At Last, (Almost) A Cellphone With No Batteries!

If you are tired of constantly having to worry about the state of the battery in your mobile phone, then maybe help is at hand courtesy of the University of Washington. They are reporting the first-ever battery free cell phone, able to make calls by scavenging ambient power. An impressive achievement, and one about which we’d all like to know more.

On closer examination though, the story is revealed as not quite what it claims to be. It’s still a very impressive achievement, but instead of a cell phone with which you can make calls through the public cell network, it’s more of a remote handset for a custom base station through which it can place Skype calls. Sadly the paper itself is hidden behind a journal publisher’s paywall, so we’re left to poke underneath the research group’s slightly baffling decision to use the word “Cellphone” for something that plainly isn’t, and the university PR department’s dumbing-down for the masses. Aren’t peer reviewers supposed to catch misleading descriptions as well as dodgy science?

In radio terms, it’s an analog AM two-way radio that uses a backscatter transmission technique of applying the modulation as switching to an absorbing antenna tuned to the RF source whose ambient energy is being utilized. This modulates the ambient field within the range of the device, and resulting modulated field can be received and demodulated like any other radio signal. It’s a simplex device, in that you can’t listen and talk at the same time. Other ambient power used by the circuitry is harvested by rectifying received RF and through capturing ambient light on a set of photodiodes. There is a short video explaining the system, which we’ve placed below the break.

It is unfortunate that the detail of this story has been obscured, and that the paper itself remains behind a paywall. The issue of open-access academic journal publishing is probably beyond the scope of this Hackaday article (though if you know who Aaron Swartz was and why he is no longer with us then it should be of interest to you), but it’s safe to say this would be a more positive write-up from the University of Washington’s perspective had they provided more real information and less dumbing-down. If you are interested in backscatter transmission though it’s a subject we’ve covered before, take a look at this FM broadcast transmitter using it.

Via Hacker News.

52 thoughts on “At Last, (Almost) A Cellphone With No Batteries!

        1. Scientific papers *absolutely* don’t use metric units exclusively. They use units that are common in whatever field they’re writing about. Those units are then typically *defined* based on metric units.

          But imperial units are defined based on metric units anyway, so seeing imperial units shouldn’t be any more jarring than seeing light-years or parsecs as units of distance.

        2. @Steven Gann

          We use ‘stone’ (14lb) primarily for body weight, all other uses have long since disppeared, and selling any product with lb/oz is considered illegal in UK (I believe). Bushels may only be a farm/crop thing, and a furlong is only in common use within the horse racing area….but they still also refer to equine sales by the ‘guinea’ and not pound sterling.

  1. The only reason Aaron Swartz killed himself was because he was mentally ill. A sane person in his position would have just run off to some Latin American country and would be have a great time now, with a pile of bitcoin in his wallet too.

    I can link directly to multiple download options for the article, but would you delete my post if I did?

    1. Can I at least point out that if it isn’t on right now it will be soon enough and that realistically those in academic environments, or poorer countries don’t have real barriers to getting articles? It really just disadvantage two groupst, the ignorant, and those businesses who can afford to pay subscriptions anyway, because the journal access work-around are tolerated if you are no blatantly profiting from using them. Mind you Obama almost made that a lot harder, but then poof he was gone and his treaty plans fell in a heap. Do you remember him, Lady Blah Blah’s hero?

      1. Nope, and your Swartz idolisation is pathetic. Killing yourself solves nothing as it erases all hope, you throw away further control of everything in a an ironic act of trying to show you have control over just one thing your own life. It is not the act of a sane person at all.

        1. Agreed, killing oneself is an act of desperation. Illogical. Now, if one were a Klingon, it would be an honorable death if one were to kill oneself while defeating as many of the enemy as possible (whomever the ‘enemy’ might be). It would be an act of glory, assuring the warriors place in Stov’l Kohr.

          I’m reminded of Gowron speaking with Worf – “they will write songs about our deeds”… “glory awaits you on Cardassia”…..

          Somewhat like the “divine wind” of Japanese aviators during WW-II (ie. “kamikaze”s)

        2. Suicide is a grave subject (yea, puns!) and deserves to be treated gravely, or at least with respect for the dead. It helps no-one to be dismissive and derogatory. I think you are just scared by the thought..

          Concerning the earlier post about units, I flicked through the paper looking for the inappropriate units and I must say I didn’t notice that the distances were in in feet and inches and had to re-read to find them. Fair enough, I grew up with feet and Inches, but it is a surprisingly small part of the world population that knows what a distance of ten feet looks like let alone 31.

          It’s a question of who your intended audience is USA or World.

          1. No, suicide is a foolish and wasteful idea, unless you are already half dead and you have a provable lack of reason to believe you can make any further contribution to society. People who quit for selfish reasons deserve nothing but contempt and people should know that if you make such impulsive and destructive choices that you will be remembered as a fool, then perhaps it will make them think twice, give them sufficient pause to allow them to get over that moment of insanity and thereby survive. Your attitude JS may well contribute to more, not less, needless deaths.

            As for the childish arguments over metrology systems, it is all just arbitrary symbols anyway, the absolute values are the physical phenomena those all those systems are defined by.

            How often have you referred to the time of year as Winter etc. when it is never Winter for every human? You are a hair spiting, anally retentive, hypocritical kind of person aren’t you?

    2. People already have linked, and no, we haven’t deleted them.

      Open access is something on which I personally have Views, having worked for a large academic publisher in the past.

      I feel that commenters should maintain a sensitivity when it comes to mental illness, and suicide victims.

          1. Because if you are not in need of mental health treatment you are resilient and realistic, therefore unaffected by adversity and able to hack your way around life’s difficulties therefore the difficulties are irrelevant.

        1. Nobody has suggested that Schwartz’s suicide be emulated. You are pulling that entirely out of your ass and it’s making you grumpy. Try shutting up and going away and see if that cures your butthurt.

          1. Or perhaps you should stop projecting your butt hurt onto me because you are deluding yourself if your really thing I care that much about anything, I simply made a logical and factual point, and idiots like you started over reacting.

    3. Who wouldn’t be incredibly depressed at the prospect of a felony conviction and up to 35 years in prison?
      You don’t have to agree with his actions to disagree with the actions of the DA and courts.

      1. I already pointed out that he was not facing that at all, at worse he was facing a temporary exile. He could have continued to contribute much good to humanity, if he was sane and saw the many obvious ways out that were creative rather than destructive.

  2. “If you are tired of constantly having to worry about the state of the battery in your mobile phone, then maybe help is at hand courtesy of the University of Washington. ”

    I’ve recently switched back to my old feature phone and that’s no longer a problem Only my old Nokia was better.

    1. That’s just because your old feature phone doesn’t have the advanced features of an Android or Apple phone. If you use those fancy features sparingly, it’s surprising how long the battery last. My Galaxy S3 running Android 7.1 last for days on end on battery. All I use it for is making calls, texting, checking emails and reading websites that aren’t picture heavy. If I plan to play a game then I do keep a charger with me but I stopped doing that when I got bored of yet another skin on the same game. Web browsing is a bit challenging, have to use a pretty intense adblocker or I’ll see my battery life go to crap in no time. I’ll never understand that mentally that places advertisements above battery life, what good are advertisements you can’t see because they’ve drained your battery.

  3. Correct me if I am wrong, but I remember a battery free am transceiver kit that was in POP Science magazine catalog in the 1990’s, it used a 8 ft antenna and a grounding wire to work and could transmit around 15 ft without a battery

    1. You hit the nail on the head. I’m on a gluten free diet and everyone goes “wow so healthy” and then I explain that instead of whole grains I eat processed corn products. Anyone without a gluten intolerance who eats gluten free has been duped by marketing into eating expensive, poorly flavored, unhealthy food.

        1. GF bread is usually a mixture of tapioca, rice, corn, etc. It doesn’t fill you up like whole grain wheat bread, molds quickly unless frozen, and only comes in small slices. It’s usually oversugared as well (I don’t know why).

      1. So the poor people that almost exclusive eat rice backed with a few extra ingredients are eating expensive food because they have been duped by marketing?

        Stop being an idiot and think before you write. Even if you’d be referring to the region where _you_ live (whatever that is) your statement wouldn’t be true. Rice is cheap even in the “west” and anyone that don’t like pasta or bread lives gluten free without being duped by anyone.

        1. Nah, the expensive part is the “gluten-free” label the marketing people slap on the box.

          Gluten free advertised products are to Apple as rice and other grains are to PC.

        2. It’s true that eating things that aren’t rice is a “first world problem.” However I personally like to eat cereal, make sandwiches, travel, eat pasta, eat granola bars, etc. It would be quite difficult for me in the USA to switch to eating rice for breakfast, lunch and dinner. To have the luxury of making a sandwich I have to buy expensive, unfilling bread made from tapioca or corn or white rice, whereas I used to eat whole grain bread that was actually filling.

        3. I don’t see what this has to do with the diet of poor people in Asia/India/Africa? I’m speaking only about my own attempts to get food in the USA. Also, just because there are poor people who eat only rice doesn’t mean that their diet meets their nutritional needs– in fact quite the opposite.

      2. Life is more complicated. As a child I recall no one who was ‘intolerant’ of a food and only recall one child who was asthmatic. Now, you cannot fart without hitting someone allergic to beans, eggs, bees, bee farts, wheat, beet, or processed meat, or something else.

        1. I don’t know if there’s an increasiing trend or not. I just know that when I turned 18 my stomach was upset 24/7 and I was like 115 lbs and dropping. Figuring out it’s a specitic food intolerance was extremely difficult, you basically just cut random things from your diet and wait months. I suspect that historically people suffered from intolerances but didn’t discover the causes.

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