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Orange unveils the Sound Charge mobile phone charging T-shirt
MOBILE OPERATOR Orange has announced its Sound Charge T-shirt that can charge a mobile phone using sound, which it will put on trial at the Glastonbury music festival.
The 'Sound of 71' stage at this weeks event is where Orange will test prototypes of the Sound Charge T-shirts to see which acts give the best charge. The T-shirts have a special front panel to harvest sound, which it then coverts into electrical energy to charge a phone.
Andrew Pearcey, head of sponsorship at Orange said, "In a vibrant festival environment such as Glastonbury, sound is such an obvious medium that it seemed like a natural fit to use it in the development of this year's prototype."
Orange will be testing three T-shirts and putting them on show but unfortunately music lovers at the gigs won't be able to try the eco gadget out for themselves.
The A4 sized panel on the front of the shirt is made of piezoelectric film, as is usually found in hi-fi speakers. This acts like an oversized microphone so when sound waves hit it the pressure is converted into electrical charge.
The charge is fed into a reservoir battery that is able to charge various phones by using interchangeable leads. All the electrical parts are fully removable so you can still wash the garment after a grubby festival weekend.
Apparently about 80dB of sound will be experienced during a music set, which the shirt will be able to change into 6W of electricty. This is enough to charge a smartphone over the course of the weekend.
We think the idea is pretty cool, especially for music lovers, but the design will be even better if the technology is hidden away. Maybe it can be used in the home as a charging method, possibly using sound from your TV or music system. µ
Tags: Hardware
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It is just a gimmick.
In a competitive world, Orange.co.uk should concentrate on its customer service. It is an interesting development, but it is letting customers down like me who cannot get a refund for an IPAD 2 that will not unlock even though I told them in the shop I needed to use it on an Isle of Man network.
I wouldn't buy from Orange again even if this technology works.
Or working the maths the other way;
The health and safety limit of 90dB SPL is 0.001watts per square meter.
0.0000625watts in an A4 size area.
0.0000625watts assuming 50% conversion to electricity (it unlikely to be anywhere near that good)
Roughly 0.00003125watts being stored after battery charging efficiency.
Over a 48 hour period thats 2.7 joules
Which is 0.02% of the capacity of a typical mobile phone battery.
At 100dB for 48hours the user will have ringing ears, probably temporary deafness and have added 0.2% charge to thier battery.
Let me try again.
A typical mobile phone battery pack (3.6volt 1000mAh) contains about 13000 joules of energy which is 3.3 watt hours.
Allowing for charging efficiency 6 watt hours is about right to charge a mobile battery from empty to full.
Generously assuming 48 hours charging time, 26kilojoules at a steady rate is 0.15watts continuously.
At 50% conversion efficiency you need 0.3watts of acoustic power hitting 0.0625m^2
That is 4.8 watts per square meter. That corresponds to 126.8dB SPL.
The health and safety says that anyone exposed to over 90dB has to be provided with hearing protection.
126.8dB is not pleasant to be exposed to and will cause serious permanent hearing damage over a period of hours.
TDR wrote "Doing the rough maths, on a panel of 1/16 of a m2, 6 Watts seems to be in the right order of magnitude"
Either your maths or your assumptions are horribly wrong.
However if you watch the video, he actually talks about 6 Watt Hours of power. Which is presumably what the charged battery pack stores, although thats not made clear.
He doesnt say that it only take an hour to collect that much energy. Likely it takes much longer as they are talking about during a festival.
So it might take 6 hours if the average output is 1 watt..
Presumably they are talking about a level of 80dBA at the receiving end.
Loud speakers are massively inefficient - typically 5%. Piezo electric conversion however can be over 50% efficent. So not really a valid comparison.
Doing the rough maths, on a panel of 1/16 of a m2, 6 Watts seems to be in the right order of magnitude...
dB, ie decibels, are a relative measurement.
Sound is generally measured in dBA, 80dBA is about right for a concert.
The idea of getting 6watts from 80dBA of sound hitting an A4 sized area is not in accordance with reality.
Loudspeaker efficiency varys widely but a typical figure is 1watt of power applied to the loudspeaker giving 88dBA at 1 meter distance and that's with some loss as heat in the loudspeaker.
That 80dBa at 1 meter with 0.159watts into a loudspeaker and the energy is spread out over a much larger area than an A4 size collector.
How do they magically expect to get 6 watts after converting that back to electricity? It's not going to happen.
Factor in the conversion efficiency and it seems even less likely to work.