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Wii Technology Science

The Wii's MEMS Inventor on Future Technology 118

Posted by Zonk
from the wii-wii-wii-all-the-way-to-the-bank dept.
eldavojohn writes "IEEE Spectrum is running an article on the inventor of the motion sensor that the Wii uses. The microelectromechanical system (MEMS) gives Wii its core ability to sense motion in the controller. What's really interesting is where Benedetto Vigna wants to take this technology. He has plans to make the sensor smaller and tougher, and hope to place it inside of things like shoes, textiles, and medical devices to aid in data collection. He continues, 'Then I want to make a three-dimensional gyroscope, to measure rotation around three different axes. Today, such products are quite big, a cube 10 centimeters on a side. We want to do this in less than a 30-millimeter cube, to serve as an image stabilizer in cameras and to track a person's position in the intervals when he can't get a GPS signal.'"
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The Wii's MEMS Inventor on Future Technology

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  • Position tracking? (Score:2, Insightful)

    by wamatt (782485) *
    How could it be used to track position? I thought the MEMS inside the WII Controller needed constant calibration with the main unit. If you walking around in the forest what is your fixed frame of reference?
    • by aweinert (969529) on Friday March 02, 2007 @07:37PM (#18213448)
      GPS for gross location, MEM gyroscope for tracking small changes in velocity, position, orientation, etc., and when GPS fails.
    • by pavon (30274) on Friday March 02, 2007 @07:43PM (#18213514)
      It is integrating your velocity to estimate where you are between GPS solutions. Navigation and guidance systems for high velocity (read military) devices do this already out of necessity. However, it would also be useful for low velocity situations where you have a spotty GPS signal. In that situation it doesn't have to be perfect to be usefull, especially if the display indicated the approximate error in the estimation by drawing a circle for your position rather than a dot.
       
      • Before someone catches me on this, MEMs devices like this measure acceleration, not velocity like my previous post implied. Same priciple though, just have to integrate twice. The 6-axis part is important as measuring your rotation in addtion to linear acceleration enables you to keep track of what direction you are pointed.
        • Re:Clarifiation. (Score:5, Informative)

          by smallfries (601545) on Friday March 02, 2007 @09:35PM (#18214284) Homepage
          The principle is the same although the practice is different. Each integration accumulates error, so adding the extra layer degrades the performance.

          These ideas aren't new and have been knocking around for a while. The article sounds a little like hype / ego-wanking, but then again IEEE Spectrum articles normally are. There is a ton of work on "sensor fusion". The basic idea is to take several low-grade position sources and then fuse them together to create a (hopefully) high-accuracy position source. The robotics and wearables communities have been looking at this for many years. One nice approach is combinng the sensor inputs in a Kalman filter which does actually create a higher accuracy signal than any individual source.

          As far as the claims about 3d gyroscopes being the next big thing when they are reduced in size - we saw a demo of a commerically available product about two years ago. It is a 1cm cube that intergrates several accelerometers and gyroscopes to provide a dead-reckoning position source that is accurate to within 5cm. It was very impressive, although the cube cost several thousand pounds. It would be pretty amazing to see Nintendo pick up on something like that.
      • Toyota Priuses (Prii?) and many other cars do dead reckoning in their onboard GPS systems already. (to varying degrees of success might I add)
        • Toyota priuses are constrained to motion in one dimension: forward/backward in the direction the wheels happen to be pointed in. and at the speed the wheels happen to be turning. There is no need for accelerometer for rudimentary dead reckoning in one, but airplanes and even hikers would have a use for it.

          But there is a MEMS accelerometer in a Prius. Without it, the side-impact airbags would be impossible, and the regular airbags would be dangerous.
      • Yeah, its called navigation by dead-reckoning, Navigators used it all the time before GPS, when they could only calculate their exact position every few minutes, hours, or days. They use all the info they do have like speed and direction to estimate where they are in relation to their last known location. This is why, ships in the old days would get lost if they had long periods of bad weather which prevented them from seeing the stars.
  • by Checkmait (1062974) <byron@pharew3.14159are.com minus pi> on Friday March 02, 2007 @07:33PM (#18213404)
    Application of this could be interesting especially in places when a little bit of lag does not hurt anything. I have a hobby of photography and a good digital image stabilizer is would be the best thing since sliced bread.
    • by Bistromat (209985)
      There are plenty of lenses that are image-stabilized with gyros and moving lens elements. Look up the Panasonic Lumix series, or Canon's "IS" lenses.
      • Re: (Score:3, Interesting)

        by TubeSteak (669689)

        There are plenty of lenses that are image-stabilized with gyros and moving lens elements. Look up the Panasonic Lumix series

        http://www2.panasonic.com/webapp/wcs/stores/servle t/MegaOISExplained [panasonic.com]

        Your comment seems to suggest that the removable lens itself has the stabilization.

        My understanding is that the camera does the stabilization with an internal, movable lens & some fancy onboard processing.

        • by Bistromat (209985)
          Incorrect. The lens itself does the stabilizing, with accelerometers and a movable lens element. Linear ultrasonic motors shift the lens in the X and Y axes, effectively shifting the center of field.
    • by SuperBanana (662181) on Friday March 02, 2007 @08:39PM (#18213928)

      Application of this could be interesting especially in places when a little bit of lag does not hurt anything. I have a hobby of photography and a good digital image stabilizer is would be the best thing since sliced bread.

      Please stop spreading the myth that "digital image stabilization" is a valid technology. It's nothing but snake oil by digital camera companies desperate to compete in a flooded market, and an attempt to trick consumers who don't know better (and screw with the results presented by "product selectors".)

      REAL image stabilization uses a servoed prism inside the lens; the image is optically stabilized by sensing movement and adjusting the prism to correct. Current systems from Canon can compensate between 2 and 3 stops; dunno about Nikon's, but it is probably about the same. The systems work gloriously well, though they only compensate for movement of the LENS, not movement of the subject. A slow exposure will still be a slow exposure; if the subject is waving, their hand is going to be blurry. There's no substitute for light, sensor sensitivity (and low noise at high sensitivity), and maximum aperture (how "fast" the lens is. Smaller f-stop numbers are wider, and hence faster.)

      FAKE "image stabilization", which Olympus (among others) are pushing- it only cranks up the sensitivity of the sensor to shorten exposure time. This only results in shorter exposures- and a LOT more noise, especially since most consumer cameras have tiny little sensors (the smaller each sensor pixel, the less light it collects, and the more it needs to be electrically amplified.) You can do this on *any* digital camera with adjustable ISO!

      • Please stop spreading the myth that "digital image stabilization" is a valid technology... REAL image stabilization uses a servoed prism inside the lens

        First of all, you are contradicting yourself.

        I might point out that when I refer to "digital image stabilization," I refer to digital image stabilization using sensors in the camera, not decreasing exposure time or correcting for subject movement. These are entirely different, and plus I have not named any specific companies (unlike you) and judged their products which are advertised to offer "digital image stabilization." Even you are admitting the technology is valid by saying that Canon uses it.

        The

        • Re: (Score:3, Interesting)

          by SuperBanana (662181)

          The Wii motion sensor (if its lag is improved), well-adapted, would produce an excellent motion sensor much more responsive and better than current technology.

          Current technology ALREADY DOES, and it does it precisely enough to allow THREE STOPS OF SLOWER EXPOSURE SPEED. I have a lens in my camera bag made a couple years ago that has MEMS sensors in it.

          Just because you first heard about MEMS in the Wii remote's sesors doesn't mean the military, commercial, and consumer electronics sectors haven't been

        • The difference being whether it is all electronic or partly mechanical/optical.

          I really haven't heard of a circumstance where good "electronic image stabilization" (also known as EIS, non-optical stabilization) surpasses good optical image stabilization (OIS). Another partly mechanical system that hasn't been surpassed by an electronic system is gyroscope, the best mechanical gyros have a lot less drift than an electronic gyro, at least according to an EE/aviation guy that I know. This MEMS system will si
      • by Mike1024 (184871)
        REAL image stabilization uses a servoed prism inside the lens; the image is optically stabilized by sensing movement and adjusting the prism to correct [...] FAKE "image stabilization", which Olympus (among others) are pushing- it only cranks up the sensitivity of the sensor to shorten exposure time.

        Here's how it could work: Instead of taking one exposure for 1/10 seconds, take 50 exposures each 1/500 seconds. Use your MEMS accelerometer to detect how much the camera has moved between each exposure, offset
        • Re: (Score:3, Informative)

          by Speare (84249)
          Erm, except to do it your way, each of the microexposures have to be quantified before they could be shifted and averaged, and when you quantify a high-gain low-photon data set, you INCREASE the amount of noise in the final data. Also, since it would take some time to decide how far to shift each of the microexposures, you're now taking longer to get a total of 1/30sec of actual photon-catching exposure, and fast-moving objects would appear to be stuttering along instead of smoothly blurred.
          • by Mike1024 (184871)
            and when you quantify a high-gain low-photon data set, you INCREASE the amount of noise in the final data

            What particular noise source do you mean?

            Scan-out noise isn't really a problem on modern CCD designs, and quantisation noise wouldn't be a problem because you could just quantise over a scale 1/50th the size.

            Also, since it would take some time to decide how far to shift each of the microexposures, you're now taking longer to get a total of 1/30sec of actual photon-catching exposure

            We can integrate and re
    • by DittoBox (978894)
      Absolutely. Adding Image Stabilization to a lens usually doubles its value, anything that makes it cheaper is all good in my book.

      Image stabilization reduces or removes the effect of camera shake when using longer exposure times. One can get 1 or 2 full f/stops of light out of a lens by using Image Stabilization. If you take a photo at anything under 1/30 of a second with a short (under 90mm focal length) lens you can expect some amount of camera shake while shooting hand held. Image Stabilization will allo
    • Re: (Score:2, Funny)

      Comes in real handy if you are usually drunk when you use your camera. If only they made a camera that would refuse to take pictures that you will regret the next day.
  • by zappepcs (820751) on Friday March 02, 2007 @07:34PM (#18213414) Journal
    I have not played with a Wii yet, but knowing something about robotics I can say that if they manage to get a 3D sensor set working, and cheaply, it will advance a gazillion projects. Knowing how and when to place mechanical effectors and movement of devices is a terribly difficult problem generally. This type of sensor will help do that very effectively.

    This can be used in conjunction with other sensor systems to do things like create a lawnmower robot that doesn't just wonder around till you turn it off. Being able to manage calculation of 3D space is very intensive, but doing so lets us get one step closer to the robot maid and other cartoon dreams of days gone by.

    Its not just for games. Most of the semi-successful DARPA grand challenge vehicles used a similar device for navigation support. The reality of a car that drives you (in Soviet Russia) to work without any intervention from you is getting very close. Inertial navigation (AFAIK) relies on 3D motion tracking to determine the motion in between points of absolute (or relatively absolute) positioning data. So, in between GPS readings, inertial navigation estimates where the robot/car/vehicle is in relation to previous GPS readings. I've seen robots do this already, its just not cheap enough for everyone. A small R/C sized robot can travel 1/2 mile and return to its starting point with high accuracy despite obstacles using inertial navigation. This can be applied to a lot of systems.

    • by HappySqurriel (1010623) on Friday March 02, 2007 @07:52PM (#18213594)
      I'm going to start by saying I know very little about robotics ...

      I could see how something like this could be useful because (much like the inner ear for humans) a device like this could be used to aid in the balance of robots. I could be wrong but it seems like most robots are currently designed to "walk perfectly" a feat which escapes most people; how often have you stubbed your toe or tripped on a stair? If a robot knew that its "body" was no longer in balance it might be able to correct for the "mistake" before it falls and (in essence) no longer be required to "walk perfectly" in order to walk effectively.
      • by jemecki (661581)
        Sorry, but you ARE wrong -- robots don't need [honda.com] to "walk perfectly" right now.
          • "http://www.pinktentacle.com/2006/12/asimo-help-me - ive-fallen-and-i-cant-get-up/"

            I don't know how conclusive that is. It looks like the robot froze or lost power.
            • by maxume (22995)
              It keeps talking. I would call falling backwards down the stairs on a glitch the need to 'walk perfectly', but I admit that there is plenty of room for hair splitting.
              • "It keeps talking."

                I don't know about the show in that video, but when I saw the Asimo at Disneyland, it was pretty clear its voice was pre-recorded and pumped through the speakers. I'd be surprised if the robot itself was doing the talking.

                "I would call falling backwards down the stairs on a glitch the need to 'walk perfectly'..."

                Sure, if you were to throw the context of this conversation right out the window, you'd be right. In the mean time, you're making broad generalizations from a video that tells y
    • by s2jcpete (989386)
      10 centimeters on a side isn't much of an issue for a robot maid, or a lawn mower.
    • if they manage to get a 3D sensor set working, and cheaply, it will advance a gazillion projects.

      Wha? 2-axis MEMS single chip accelerometers have been around for years, and 3-axis units are $5 a pop: http://www.analog.com/en/prod/0,2877,ADXL330,00.ht ml [analog.com]. Dimensions are 4mm by 4mm by 1.5mm, moreless the size of the letter M. Of course the accelerometer does not directly give out a position; you have to filter the output, integrate for velocity and then integrate again for position. Not trivial, but doable.

  • 10cm on a side? The Analog Devices ADXRS150 is a relatively accurate MEMS gyro in 1cm x 1cm. Three of those give you a 3D gyro platform more than good enough for flight stabilization or image-stabilizing a camera. I've done both with them.

    They aren't up on par with inertial-navigation-grade systems using fiber-optic gyros, so their drift tends to make them unusable for long-term navigation. You wouldn't fly a cruise missile or an ICBM on them. But for sensing motion, or for aiding navigation in conjunction
  • are very small. That is why miniature helicopters suddenly became popular. Certainly not 10cm on a side anymore.
  • I have been working on identifying activities (with some success :-) ) of humans using accelerometers placed in clothing, so I believe that the vision of Vigna is something that is quite realizable! I hope to see this technology successful...
    • Some of us would rather not have our own clothing reporting our location and activities elsewhere!
    • I have been working on identifying activities (with some success :-) ) of humans using accelerometers placed in clothing, [...]

      Somehow that sounds a bit... I dunno... Scary? ;-)
  • It's been done (Score:4, Interesting)

    by inviolet (797804) <slashdot AT ideasmatter DOT org> on Friday March 02, 2007 @08:03PM (#18213668) Journal

    He continues, 'Then I want to make a three-dimensional gyroscope, to measure rotation around three different axes. Today, such products are quite big, a cube 10 centimeters on a side. We want to do this in less than a 30-millimeter cube [...]

    Someone should tell him about the solid-state gyros already in use in aircraft instruments. Six years ago at Oshkosh I played with an all-electronic artificial horizon instrument. IIRC, it uses those funky crystals which exhibit piezo-type effects when rotated in space. The entire unit, including LCD, CPU, power supply, backup battery, and of course the three solid-state gyros, was a cylinder about 3"x3"x12".

    Even in its infancy, the device was massively, hilariously more reliable than the steam-powered mechanical gyros that are currently standard fare for General Aviation.

    And that was six years ago.

    All this time, I've been thinking (quite wrongly) that the Wii's controller used these same devices.

    • Hmmm... yes, I think you have a point. The motes developed @ UC-Berkeley have honeywell accelerometers installed on them that are pretty small (abt 1cmx1cm). Although, they are 2-dimensional. But, honeywell has a plethora of these devices on their website, so I think that there is a hullabaloo about something that is already existent. Nevertheless, I would like to see these devices being used in our daily lives!
      • by xenocide2 (231786)
        The motes done by crossbow that I've seen all use STmicro accels. They're 2d but we went and sourced a 3d version rather than try to do the math on a pair of 2d guys.
    • Ya, it's been done by TONS of people. Pretty much any small UAV has exactly what he's talking about. You'd think that a guy that was so involved with the technology would already know what's out there.
    • It's been done for other applications too, by hobbyists, inventors and engineers using the Honeywell/PointResearch miniature DRM and GyroDRM - these belt mountable units supliment GPS positions with dead reckoning when no GPS signal is available (canyons, mountains, cities) for under $3000. [honeywell.com]
    • by sholden (12227)

      Someone should tell him about the solid-state gyros already in use in aircraft instruments. Six years ago at Oshkosh I played with an all-electronic artificial horizon instrument. IIRC, it uses those funky crystals which exhibit piezo-type effects when rotated in space. The entire unit, including LCD, CPU, power supply, backup battery, and of course the three solid-state gyros, was a cylinder about 3"x3"x12".

      So about 75% larger than the product described by: "Today, such products are quite big, a cube 10 ce

    • Integrated with a magneto-inductive device instead of a mini-gyro, the MEMS device becomes a dead-reckoner for orientation and movement. The combined device then gets OEM'd to all sorts of new input devices.
  • already done (Score:4, Informative)

    by jimmydevice (699057) on Friday March 02, 2007 @08:09PM (#18213716)
    The Crista Inertial Measurement Unit is a very small three axis inertial sensor that provides high resolution digital rate and acceleration data via serial interfaces. It uses MEMS gyroscopic rate sensors and accelerometers mounted on orthogonal axes to provide 300 /sec rate and 10G acceleration data. Small (2" x 1.5" x 1", 37g ) http://www.cloudcaptech.com/crista_imu.htm [cloudcaptech.com]
  • Already there (Score:4, Informative)

    by truckaxle (883149) on Friday March 02, 2007 @08:29PM (#18213870) Homepage
    FTA "Then I want to make a three-dimensional gyroscope, to measure rotation around three different axes. Today, such products are quite big, a cube 10 centimeters on a side."

    There are such devices now that are compact and capable, such as...

    http://www.microstrain.com/3dm-gx1_specs.aspx [microstrain.com]

    I worked with this device last summer implementing a vehicle flight path recorder. It not only has 3 rate gyro's but three 5 mG accelerometers, a compass and processor that implements navigational processing and outputs earth-frame quantities via a serial connection.

    Size: 42 x 40 x 15 mm
  • I wonder... (Score:2, Insightful)

    by Mex (191941)
    Since they are always imagining "interesting" uses for new technology, I wonder how the porn industry will implement this technology?

    There's already adult websites made exclusively for Wii navegation...
  • Check these out. [sparkfun.com] Full six-axis IMUs for just a very few hundred dollars.

    I about wet my pants when I saw these. The last time I had checked, a few years ago, solid-state gyros (from Systron Donner, maker of the GyroChip line) were $1000 apiece.

    Thad Beier
  • 10 centimeters! (Score:4, Informative)

    by arsenix (19636) on Friday March 02, 2007 @09:34PM (#18214278)

    This guy needs to spend 5 minutes googling for IMUs (intertial measurement units).

    For instance, this unit:
    http://www.memsense.com/products/mag3.asp [memsense.com]

    There are a million of these out there...

    Has three axes of accelerometers, three axes of rate gyros and a three axis magnetometer... all in a package that is .7"x.7"x.4".
  • TFA: ...Today, such products are quite big, a cube 10 centimeters on a side. We want to do this in less than a 30-millimeter cube...

    Not sure island they have been living on, but this was actually available in the end of the previous century.

    Analog Devices and others have been selling the ADXRS150 http://www.analog.com/en/prod/0%2C2877%2CADXRS150% 2C00.html [analog.com] and many others for years.
  • by aero6dof (415422) <aero6dof@yahoo.com> on Friday March 02, 2007 @10:35PM (#18214602) Homepage
    The motion sensors aren't the unique part of the Wii. Sony's controller has the equivalent motion sensors. The unique part of the Wii is the combination of the motion sensors with the IR bar tracking to give you a non-drifting reference.

    By themselves, the motion sensors will get further and further off position. For example, if one turned right 90 degrees and then returned, the motion sensors by themselves would cause you to calculate a position not-quite matched up your original - and the more you move the more the reference will drift as measurement errors accumulate. With the IR bar, the reference can be corrected so the controller can stay oriented correctly vs the screen.

    This is why Sony's controller is a very poor substitute for the Wii controller.
  • 10cm Cube, Bull***t! (Score:3, Interesting)

    by monopole (44023) on Friday March 02, 2007 @10:47PM (#18214644)
    What utter bullshit!
    Having personally developed and packed a six axis MEMS inertial sensor (x,y,z acceleration, roll, pitch, yaw rate of rotation)into a 25x25x13mm cube (With my bare hands!!)potted in epoxy, with a rubber lining and a kevlar reinforced cord, and run 2 of these units for several hours at kilohertz rates logging onto a SD card, I can attest that 30mm cube MEMS sensors already do exist and have existed for over 5 years. Hell you can buy them in quantities of one from sparkfun:
    http://www.sparkfun.com/commerce/categories.php?cP ath=23_85 [sparkfun.com]
    (while the sparkfun units are 51x51x23mm thats because they're avoiding many layer multilayer boards and low pin count microprocessors)
    Note that 3 axis compasses are readily available as well:
    http://www.sparkfun.com/commerce/categories.php?cP ath=23_83 [sparkfun.com]

    Now the devil in the details. MEMS accelerometers are noisy, and so are the MEMS rate gyros. They're about as good as your inner ear which operates on somewhat similar principles. As a result they track reasonably well for short periods of time but exhibit considerable drift over longer periods of time, just like you can guess your path over a short distance but end up going in circles in total darkness. A compass helps, but they get scrambled by magnetic fields from electric currents or pieces of ferromagnetic material. Inertial sensors (other than missile grade units which are orders of magnitude more sensitive and complex) only complement GPS and other absolute measurement systems. That's why the Wii has the optical sensor integrated in it as well.

     
  • ok. I could be wrong, so enlighten me please. Fro the article he said he wanted to make _a_ 3 dimensional gyroscope very small. Now, all the posts here saying these things are already done smaller anyway, but listing the fact these products contain multiple gyro's / Xometer's / etc.. Is he saying he wants a single instrument to provide the measurements, as in a single gyro, not 3 or similar? or am I just plain wrong?
  • Analog Devices created the chip inside the Wiimote, and another company designed the chip inside the nunchuck. Notice the drastic difference between the two. The wiimote reacts much faster!
  • I'm doing my undergrad thesis on a high-speed autonomous vehicle that uses accelerometers to augment the refresh rate of GPS. I thought it was interesting that the article mentioned it so specifically.
  • Then I want to make a three-dimensional gyroscope

    Benedetto Vigna should read this report http://www.sciencemag.org/cgi/content/abstract/315 /5813/863 [sciencemag.org] about how moth are able to manuver so well in space. Their antennae are a small, very small device which does the job amazingly well. If first heard about this on Quirks and Quarks http://www.cbc.ca/quirks/media/2006-2007/mp3/qq-20 07-02-17d.mp3 [www.cbc.ca], a science radio programme.

    To fly we observed how birds did it, then instead, built wings as used in airplanes today

  • We want to do this in less than a 30-millimeter [on a side] cube, to serve as an image stabilizer in cameras and to track a person's position in the intervals when he can't get a GPS signal.

    Maybe he should take a look at the 6mm x 10mm x 2.5mm NEC gyro (http://www.nec-tokin.com/english/product/piezodev ice2/ceramicgyro.html [nec-tokin.com]) or at the 7mm x 4.8mm x 3.2mm Analog Devices one (http://www.analog.com/UploadedFiles/Data_Sheets/A DXRS150.pdf [analog.com]). With both of these a 3 axis gyro fits in less than 10cm^3.

  • Drastically changing the nature of team sporting events - a new way to collect new and different types of game statistics .... to make sports more competitive.

    IEEE reports "What's really interesting is where Benedetto Vigna wants to take this technology. He has plans to make the sensor smaller and tougher, and hope to place it inside of things like shoes, textiles, and medical devices to aid in data collection."

    For example in an NBA basketball game, if each player, referee and the ball contained a MEMS devi
  • > Then I want to make a three-dimensional gyroscope, to measure
    > rotation around three different axes.

    > We want to do this in less than a 30-millimeter cube, to serve as an
    > image stabilizer in cameras

    This guy can't be this clueless. Invensense has been making gyros for that purpose for years and they've been used in cameras for years. 3 axis gyroscopes already fit in 10mm cubes.

    Interesting how ST made him a general manager. Can his subordinates afford to live in houses? American companies j

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