back to article What a good eye-dea: Battery-less, grain-of-sand-sized 2.4GHz transmitter to help save your eyesight

Scientists have developed a tiny, implantable, self-powered, wireless transmitter chip for monitoring and treating glaucoma patients and other biomedical applications. The 2.4GHz ultra-low power transmitter is about the size of a grain of sand, said Pedro Irazoqui, the Reilly Professor of Biomedical Engineering and professor …

  1. Anonymous Coward

    People don't like batteries

    Rather than relying on a battery, which isn't something people want in their bodies, the transmitter harvests power by converting radio frequency waves into direct current, using cavity-resonator based magnetic resonance coupling.

    Public ignorance seems a very feeble justification. What are you going to do when the idiots learn that the makers of the silicon chip deliberately doped it with lethal poisons like phosphorus or arsenic, or that it radiates microwaves like 5G base stations do?

    1. Gordon 10 Silver badge

      Re: People don't like batteries

      I realise you are trolling, but batteries decompose and go flat. Something that doesnt need batteries is therefore good for all sorts of reasons.

      1. Version 1.0 Silver badge

        Re: People don't like batteries

        Good in the medical world, good for science too - think how easy it will be to track bees and butterflies etc now, essentially they will all be carrying Bluetooth phones (LOL).

        But there are some other uses of the technology too - spies and professional hackers are going to find this useful...

        1. Anonymous Coward

          Re: People don't like batteries

          Good in the medical world, good for science too - think how easy it will be to track bees and butterflies etc now, essentially they will all be carrying Bluetooth phones (LOL).

          Not sure it quite works like that. The journal paper describes the prototype device's 2.4 mm diameter transmitting antenna and the external receiving antenna as being separated by 20 cm of air and 5 mm of rat skin, so we are not talking long range. The way that the device was powered was also quite interesting:

          We developed a resonant cavity based wireless power transfer (WPT) method to deliver power to the device in a freely moving small rodent, where the cavity resonator acts like a cage for the rodent.

          Fortunately the authors proposed that "For human use, we can adopt a conceptually similar but cavity-less, magnetic resonance coupled WPT method", so the patient wouldn't have to put their head or face in a small metal box.

      2. Anonymous Coward

        Re: People don't like batteries

        I realise you are trolling, but batteries decompose and go flat. Something that doesnt need batteries is therefore good for all sorts of reason

        The El Reg article doesn't use these justifications, instead it relies on the emotional - a battery "isn't something people want in their bodies,", "Basically we don't want batteries," and "Nobody likes to have big batteries to wear." It leaves the reader to invent reasons for themselves, which you have done.

        Unless the reader has expertise in implanted medical electronics, they will not know whether the reasons they invent are valid or not. They are just told "batteries are bad". There are, in fact, hundreds of thousands of people in the UK living happily with batteries permanently implanted inside their bodies, and whilst I only know a few of them none have complained to me about having "big batteries to wear."

        1. Neil Barnes Silver badge

          Re: People don't like batteries

          More to the point, how long before the twitterati 'discover' it causes covid-19?

    2. Steve K Silver badge

      Re: People don't like batteries

      I think that the sentiment is that batteries should be avoided due to the possibility of leakage or the fact that when exhausted, the device would have to be extracted/replaced.

      I don't think that the implication here is that the reluctance is due to 5G fruitloopery.

      1. hoola Silver badge

        Re: People don't like batteries

        The point that is being missed is that it the device & sensor is so small that it can be inserted into the eye giving real time pressure monitoring. The receiver is now external to the body and can have normal batteries in, just like any other device.

        Hats of to the team that have come up with this. If this can be developed to be a routine tool in the treatment of Glaucoma then fantastic. Glaucoma is a horrible condition that destroys eyesight and needs constant monitoring. The problem is that if eye pressure rises quickly, by the time it is caught, then eyesight is already damaged beyond repair. Even if the receiver just alerts the wearer then it is progress but to provides a log that can be accessed by the GP, A & E or the Eye clinic alert to the healthcare professionals then even better.

  2. Anonymous Coward
    Anonymous Coward

    Eye Eye

    Grain of sand maybe, implanted in the eye maybe, but it was definitely a good idea to have a hole in the middle of the great big antenna so you can see through it.

    Along the lines of: it just takes just 5 lines of code to do x. (Coupled with 5 million lines of support libraries)

    1. Anonymous Coward
      Anonymous Coward

      Re: Eye Eye

      it's a loop antenna. the hole comes standard

  3. RockBurner

    I'm still waiting for my Neuromancer* style 'augmented reality' contact lenses....

    * IIRC, it's been a while since I read any Gibson.

    1. I ain't Spartacus Gold badge

      Just be grateful the internet doesn't require the Headcrash style VR thing that you have to shove up your arse...

      1. John Jennings Silver badge

        It doesnt?

        I have seen lots in the internet suggesting otherwise....

        1. RockBurner

          It's just not 'required'


          1. I ain't Spartacus Gold badge

            Is it a price worth paying to be able to taste your virtual food in your vitural reality? Or to be be able to kill people really quickly in networked Doom?

            Personally, if I want flavour while online, I'd rather order a pizza. Especially if it's delivered by a guy with two swords from the Cosa Nostra Pizza Company...

        2. Anonymous Coward
          Anonymous Coward

          Might want to tune your search criteria then :)

    2. vir

      I believe it was surgically-implanted lenses over the entire eye socket and the extent of "augmented reality" was a clock in the FOV. But when 3MB RAM is a lot, you make do with what you have.

  4. Pascal Monett Silver badge

    Could someone translate that into English ?

    "For example, it incorporates a voltage-controlled oscillator (VCO) with NMOS and PMOS cross-coupled transistors that support 2x lower startup current and 10.5db lower phase noise at 1MHz offset than an implementation that only uses standard NMOS or PMOS components. "

    All that sounds very impressive and very technical and I have no doubt that it is important, but I can't for the life of me understand what the hell is going on and why it is important.

    Help ?

    1. Siberian Hamster

      Re: Could someone translate that into English ?

      Without seeing the actual circuit to understand if they've come up with a subtle improvement to existing designs, this is likely just the current gen of power circuit that adjusts operating frequency to optimise power efficiency. Effectively the same as in these power bank type devices that take a 3.7-4.2v Li ion cell and output a stable 5v. Older designs use a fixed frequency with varying duty cycle to provide the 5v where the efficiency decreases as the battery voltage drops. Newer designs also vary the frequency as the battery voltage drops which provides better efficiency.

    2. This post has been deleted by its author

  5. anthonyhegedus

    Conspiracy theorists will pick up on this and use it as ammunition for their 'chips injected with the vaccines' trope.

    "see? it's possible to inject tracker chips now!"

    1. Alumoi Silver badge

      Wrong quote, buddy.

      "See, I've told you they were injecting tracking chips. Now they've recognize it."

    2. Chairman of the Bored


      At some point I would hope that natural selection will start to thin that herd. Hopefully the bug that does them in isn't as transmissible as COVID.

      In the meantime, I get to send a kid back to school knowing two of the offspring in his class were sites by anti-vax nuts. Nothing like knowing your kid will be sitting next to Marco Polio.

  6. Anonymous Coward
    Anonymous Coward

    transmitter is about the size of a grain of sand

    The last time I read an article about "grain of sand" sized tech was from a debunked conspiracy story put out by BloomBerg.

    (Or was it the size of a grain of rice?)


    1. Sleep deprived

      Re: transmitter is about the size of a grain of sand

      I have firsthand experience that a grain of sand in the eye is most annoying. But perhaps less than glaucoma.

  7. Strangelove

    Translating. The voltage controlled oscillator (VCO) has a cleaner spectrum (lower phase noise) than previously published efforts (an osc nominally produces a single frequency, but has an intrinsic width to the 'skirts' on either side of the spectrum ). The Authors of the paper made good use of the complementary nature of the 180nm CMOS foundry process to achieve this (perhaps some cunning symmetry allows a degree of noise cancellation ? That is just a guess) . Similar cunning has got the power consumption down (or DC to RF conversion efficiency up ) Even so -33dBm is only 500 nano-watts of transmitter power, and that rather weedy signal plus the small antenna conspire to explain the short range between implant and reader. Which in a clinic full of eye patients may actually be an advantage, rather than a drawback.

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