Wireless power transmission using acoustically coupled transducers

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BasicHIFI1

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#1
Sounds like a PHd thesis I know, but I was wondering about transmitting power through these transducer things we have aka speaker drivers. Outputting 30 watts at a time, a low frequency sine wave may resonate with a similar speaker on the other side of the room and tapping those speaker terminals will give a voltage and current across ? Enough to light an LED or charge a phone?
 
#2
In principle, it will work.
But (there always is a But), the conversion of electrical input power of a speaker driver is generally a few %. I don't know how efficient the conversion of acoustical energy to electrical energy is, but probably in the same range.

So you are looking at overall efficiency of a small fraction of one percent. Definitely not green!

Jan
 
#7
jan.didden said:
In principle, it will work.
But (there always is a But), the conversion of electrical input power of a speaker driver is generally a few %. I don't know how efficient the conversion of acoustical energy to electrical energy is, but probably in the same range.

So you are looking at overall efficiency of a small fraction of one percent. Definitely not green!

Jan
Click to expand...

They are designing sound- harvesting T-shirts and the like,so a little attenuation may helpt things along.

The development team behind the device estimate that when used at the festival with sound levels of around 80dB (roughly the same as a busy street), the Orange Sound Charge will generate up to 6 watt hours (W/h) of power over the course of the weekend – enough to charge two standard mobile phones or one Smartphone
Click to expand...

My idea is to

  • Get rid of batterries
  • Get rid of wires
  • Get rid of harmful radiation -maybe
 
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#9
#12
Wireless power transmission rarely gets rid of batteries - it is normally used to charge batteries.

Why do people want to get rid of wires? You need lots of wire to make the transmitters and receivers, so there is no gain in use of scarce materials.

Swapping electromagnetic induction for acoustic radiation may increase harm. It can reduce efficiency.

It seems to me that the desire for wireless charging serves two purposes:
1. it is superficially more 'modern' than placing an item in a charging cradle (although being much less efficient than a direct connection means it is actually less modern!);
2. it enables lazy people to just put the item on the charger instead of having to go to the huge trouble and difficulty of aligning the item with the charger and dropping it into the charging socket.
 
#13
Benefits of Audio Wireless Power

jan.didden said:
What you get in return may be much worse though!
Click to expand...

An interesting link: is highly technical though:

Batteryless Powering of Remote Sensors with Reversed Peltier Power Source for Ubiquitous Environments


Expanding on the following:

  • Get rid of batteries
  • Get rid of wires
  • Get rid of harmful radiation -maybe

Getting rid of batteries:
Batteries end up in landfills and damage the environment. A capacitor based power source, continously being charged by sound energy will be a great enhancement for a Bluetooth speaker, for example that gets its sound wirelessley. Batteryless power has many applications in remote controls, toys, and IoT devices.

See Battery Statistics

Getting rid of wires
The Bluetooth speaker and the 'cordless phone' are only two of the many examples of the convenience of wireless devices. Wireless power would be a huge benefit.

Get rid of harmful radiation -maybe

The WHO site says:

Cancer
Based on mixed epidemiological evidence on humans regarding an association between exposure to RF radiation from wireless phones and head cancers (glioma and acoustic neuroma), RF fields have been classified by the International Agency for Research on Cancer as possibly carcinogenic to humans (Group 2B). Studies to date provide no indication that nvironmental exposure to RF fields, such as from base stations, increases the risk of cancer or any other disease.
Click to expand...

WHO | What are the health risks associated with mobile phones and their base stations?

Of course we are not yet sure how Wi-Fi and the several radio frequencies coursing through my frame at the moment are affecting me, but I think it is somewhat of a selling point for people concerned about EM effects on the human body. Li-Fi is an alternative to data transmission using radio waves.

I guess it will widen the choice for the consumer?
 
#14
You can always sell something to some people by raising FUD or by establishing a new fashion. Acoustic energy transfer could do both, while keeping quiet about it being very wasteful of energy and resources.

Those who worry about batteries polluting the planet should not use wireless devices, including cordless phones, mobiles, tablets, electric toothbrushes, laptops, torches. I can't see this being very popular with people under 40, as their whole life revolves around such devices.
 
#16
Increased noise pollution.

Dose makes the poison. Certain radiations and frequencies may be hazardous, but the level of the RF environment is a very important factor.

But for someone concerned over RF, then having some sort of acoustic recharging won;t change the fact that what is being charged is a wireless device?
 
#17
Mythbusters was a great TV series. They are not selling anything, they are in fact trying to prove or disprove snake oil claims.

Each episode took some various claims and tested them scientifically. One such claim was that certain low audio frequencies, when applied to a human at high levels would relax the rectum and cause uncontrolled venting of the bowels.

other tests might be the classic on TV and movie screen of someone shooting at a scuba tank and the bullet exploding the tank. OR same deal on a propane tank.

I don't want to start a tangent, but look it up if you are interested.
 
#18
Total Audiophile solution

Enzo said:
Increased noise pollution.

Dose makes the poison. Certain radiations and frequencies may be hazardous, but the level of the RF environment is a very important factor.

But for someone concerned over RF, then having some sort of acoustic recharging won;t change the fact that what is being charged is a wireless device?
Click to expand...

I was hoping you would ask that, beacause there is a neat solution.

Wireless transmission of data using audio + wireless transmission of power to power the audio device. It's all audio.

Aduiophiles will love it I think. 😀

That, plus steel shielding to keep out all those dangerous TV and radio signals that are right now coursing through my biological form - I mean a body never blocked a TV signal. 😉
 
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#20
Enzo said:
Mythbusters was a great TV series. They are not selling anything, they are in fact trying to prove or disprove snake oil claims.

Each episode took some various claims and tested them scientifically. One such claim was that certain low audio frequencies, when applied to a human at high levels would relax the rectum and cause uncontrolled venting of the bowels.

other tests might be the classic on TV and movie screen of someone shooting at a scuba tank and the bullet exploding the tank. OR same deal on a propane tank.

I don't want to start a tangent, but look it up if you are interested.
Click to expand...

Mythbausters was good, we have it here on cable. Yes I have heard of that episode should be useful to watch with the happy ending and all..
 
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