This helps reverse that worrying decline in articles that don't use the word "asymptotic". Well done Ed. More please.
A new Apple iPhone 6 case harvests energy from the smartphone's radio transmissions and use it to charge the battery, its developers claim. Nikola Labs, which touted the product at TechCrunch Disrupt on Monday - and which was selected to pitch to the crowd there "after being selected by the techCrunch editorial team and and …
Why would Apple make a phone that used more energy than necessary to power its radios when battery life is a competitive selling point?
It would more sense for the phone to disable its own WiFi, Bluetooth and 4G when they are not being actively used - like the Stamina Mode on some Sony phones.
Given the size of this proposed case, you might as well get a cheaper 'battery case' and increase your phone's battery life 50% +.
To be most efficient, I think this case should also include a screen-facing solar panel. That way, any of the light emitted by the display can be recaptured for charging the battery.
Since all wasteful* function-related EM emissions - visible and invisible - will now have been prevented, the phone will now serve no useful purpose when inserted into the case, and so can be switched off.
If this is done, I predict that battery life could then be extended to be whatever it is when the phone is switched off.
* Since the idiot buyer of this case will only have been using the phone for yabbering to similar idiot friends, or using social media, casual gaming or dating apps, then ANY functional use of the phone can been classed as wasteful. Better to switch it off, if making it explode is not a technically or morally acceptable option.
to take off the case when you want to use Wi-Fi, Bluetooth, or LTE.
Otherwise, it sounds like a perfectly reasonable idea. Maybe the phone could also feed some power back into the grid via wireless charger during times of peak demand -- harness your phone battery for the smart grid!
The phone's entire radio usage probably doesn't use 30% of its battery life, if you pile on inefficiencies and losses, I can't imagine how you get to 30% eating all the energy from radio emissions - and you need some of that energy to get out regardless, else your phone won't communicate with anything.
To get to 30% you have to be claiming you're getting energy from nothing, surely?
Edit - just been reading engadget's article that fawns all over this thing:
The harvesting antenna and DC power-converting rectifier circuit
It's those bomb detectors in Iraq all over again.
Dr. Lee's reputation as the former chair of Ohio State's Electrical and Computer Engineering gives this seemingly kooky outfit some much-needed credibility
What reputation exactly. I see no credibility anywhere.
Oh come on, you're not giving it a chance. I'll bet they thought of the fact that they would need to recover more power than the radio uses so they likely also have a photovoltaic panel sitting over the display to capture the wasted photons to convert to electricity as well. I'm sure it's all been well thought out.
> ...and the perfect encryption scheme: any arbitrarily sized block of data encrypted as a single bit.
Well, that's possible today. All you have to do is encrypt first and then compress¹ using a sufficiently lossy algorithm. If it's lossy enough to really live up to its name, it should be capable of giving you one-bit cyphertext, which should also be quite resilient to any form of plaintext recovery attack not involving crystal balls².
What's this company's website again? I'd like to apply as their Chief Information Security Officer.
¹ The opposite as conventional norm when using non-lossy algorithms.
² Or rubber hoses.
> ...and the perfect encryption scheme: any arbitrarily sized block of data encrypted as a single bit.
Well, that's possible today. All you have to do is encrypt first and then compress¹ using a sufficiently lossy algorithm.
It's always been possible, and can be done with lossless compression.
What's difficult is encoding three arbitrary messages with a single bit.
When I'm recording video at home using a lapel mic, I've got to turn the iPhone to airport mode because it blats all over the audio track even when it's on the other side of the room. The other phones I have don't do that. *sigh* - I don't know whether to class that as a success or a fail.
>> That's a big Apple FAIL if it "blats" all over the audio track you are recording.
I've experienced this issue with every iPhone I've owned - 5 of them across different generations. I've also experienced it with quite a few other non-Apple devices.
Sure, the regulations state what they are or are not allowed to do but from what I can tell regulations are meaningless until a company gets hit with a lawsuit. Then they pay a small "settlement" fee and quietly change their product. It's not like the government actually *tests* every single device that hits the market.
Pretty much all cellular radio technologies vary the amplitude of the radio signal itself at a frequency within the audio range, so there is a finite possibility that audio equipment (particularly equipment with high gain and relatively poor screening) will be sensitive to this modulation and produce an audio output from it. Particularly so with GSM IMX.
Just... morons. Like the "smart road" which harnessed the motion of vehicles to generate electricity...
While I cannot see the above idea as being practical or cost effective, it does have the advantage that each device on a busy road would get quite a bit of energy from thousands of heavy vehicles running over it per day so is at least feasible. In contrast, the total amount of EM energy impacting on the small area of a phone case would be down in the microwatt region except from the phone it is covering, which would be a few mWh at best over an average day - way below any level that would make any significant difference to the battery's charge state.
Actually the smart road has some merit, your only capturing existing vibrations and converting to electricity, the vibrations themselves have no purpose...
Although a better idea is to have roads made from some form of solar/thermal energy capture, since they are exposed to sunlight for much of the time...
The iPhone signal harvesting is like driving a car on a treadmill..
@Ed: Surely that 30% recoup could only be re-applied to itself, not the whole initial 100% charge, so 30% of 30% is 9%, 30% of a further 9% is 2.7%, etc. The total tending to c. 142.857% (i.e. 42 odd % increase in charge time).
I suspect though the harvesting isn't that efficient, so the 30% quoted is the overall increase, so efficiency of 23 odd percent. Still high but perpetual motion (or kittehz) it isn't.
You're really thinking about this too hard.
They picked a number out of the air... Something not too small so people are interested but not too big so that they can't come up with 1000 reasons why *you're* particular phone isn't getting the 30%. It's called "marketing speak".
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It's certainly possible to pick up a useful quantity of energy from ambient electromagnetic waves - an old band I VHF antenna connected to a capacitor via rectifying diodes will give you enough charge to light an LED after a while, and you could probably power a small CMOS circuit from it.
No, not enough energy to be all that useful unless you are extremely close to a high power transmitter. An exceptionally strong signal into a full-size aerial would give you 100mV at the aerial socket, which assuming a 75 ohm load impedance would amount to 100uW of power.
I remember a school demonstration using a klystron that could light a very small incandescent bulb connected to a tuned dipole, but that of course does not need rectification. Silicon diodes need several hundred millivolts to overcome the junction potential, germanium diodes just behave like capacitors.
I did once manage to produce a rectified DC large enough to deflect an AVO to 5V - using a 5kW cavity magnetron a few metres away, and a microwave diode. It was pointed at the outside corner of a building on the 1st floor, but with hindsight I wouldn't recommend this experiment.
Based on this and a few other RF experiments over the years I have come to a conclusion about the feasibility of this product, and concluded that it simply isn't expensive enough. Like directional OFHC speaker cables and multi-screened low capacitance coax that improves stereo separation on digital signals, if it doesn't cost over $1000 it can't possibly work.
We used to light a small neon bulb by putting it close to the output stage on an HF transmitter. If the colour was purple it was supposed to indicate parasitic oscillations. In which case you fitted a parasitic stopper to the anode circuit - unless there was one already fitted in which case you removed it.
I'm calling bollocks here, however I do maintain an open mind and would like to see independent testing regards to signal degradation in combination with the amount of power harvested. 30% is a wild claim and without that testing this remains in the same category as magic balls, cable lifters and $2000 interconnects in the audiofool world - bullshit and snake oil.
Given that they are sending the power back to the phone via wireless charging, I would seriously doubt that it can get more than 30% of _harvested_ power back into the phone once all of those losses are dealt with.
I would doubt that the phone is using as much as 30% of its power for its radios - the display is usually a bigger drain than the processor, and that is bad enough.
And, of course, I doubt that anything of that sort of size can harvest more than 30% of the RF in the air.
So, what is 30% of 30% of 30% ?
Oh, and what is the efficiency of the battery?
Assuming the phone antenna is pretty much omnidirectional most of the signal is going nowhere useful, so you can "harvest" around half of that with an inductor on one side, and subsequently you'll have to point the other side towards the mast. The only problem is that you'd want to put the inductor on the side that's against the user's head (because the signal in that direction is attenuated anyway) which won't work too well with the screen. But if you're willing to put up with the hassle of a directional phone you might as well engineer one with a directional antenna, that wastes a lot less power transmitting in the first place.
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"You can build a reasonably effective corner reflector for mobile phone out of a couple of cornflakes boxes and some tinfoil. If you make it to a reasonable standard, you can gain 1-2 dB of signal on 900 Mhz. But obviously it's directional."
I was torn between clicking the 'report abuse' link and up-voting. :P
If you had a material that could be controllably transparent to radio frequencies (similar to a liquid crystal watch display) and a way to determine the direction of the mast in use, this might actually work. Make the part of the case in the direction of the mast radio transparent, changing as the user moves. The blocked signal could be absorbed to reclaim some energy, or reflected to boost signal strength.
And that reminded me that back in the Good Old Days of the web (circa 1998), I had read and bookmarked a site which contained, among other things, a nice collection of thought experiments on various sorts of perpetual motion machines, with explanations of why they wouldn't work.
Hmm... I think it might be this one. Good stuff. Comments in the source say it was created in 1996. Ah, those were the days, even if we were already in Eternal September.
Now if you'll excuse me, I have to refuel my lawn-kid-chasing robot.
Another commenter wrote here that radio signals don't account for 30% of the total energy output, but I know what does - the screen. Now if you could have a really efficient solar cell blocking the screen out, you'd be able to recoup even more energy.
That's tongue-in-cheek of course, but it's saying much the same thing as recouping "lost" radio energy i.e. it's complete bollocks
But wouldn't that require expenditure of energy to locate the user's eyes AND to redirect the screen output in the appropriate direction? Plus there's matters of Strabismus (the eyes aren't coordinated and look in different directions) or the presence of more than one pair of eyes.
"But wouldn't that require expenditure of energy to locate the user's eyes AND to redirect the screen output in the appropriate direction?"
Next up from Apple; DLP arrays with each mirror carrying a directional OLED pixel, using Samsung's existing eye detection system which Apple's Comrade Popov invented first*.
I need to get one of my American relatives to apply for a patent, quick.
*As I recall in the days of the Soviet Union every American invention had been invented in the USSR first by a peasant named Popov. It made you wonder why the Soviet Academy of Sciences needed all those members.
Er - there is no conservation of stupidity. Like entropy it increases all the time. This should be obvious because stupidity is the outward sign of lack of mental organisation. If you place a stupid person in a room with an intelligent person and start an argument, the intelligent person becomes more stupid and so does the stupid person. This is how stupidity differs from heat.
Still pretending you can control human nature based on laws from an early Bronze Age book. If you date the start of economics roughly from Sumerian temple records, the human race was a small and threatened species right up till then - whereupon things started to take off. Economic planning pays dividends, as Joseph explains to Pharaoh before getting the next to top job. And the social scientists and psychologists have been in the vanguard of the demolition of sky fairies. Physics may remind us that the first chapter of Genesis was produced by very definite non-scientists, but it's anthropology that explains how the worship of gods evolved as a mechanism of social control.
Still pretending you can control human nature based on laws from an early Bronze Age book.
I fear anti-intellectual bitching about the humanities and social sciences is a staple of Reg discourse. You'll never get that boulder to the top of this hill.
"Stupidity increases all the time, entropy on the other hand is less certain!"
True, the entropy of an isolated system eventually reaches a maximum - though for the universe as a whole expansion means entropy always increases. But stupidity also reaches a maximum in an isolated system - when the ability to reproduce is compromised.
Just think... scale it up and power houses, offices, and factories! No more of those nasty power plants to foul the water, the air, or (in some cases) not generate a nuclear disaster!!!! Why it could even power such cars as the Tesla without ever having to stop at a charging station. Wow...!!!!
It's just like that new electric car they're working on. Going to blow Tesla away. While it has electric motors hooked to two of the wheels, it's got electric generators hooked to the other two, so it recharges itself while you drive!
I'm sure Lord Bong is involved in both these projects somewhere.
All they need to do now is add a SKERS system (Steering Kinetic Energy Recovery System - my invention, already patented in Albania), and a PKERS (Pedal... you get the idea), combined with a standard KERS system, and I bet you I could put more energy into the motor than is being used.
Now I've solved the world energy crisis (because there is one), I've some free time. Anti-Electro-gravity generator powered by Dark Energy, anyone?
Old technology. British Rail had regenerative braking back in the late 1960's on the Class 50 diesel-electric locomotives which ran between Crewe and Glasgow. It was felt to be a good idea to save fuel over the Tebay/Shap/Beattock climbs.
One problem - the locos were diesel-electric, not electric so there was no power supply to dump the regenerated power into when braking. The onboard batteries weren't up to the task (they couldn't provide motive power anyway) so the electricity had to be dumped into the coaches as waste heat. Great in the middle of winter, but bloody awful in the middle of summer in an air-conditioned coach with fixed windows.
When the locos later moved to the Western Region the regenerative gear was ripped out: too much of a PITA to justify retention.
I thought it was the Class 76 electric locomotives on the Woodhead line (1950s-60s) which had regenerative braking, as this was a 1.5kVDC overhead line. The Class 50 had rheostatic braking, i.e. motors used as generators in reverse dumped energy into a heat load. This reduces the wear on the wheel brakes, but does not recover any energy.
Regenerative braking for cars does have its problems, as I discovered when all the brakes on my Prius gunged up from sheer lack of use. I thought at the time, having paid for them to be dismantled and cleaned out after a lack of success on my part, that the design could have been improved.
"The laws of physics aren't laws. They're really the limits to physics.
Limits imposed by our collective lack of imagination"
This bit of sociological fluff is why people continue to believe in perpetual motion machines (of which this phone case is an example.)
The laws of physics aren't limits; they are consistent rules that describe how things work. The law of conservation of energy has been demonstrated to apply on micro and macro scales, and every time an exception seems to have been found (e.g. beta emission) the result has simply been to find a new conservation mechanism (neutrinos in this case.) You are confusing the legal sense of laws (stuff written down in a book about what you are allowed to do that becomes very flexible according to the amount of money you pay your lawyers) with the scientific sense (stuff written down in books based on experiments which, every time and in every place, show a consistent pattern of how things work, and no matter how much you pay a physicist you won't get a personal exception.)
Please, people, let's focus on the positives here...
- No more blaming weak signals on "holding it wrong".
- Your iPhone will finally last an entire day.
- Your iCoolness factor goes up another notch.
- None of that stray wasted energy will contribute to climate change, so Al Gore approves.
- Your energy savings can offset some of Al Gore's jet's emissions.
Huh? Wait... I think I understa... Nope. Still don't.
I think he may be complaining about the claim in the article that the "30% recovery" series diverges (or "asymptotically" approaches infinity), when in fact it's convergent - and indeed only about 1.35, if my calculations are right (they may well not be). Whatever. It's hardly an important point.
This sounds like a great product, but I have it beaten. I have discovered that the iPhone (and, in fact, lots of other phones) can not only accept a charge but CAN ALSO OUTPUT POWER from the charging port (USB in the real-world, some fancy fandango thing if it's in the Apple garden).
My new product (kickstarter link to be added) takes this wasted power and uses it to charge a battery. Much more efficient than RF harvesting!
To the bar; we're rich!
There seems to be a lot of skepticism about this idea, and perhaps it wouldn't work, but I have often wondered if a small wind turbine attached to the bottom of the case could recharge the phones during conversations, especially those with lots of 'P's an 'F's in them.
It could also be reversed to give a cooling breeze, useful when having a heated discussion with a call centre.
Q: If Achilles covers half the distance to his destination every day, when does he arrive?
(Of course, at some point the distance is so small as to be negligible, and impossible in the physical world not to negotiate...)
Even giving the 'inventor' the benefit of the doubt, eventually the charge will be so small, it won't power your phone for the smallest fraction of a picosecond.
"Q: If Achilles covers half the distance to his destination every day, when does he arrive?"
Question needs to be qualified. If "half the distance" is measured as of the start of his journey (which would make sense since most people travel relatively uniform distances), then the answer is obviously "two days". Your answer assumes "half the distance" is measured as of the start of each day.
Zeno's Dichotomy Paradox is only a paradox if you don't understand the concept of a convergent infinite series.
Of course, once you do, it serves as a handy informal argument that the limit of Ʃ(i/(xi)), for any real x in (0,1), is 1. That is, what works for "going half the remaining distance on each iteration" obviously must also work for "going one-third the remaining distance", etc. There's nothing special about "half the remaining distance".
(The paradox as originally formulated divides the unit segment in the other order, with the infinitesimal at zero. Whatevs; it's the same thing, addition being commutative.)
Well, if a certain amount of the signal was crawling back over or through the casing material and becoming a waste energy, why not reclaim it. It's innovation. It's something that most corporate paper pushers in their own internal "Four F" psychology/mentality will never grok. That makes it an imperative for those who operate in a mentally better place to push the envelope to prevent technology stagnation and atrophy.
They will incorporate PoE (Power-over-Ethernet) into the Wi-Fi transreceiver on the device, enabling you to recharge the battery directly from the Wi-Fi signal whilst connected to a PoE equipped access point.
So obvious it's staggering no-one has thought of this before !
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