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Diodes Could Drive Swimming Micro-Robots

Posted by CowboyNeal on from the robot-parade dept.

finisterre writes "Diodes can be made to 'swim' through salt water by hitting them with an alternating electric field. The applied field induces a current that sets up a field between the diode's electrical contacts and creates a propulsive force. The abstract of the paper in Nature Materials is freely available. New Scientist has videos of the swimming diodes in action."

51 comments

  1. Uhhh by malkir · · Score: 3, Funny

    I for one welcome our robotic sperm overlords.

    1. Re:Uhhh by dintech · · Score: 2, Funny

      No robosperm for me thank you. Because hitting them with an alternating electric field sounds like quite a painful thing to do to yourself. :P

      Then again, if implemented properly it does open a whole new realm of two-handed typing...

    2. Re:Uhhh by BiggerIsBetter · · Score: 1

      Eh? Malkir doesn't sound like a Japanese name.

      --
      Forget thrust, drag, lift and weight. Airplanes fly because of money.
    3. Re:Uhhh by Anonymous Coward · · Score: 1, Funny

      I for one think your both a pair of assholes regurgitating worn out jokes!

  2. Reading this before properly waking up... by ricky-road-flats · · Score: 4, Funny
    ... I read dildoes instead of diodes, and I can't even think of a joke for it.

    That's what I get for hitting Slashdot before the first morning coffee. Once I have that buzz I might be able to think of a punchline.

    1. Re:Reading this before properly waking up... by nicklott · · Score: 1

      Sorry, you can't blame the coffee anymore...

    2. Re:Reading this before properly waking up... by MightyYar · · Score: 3, Interesting

      You need to re-read that article. It simply states that coffee drinkers are no more alert than non-coffee drinkers; it does not say that regular coffee drinkers are just as alert before and after their first cup of coffee. In fact, it explains why regular coffee drinkers need the morning cup to come back up to a baseline of normal alertness.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
  3. leave your taser at home by User+956 · · Score: 3, Funny

    Diodes can be made to 'swim' through salt water by hitting them with an alternating electric field.

    And yet for some reason this same method doesn't work so well on people.

    --
    The theory of relativity doesn't work right in Arkansas.
    1. Re:leave your taser at home by Shemmie · · Score: 3, Funny

      That's not true. I connected my local swimming pool to the mains voltage to test the theory - after that, they all floated.

    2. Re:leave your taser at home by edwardpickman · · Score: 1
      And yet for some reason this same method doesn't work so well on people.

      Are you sure? Have you tried it out? This is science man and it requires exhaustive testing. Take your taser to a pool and let us know the results.

    3. Re:leave your taser at home by agent+dero · · Score: 1

      You just aren't applying enough current...

      No but seriously, you can make muscles twitch a'plenty with the application of electricity, we did it on dead frog legs back in the school once. Try it on your favorite dead-frog/spouse/roommate of choice

      --
      Error 407 - No creative sig found
  4. Voltage? by AmIAnAi · · Score: 2, Interesting

    Anyone know what voltage was used here. Personally, I don't fancy being hooked up to the AC to drive nano-scale surgical robots round my body.

    --
    Any sufficiently advanced bug is indistinguishable from a feature.
    1. Re:Voltage? by Bromskloss · · Score: 2, Informative

      Anyone know what voltage was used here.

      They used an electric field of 3000 V/m to 15000 V/m. Using the distances they said they had between the electrodes, it seems that for these particular experiments, the voltage was in the range of 75 V to 1050 V.

      --
      Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
    2. Re:Voltage? by Anonymous Coward · · Score: 0

      That's... that's a pretty large range.

      You sure you didn't mean to write 150 V?

    3. Re:Voltage? by Bromskloss · · Score: 2, Informative

      That's... that's a pretty large range. You sure you didn't mean to write 150 V?

      I actually meant what I wrote. I got 75 V from multiplying the weakest electric field with the shortest distance I found they had between electrodes and, 1050 V from multiplying the strongest electric field with the longest distance. That is not to say that they actually used the combinations necessary to produce these extreme values, but just that the voltages have to be somewhere in between.

      --
      Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
    4. Re:Voltage? by tenco · · Score: 1

      You don't need to be hooked up to AC to have an AC electric field applied to you. Just stand between the plates of a big enough capacitor.

  5. Toy + Publicity Stunt by Bender_ · · Score: 2, Interesting


    That is all there is. The propulsion principle has been known for at least a hundred years. The only 'new' thing is to use a diode to generate a DC field from externally applied AC. But actually that does not really solve any practical problem.

    1. Re:Toy + Publicity Stunt by Tdawgless · · Score: 0

      You'd need two diodes to make pulsed(half-wave) DC and four diodes to make DC(full wave). I don't think this is what they're doing. They're making *propulsion* with a diode by feeding it AC, not trying to make DC.

    2. Re:Toy + Publicity Stunt by Anonymous Coward · · Score: 0

      There are also issues with too high a voltage - electrolysis generating gases bubbles (oxygen, hudrogen and chlorine) inside the blood stream.

    3. Re:Toy + Publicity Stunt by Bender_ · · Score: 1

      Bull.. - please review your electronics 101 notes.

    4. Re:Toy + Publicity Stunt by hey! · · Score: 2, Insightful

      The propulsion principle has been known for at least a hundred years. The only 'new' thing is to use a diode to generate a DC field from externally applied AC.


      Sure, and the internal combustion engine consists of simple machines like levers and wheels that have been known for millenia, it's just arranging them so they can convert intermittent explosions into smooth rotational movement that's new.

      Finding surprising new uses for old ideas counts as a new idea.
      --
      Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
    5. Re:Toy + Publicity Stunt by Goaway · · Score: 1

      The only 'new' thing is to use a diode to generate a DC field from externally applied AC.

      From an externally applied AC field. If you don't think that idea is new, care to show some earlier examples of it?

    6. Re:Toy + Publicity Stunt by Bender_ · · Score: 1


      Please google Onsager, Faraday, Nernst and all the other pioneers of electrochemistry.

    7. Re:Toy + Publicity Stunt by Goaway · · Score: 1

      http://www.google.com/search?q=faraday+diode+propu lsion
      http://www.google.com/search?q=onsager+diode+propu lsion
      http://www.google.com/search?q=nernst+diode+propul sion

      I can't seem to find what you are referring to. Care to point me in the right direction?

    8. Re:Toy + Publicity Stunt by Bender_ · · Score: 1


      Cute...

    9. Re:Toy + Publicity Stunt by Goaway · · Score: 1

      Quite. See the point being made yet?

  6. and what is the application? by rucs_hack · · Score: 1

    Ok very nice, but is there a use?

    I see something I am quite familiar with in scientific papers, lots of complex ways to say simple things to disguise the fact that they haven't the feintest idea what this can really be used for.

    Take the nuggets:
    "microfluidic channels"
    "global external field"
    "decoupling of the velocity of the particles"

    All appearing in the abstract, with a definite avoidance of plain English.

    I mean, wtf is that all about? I see not a single practical application mentioned with a decent justification for that application being superior or equivalent to some other method. They have speculated greatly, but tested nothing of consequence. That's not good science
    I'm sorry to say I see this a lot in papers, the less certain the authors are that their work is actually useful, the greater the use of complex terms that decompose to trivially simple statements.

    What we have here is a case of premature publication.

    It's very interesting, but come on guys, apply it to something of use.

    1. Re:and what is the application? by ArsenneLupin · · Score: 2, Interesting

      I see not a single practical application mentioned with adecent justification for that application being superior or equivalent to some other method. Actually, they did mention one application: medical microrobots. And they mentioned why their method might be superior to other methods (such as a micromotor driving a ship-screw):

      But extrapolations of the team's measurements indicate the propulsive force will work just as well at smaller scales. "The propulsive force scales in exactly the same way as the drag. That's quite significant," says McKinley.
      ==> drag would be a problem for other methods, but not for this one.
    2. Re:and what is the application? by rucs_hack · · Score: 1

      I got that, but there was, so far as I could see, no evidence of an attempt at practical aplication, just speculation.

      It may well be fabulous, but it seems to me they have this interesting thing, but no evidence of it actually working on application to a problem

    3. Re:and what is the application? by WilliamCotton · · Score: 1

      There is a reason that the words "science" and "technology" refer to two different concepts. One pertains to a method used to discover properties of the world around us and the other refers to using those properties to do interesting things.

      Was Hans Christian Ørsted doing bad science when he discovered the relationship between electricity and magnetism? Should he have waited until he himself discovered the basic laws of electromagnetism? Or is that not enough either? Should he have come up with the electric motor or the telephone before he told anyone?

      Actually, the better analogy would be the story of someone like Gian Domenico Romagnosi, who is believed to have discovered the electromagnetic relationship 20 years prior to Ørsted. Strangely, his publishings were overlooked by the scientific community. He was probably discouraged from further research by people around him saying, "So what? Get back to us when you have a practical use for your silly experiments."

      There is a symbiotic relationship between science and technology. Much great science is based on discovery. Much great technology is based on someone else noticing the benefits of such discoveries.

      --
      I've always prefered a command line interface. GUIs are such a cursory way to interact with a computer.
    4. Re:and what is the application? by PitaBred · · Score: 1

      Too bad your ancestors didn't die out when they said the same thing about the discovery of fire...

      --
      My blog. Good stuff (when I remember to update it). Read it.
    5. Re:and what is the application? by rucs_hack · · Score: 1

      I seriously doubt that someone discovered fire then tried to find a use for it.

      More likely they encountered fire and noted its effects, initially that predators were afraid of it, and it evolved from there.

      Early humans had no free time for abstract thought, a thing was either immediately useful or it wasn't utilised.

      Abstraction, and research (of a kind) did not occur until man had found ways to domesticate animals and obtain more reliable food sources. Once the daily need to hunt all day was gone, things got easier, and we could ponder.

  7. Possible medical uses by gavink42 · · Score: 1

    The first linked article has some discussion of using this technology inside the human body. I can envision the power source being provided by something like an MRI machine... person lays on the table and is moved inside the field that would power the "bots".

    If they can overcome the issues mentioned and make the machines small enough, there are a wide range of uses that I can think of. Treating individual cancerous cells instead of bombarding the entire body with kemo immediately comes to mind!

  8. Stealth by DigitAl56K · · Score: 1

    Cover the outside of a sub with them and get stealth propulsion.

    1. Re:Stealth by Walt+Dismal · · Score: 1

      Navy has it. USA, Russians. You just don't hear about it. Magnetohydrodynamic propulsion and very noiseless. You run current through seawater in a magnetic field and get a propulsive flow. However, with seawater the electrodes tend to get eaten away unless they have platinum surfaces. Platinum is $1200 an ounce but the technology is usable. Now that I've told you, I'll have to shoot you.

    2. Re:Stealth by Anonymous Coward · · Score: 1, Funny

      mmmm....a submarine covered in LEDs.

      Would look pretty cool, but I doubt it would be very stealthy.

      Plus you'd get giant squid attracted by the light trying to mate with the sub.....messy

    3. Re:Stealth by KokorHekkus · · Score: 2, Informative

      Not just US and russian navy but also Mitsubishi. They built the experimental boat Yamato 1 http://en.wikipedia.org/wiki/Yamato_1. Just wanted to give you a heads up before you shoot anyone for no reason you know ;-)

    4. Re:Stealth by Walt+Dismal · · Score: 1

      Um, as a matter of practice, I never shoot anyone for no reason, taking my cue from Kirth Gerson; he's dedicated to the point of obsession but logical enough about these matters. I'd heard of, but neglected to mention, the Japanese, thanks on this.

  9. Swimming with Diodes. by fahrbot-bot · · Score: 2, Funny
    "Diodes can be made to 'swim' through salt water by hitting them with an alternating electric field.

    Now if they can mount freakin' LASERs on them as well...

    --
    It must have been something you assimilated. . . .
    1. Re:Swimming with Diodes. by arktemplar · · Score: 1

      from the article "These rudimentary self-propelling devices can emit light or respond to light and could be controlled by internal logic." I think using laser diodes would emit lasers, and kill two birds with one stone,

      --
      blog plug -> The Darker Side of Light
    2. Re:Swimming with Diodes. by PPH · · Score: 1

      I, for one, welcome our laser armed, diode propelled robotic shark overlords.

      --
      Have gnu, will travel.
  10. Hold on here... no wires? by Anonymous Coward · · Score: 0

    So, we've just discovered electricity in the past few hundred years and discounted the whole "ether" theory of the universe which means electricity must use some sort of direct particle-to-particle transfer (I'm going to create a word for this: "electron" just for convenience sake) but now some scientists are now CLAIMING that you can somehow have electricity jump to somewhere without wires?!? Just for convenience sake, let's call this new technology "wireless".
    Bear with for a second here... if I were to rapidly turn on, turn off, turn on this wireless electricity transfer, "modulate" it if you will... You could actually transmit information to these swimming micro-robots. So not only could you power them, you could actually send them simple directions or other simple commands WIRELESSLY.
    I see BIG possibilities here for this "wireless" technology. These swimming micro-robots, in addition to receiving simple directions, could also SEND stuff back using this same wireless technology. And if that is possible, then (again, bear with me here...I'm getting in VERY deep).... people could carry around these swimming micro-robots and communicate between themselves. I'm not a big fan of the term "micro", I like a biological, back to nature view, so I'm going to go with something biologically small, like a "cell" and since robots are essentially phoney people... they can be referred to as "phoneys"... so this new invention could be called "wireless cell phoneys". I'm going to run off to the patent office right now to file, but I predict that one day, almost everyone will be carrying them.
    Oh, also...I've been in a medically induced coma for the past hundred years... I'll stop by the library on the way out to catch up on the latest news.

  11. Red October's silent propulsion by earthforce_1 · · Score: 1

    Remember the hunt for Red October and it's super silent caterpillar drive with no moving parts?

    --
    My rights don't need management.
  12. Re:And me... by Anonymous Coward · · Score: 0

    Whoever modded the above Offtopic needs to hand in their geek badge. H2G2 references are never Offtopic.

  13. I wonder if this scales in the other direction? by mmell · · Score: 1
    Caterpillar drives for submarines?

    Easily detectable (by their electromagnetic signature), but fast and quiet - no moving parts.

    1. Re:I wonder if this scales in the other direction? by Anonymous Coward · · Score: 0

      Not necessarily. A simple degaussing system could nullify the electromagnetic field outside of the ship so that only a minimal EM signature is present. The US Navy has been using such equipment since at least the 1940's.

  14. Great by Trogre · · Score: 1

    Now they'll just tell me I need to go for a swim.
    I don't think they'll *ever* get around to fixing this terrible pain in all the diodes down my left hand side.

    --
    "Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife