putting the device anywhere.
  - thedufer 12y ago
    Your math is a little off. Inverse square law means that every doubling in distance quarters the power, so it'd be .625W at 4 inches (or 1.111W at 3 inches).

timdierks 12y ago

I don't know a lot about specific engineering details, but a jet engine (turbofan) produces about 1 kw of sound energy [1]. A cell phone has about 75 sq. cm of area on one side. Thus, with perfect efficiency and spherical propagation, the available power to the phone for a user about 3m away would be about 0.2 watt. However, I'm skeptical that they can actually create a kilowatt of sound energy, and while you can focus the power (certainly you could do something more efficient than fully-spherical propagation), you're also going to have significant losses. All this for a charging rate that's about 1/5 of what you get from a 1 amp USB charger. [1] https://en.wikipedia.org/wiki/Acoustic_power#Table_of_selected_sound_sources https://en.wikipedia.org/wiki/Acoustic_power#Table_of_select...

xgbi 12y ago
Unless they are beamforming, which is highly unprobable, I think you're right.
- sp332 12y ago
  You can do beamforming with ultrasound. http://www.ted.com/talks/woody_norris_invents_amazing_things http://www.ted.com/talks/woody_norris_invents_amazing_things The demo device was flat, like the one shown in the article.
- timdierks 12y ago
  Beamforming would be cool and might actually allow this to work, although I don't know with what efficiency. That said, the tech just to locate the phones in space to allow the beamforming would be a significant accomplishment itself. But forming the beam or multiple beams to charge multiple devices is probably quite feasible.
  - wlesieutre 12y ago
    A possibly effective option would be sweeping the beam around and having the phone report when it hits. That should be easier than trying to accurately locate the phone first so that you can aim a beam at it. If you can also make a reasonable initial guess of it's location (to within a few degrees) you could narrow down the guess and check search area considerably.

scottlocklin 12y ago

I have a hard time expressing how unbearably stupid "wireless charging" of all kinds is, especially when it is touted as "green." The only viable use case I've been able to come up with is charging my electric toothbrush by induction, so we don't have to worry about corrosion on electrodes due to my drooling on them. Otherwise; "golly, let's radiate lots of energy into the ambient atmosphere so consumers can have a science fiction experience like they're in the Jetsons."

erkkie 12y ago
I charge my phone wirelessly in the car, with a magnetic wireless charger which doubles as a docking station (which automatically turns on waze/navigation). Super convenient for getting in/out of the car without needing to attach wires. Also imagine embedded medical devices.
- johnward 12y ago
  When I had a nexus 4 I used the QI charging all the time. It's not really a must have feature but it certainly is nice to you be able to throw my phone down with out having to plug in wires.
mcculley 12y ago
There's plenty of use cases for devices with low power requirements that would benefit from wireless charging. Wearables, for example: watches and other little bits of technology that you wouldn't want to think twice about carrying into the shower or through the rain and requiring metallic connectors for charging them would reduce lifespan and convenience and impact the form factor.
seanflyon 12y ago
Wireless charging only seems unbearably stupid because you are thinking of standard, non-resonant induction. Resonant induction is much more efficient. "The fields used are predominately non-radiative" http://en.wikipedia.org/wiki/Resonant_inductive_coupling http://en.wikipedia.org/wiki/Resonant_inductive_coupling edit: The article is not referring to resonant induction or standard induction, but using ultrasound instead.

brt9957 12y ago

" the ability to charge portable electronics, like cellphones and laptops, wirelessly using ultrasound." is more exciting than finding life on other planets?

WhitneyLand 12y ago
The life on other planets route has less stock options.

sp332 12y ago

uBeam's "Press Kit" is a 404. http://ubeam.com/wp-content/themes/ubeam/files/presskit.zip http://ubeam.com/wp-content/themes/ubeam/files/presskit.zip

mrfusion 12y ago

Anyone know why induction can't go longer distances? Could homes be built with a giant coil in the whole attic that could then power things in the house?

arcseco 12y ago
I'll try to explain, forgive my peasant understanding (Single course on induction motors and actuators in Uni years ago) The limiting factor for distance of induction charging is the strength of the magnetic field per unit area or flux. Technically you could create a magnetic field large enough to pass through an entire house, I can think of two big problems with that off the bat however. First, the Magnetic field strength drops as the cube of the distance from the source. The further you are, the less effective the charging at the same power rate. As well the magnetic permeability of air is so small (µ_0 = 4π×10−7 V·s/(A·m)), this is the reason why iron cores are used in transformers as you would lose a lot of flux to the surrounding area unless it is channeled through a permeable material. The second reason is that there would be unintended effects on other conductive materials located within the magnetic field, eg computers, copper piping. The energy losses by induction charging are usually very very high when compared to charging by traditional means (Cable).