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Hardware Hacking Science

Optical Mouse Used As Cheap Motion Sensor 131

Posted by timothy from the goldbergerism dept.
drphil writes " Dr. Tuck Wah Ng, a member of the Faculty of Engineering at the National University of Singapore uses an optical mouse as a cheap non-contact motion sensor in his research. If a resolution of a little less than 60 microns is sufficient, you really can't beat the price. Dr. Ng has studied the viscoelastic deformation of plastics using a hacked optical mouse - published in J. Chem. Ed. vol 81, p 1628, 2004. You'd need to be a subscriber of the journal to see anything but the abstract, but any university science/chemistry library would have a copy of this issue of the Journal of Chemical Education. (Viscoelastic deformation, in plain English, is the degree to which a plastic stretches when you pull on it)"
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Optical Mouse Used As Cheap Motion Sensor More

Optical Mouse Used As Cheap Motion Sensor

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  • Slashdotted already... (Score:3, Informative)

    by jonasw ( 778909 ) on Sunday November 28, 2004 @04:05PM (#10938399)
    Coralized link here [nyud.net].
    • Looks like a coralized link of a 409 error...
    • That's slashdotted too...

      This isn't all that hard to do. Just turn your mouse upside down and pass something over it. Watch the cursor move!

    • It's strange that their site would return a 409 message, which doesn't seem appropriate for the type of error that the web page shows. A forbidden code (403) I could understand, but not a conflict code.

      Although it doesn't appear this is what occurred here, I wanted to note that if Coral has an object cached (after receiving an HTTP OK - 200), then the site starts returning 404s or 503s (and some other error conditions) after the cached object expires, Coral will continue to serve the stale objects out of
    • Not so new ...

      We did this about a year ago in my Mechatronics course. We attached an optical mouse to a robot along with some various sonar and rangefinders. Using various programming and such, we had the robots driving around and identifying known shapes and such.

  • Impressive... (Score:5, Funny)

    by xNoLaNx ( 653172 ) on Sunday November 28, 2004 @04:06PM (#10938406)
    That's a nice link there, I'm sure the first 1 or 2 people who saw it may have been interested.

  • It's been done before in a much cooler application (Score:5, Interesting)

    by TurkishGeek ( 61318 ) on Sunday November 28, 2004 @04:10PM (#10938427)
    Not really new-I'm sure many Slashdotters who are IEEE members enjoyed the September 2004 issue of IEEE Computer magazine which covered the theme of biologically inspired robotics. There is a paper in that issue by S. Thakoor et al. which uses an optical mouse chip for terrain feature tracking for a flying aerial robot. You can't read the paper if you don't have IEEE digital library access, but here is the link:

    http://csdl.computer.org/comp/mags/co/2004/09/r903 8abs.htm [computer.org]

    • Cool applications (Score:2, Interesting)

      by jvervloet ( 532924 )

      Now that we are talking about /cool/ applications using simple computer hardware...

      In our coffee room, the switch of the fridge light is connected to the F11 key of a keyboard. If you open the fridge without entering a correct access code (using the same keyboard), there is an alarm :-)

      Too bad that there aren't any photos on-line of this hi-tech fridge intrusion detection system...

    • I had a great idea about using optical mice last year. I was going to take one down to my electric meter, so I could get a realtime reading of power consumption as the wheel on the meter rolled by.

      So I went out to my meter and damned if they hadn't replaced it with a digital display.

      Buggers!
      • Those new meters would sometimes come with a pulsed digital binary output. You connect that output terminal to a controller/computer and read the pulse. Each pulse is like 1/2 kilowatt hour. You can easily rig something up to read the power consumption.

  • Can it be done for cell counting? (Score:3, Interesting)

    by Linuxathome ( 242573 ) on Sunday November 28, 2004 @04:12PM (#10938436) Homepage Journal
    I wonder if the sensor can be used to create cheap cell counting devices. It could be used say in the clinic for a quick complete cell count (wouldn't be able to distinguish the different types of cells, but could still prove useful). Or in other areas, it could be used to count beads (nano beads).

    • Re:Can it be done for cell counting? (Score:5, Informative)

      by Anonymous Coward on Sunday November 28, 2004 @04:22PM (#10938484)
      60 microns is too low a resolution for that purpose.

    • It could be used say in the clinic for a quick complete cell count

      Even if it could, what would be the point? The cost of FDA approval would by far outweigh any savings by using such a sensor and since it's being used so far outside its intended purpose, you'd have to start a separate project just to do the validation so you could incorporate it into your instrument.

      That said, it is a cool idea if it could be made to work as there are many other small particles that need to be counted other than blood c

  • I pity all the students.. (Score:3, Funny)

    by Anonymous Coward on Sunday November 28, 2004 @04:13PM (#10938440)
    ..who are trying to use this server's enrollment system just right now.

  • Slashdotted, but... (Score:4, Informative)

    by MrNonchalant ( 767683 ) on Sunday November 28, 2004 @04:15PM (#10938449)
    Well, I can't access the page currently but if it is what I think it is this has already been done. A high school student I knew built a optical mouse motion sensor as a project. It tracked the floor, and could be used as a human-interface controller for a robot or as the robot's position tracking mechanism.

    He interfaced it to a microcontroller as well, which was the real difficult part. PS2 to a serial port, then the software to interpret it. Unfortunately the thing was handicapped by the 8 bit memory, but it was still pretty darn cool.

    This was part of Andrew's Leap, a program sponsored by CMU and taught by professors to a select few high school students. Hopefully what this doctor has done is a bit more complicated.

  • Dr. Tuck Wah Ng (Score:1, Funny)

    by Anonymous Coward
    Just how is "Wah Ng" pronounced...?

  • A similiar hack (Score:5, Funny)

    by Anonymous Coward on Sunday November 28, 2004 @04:16PM (#10938457)
    Researchers looking into the hearing of flies attach the fly to a fixed support above it, and allow it's feet to touch a ping pong ball dotted with sharpie-marker dots. The ball rests on an optical mouse with some foam to hold it in place. By playing sounds from different directions and measuring where the fly moved in reaction they where able to determine how directionally-accurate the hearing of the fly was.

    This is all per some TV show, maybe Discovery's This Week

  • Fun experiment (Score:5, Interesting)

    by TrentL ( 761772 ) on Sunday November 28, 2004 @04:16PM (#10938459) Homepage
    If a resolution of a little less than 60 microns is sufficient, you really can't beat the price

    Hmmm. This inspired me to try to see if I could move my optical mouse without moving the cursor. It's possible, but very difficult. It obviously depends on the sensitivity setting.
    • /etc/init.d/gpm stop

    • Re:Fun experiment (Score:2, Insightful)

      by Anonymous Coward
      Thing is that it's not really limited by the resolution of the mouse but by the screen's resolution. If the screen only has 1280 columns you simply won't see the cursor moving even if the mouse told the computer "hey move!"

    • Re:Fun experiment (Score:4, Funny)

      by scribblej ( 195445 ) on Sunday November 28, 2004 @04:42PM (#10938583)
      Did you try picking it up first? Works for me...

      heh!

    • you probably just rotated it

    • Re:Fun experiment (Score:5, Interesting)

      by Spy Hunter ( 317220 ) on Sunday November 28, 2004 @11:47PM (#10940426) Journal
      In Robotics class some classmates and I made a robot that used an optical mouse to sense how far it had driven across the floor. We found that the accuracy of our optical mouse left a lot to be desired. The actual distance sensed by the mouse changed depending on the speed it moved across a surface (and didn't seem very accurate even after taking this into account). For normal use this doesn't matter a bit, because you get feedback from the movement of the mouse pointer on the screen, not from the absolute position of your hand on the mouse pad. However, for our robot, this meant that it quickly went off track. It couldn't even drive in a reasonable square on the floor. So it's fine to use optical mice to measure the presence of and probably also the direction of small-scale motion, but using them to measure absolute speed or distance on medium to large scales is not adviasble.
    • This can happen easily and accidentally!

      I have frequently and unintentionally managed to move my optical mouse without moving the mouse cursor. I use my notebook (with a small optical USB mouse) on top of a glass table. I actually have to *remember* to put something under the optical mouse!

  • Not surprising (Score:3, Interesting)

    by sodul ( 833177 ) on Sunday November 28, 2004 @04:18PM (#10938467) Homepage
    I'm not surprised that regular or optical mouses are used for something else than moving a cursor on the screen. I had a Path Finder Robot [odul.com] project back in 1998.
    It was a very dumb small robot but it had to be able to move forward, backward and rotate, which needed some way to estimate distaances. And the cheapest way of doing it was to put a mouse underneath.
    Basicaly a mouse is a tool to measure delta's (differences in distances), the optical ones are doing it very accuratly and without actual contact. That's why it's a good tool in that case.

  • What happened to mail order electronics? (Score:4, Interesting)

    by RealProgrammer ( 723725 ) on Sunday November 28, 2004 @04:21PM (#10938480) Homepage Journal

    You used to be able to order optical sensors and other generic components by the box for less than the cost of a mouse.

    I haven't checked lately, but why is it cheaper to hack a mouse than build a simple circuit?
    [Sound of luser googling ...]
    Hmmm, maybe it is cheaper.

    I can't find prices at places like http://www.aromat.com/pcsd/product/sens/select_mot ion.html [aromat.com] , so maybe "if you have to ask the price, you can't afford it".

    • Re:What happened to mail order electronics? (Score:5, Insightful)

      by kfg ( 145172 ) on Sunday November 28, 2004 @04:40PM (#10938571)
      Well, an optical mouse is actually a rather complex piece of work that goes a bit beyond a sensor (which in the case of a mouse is actually a minicam), just pull the circuit board from one and have a look. Then add in the cost of the plug, wire, etc.

      Mice are cheap, and you can use the time you would have spent designing and building a data acquisition unit doing your real work.

      Where I can't get what I want, or where what I want cost thousands of dollars when I can build it myself, better, for ten, I build, and I'm glad to do it.

      When I can buy what I need off the shelf for twenty five dollars, or spend a week designing and building it myself for twenty dollars, well, I usually just go buy the sucker (unless I'm simply smitten by the intellectual challange of the thing for some reason).

      But here is what I suppose is the biggest reason for using the mouse:

      The software is already written, so you can just plug it in and it works.

      KFG
    • You used to be able to order optical sensors and other generic components by the box for less than the cost of a mouse

      Yea, and my first ball mouse cost me over $75. Last week I got an optical mouse free, after rebate. Do you expect a mail order house to supply you with a box of sesors and other generic components for less than that?

  • Plastic? (Score:2, Funny)

    by snotman88 ( 829679 )
    What plastic was he testing? Was it his mouse cable?

  • $10 Thermal Imager from a porch light (Score:5, Informative)

    by N8F8 ( 4562 ) on Sunday November 28, 2004 @04:22PM (#10938482)
    I was looking for an inexpensive option for thermal imaging and I came across this project for a $10 thermal imager [bestweb.net] using a automatic porch light and a frensel lense.

    Footprints project overview [ibm.com]

  • not to be picky or anything.... (Score:5, Informative)

    by carambola5 ( 456983 ) on Sunday November 28, 2004 @04:22PM (#10938483) Homepage
    but "motion" cannot be described in "microns." I think you mean "cheap displacement sensor".

    And viscoelasticity is not necessarily a plastic-related thing. Some metals and composites may strain in a viscoelastic manner. Biological tissue is also generally deemed viscoelastic. Basically, it means: the amount of stress in the material is proportional to the rate at which it is displaced (or strained, in more correct terms).
    • Actually, viscoelastic is a combination of viscous and elastic (obviously) which means that the stress in a material is a combination of the rate and amount of strain.
    • From the abstract (emphasis added):
      For accurate and quantifiable data on the deformation,
      an electronic displacement sensor should be incorporated. Most of such sensors are expensive. Here, an optical mouse was demonstrated to provide accurate data at low cost.
      I'd say the author knew that...

  • Slightly pedantic, but.. (Score:5, Insightful)

    by oexeo ( 816786 ) on Sunday November 28, 2004 @04:26PM (#10938501)
    Optical Mouse Used As Cheap Motion Sensor

    Isn't this what mice do already?

  • Subscription Only Science = evil (Score:4, Insightful)

    by nurb432 ( 527695 ) on Sunday November 28, 2004 @04:30PM (#10938520) Homepage Journal
    Just another way to restrict the flow of publicly funded research.

    Schools get tax dollars, therefore the results of any research should be freely available to the public, unless its some sort of classified governmental stuff...

    Restricting knowledge only serves to retard growth, and keep the 'special ones' in power.

    • Re:Subscription Only Science = evil (Score:1, Insightful)

      by Anonymous Coward
      Uh... dude, this was at the UNIVERSITY OF SINGAPORE.

      So what Tax Dollars are you talking about?

    • Re:Subscription Only Science = evil (Score:5, Informative)

      by norton_I ( 64015 ) <hobbes@utrek.dhs.org> on Sunday November 28, 2004 @04:57PM (#10938626)
      Restricting knowledge only serves to retard growth, and keep the 'special ones' in power.


      The results are public, just not the copyrighted article. Since tax dollars do not go to the journals, they charge for subscriptions -- print or electronic.

      That said, most scientists I know are frustrated by this as well, and do what they can to allow freer access to their work. So, if you want access to almost any scientific article, try the following (in order):

      1) Go to the author's web page. Most journals allow authors to put copies of their papers online, and many scientists take advantage of this.

      2) Go to a nearby university library. If they don't subscribe to the journal in question, ask a librarian, it may be possible to get it from another university.

      3) Go to arxiv.org (formerly xxx.lanl.gov). Many articles are published there as preprints, but may or may not be the final published version.

      4) Finally, email one of the authors. In all liklihood, they will be happy to send you a PDF of their article if it is not available via another mechanism.

      The restrictions on the dissemination of scientific literature do not stop anyone with even a tiny bit of motivation. Also, a few journals require subscriptions, but allow google to index the full text, which means the whole article may be in google's cache.
    • Restricting knowledge only serves to retard growth, and keep the 'special ones' in power.

      Giving people the knowledge that the "special ones" have power over them won't change that fact, it will just frighten them and laws will be passed to restrict research. As long as material is free to move throughout the community that understands its implications you won't be retarding growth. If you want to get access to this kind of material you should hope you have an educational system that allows people to en
    • Restricting knowledge only serves to retard growth, and keep the 'special ones' in power.

      You repeat yourself. You already said "retard growth".
  • They've built a better mouse trap - for humans! Now, Slashdotter,s beat down the bridge to their door, before the world beats a path, and never escapes!

  • "MouseField" (Score:4, Interesting)

    by dlleigh ( 313922 ) on Sunday November 28, 2004 @04:34PM (#10938547)
    "MouseField" is another project that does motion sensing with an optical mouse. They combine an RFID reader with an on-the-shelf optical mouse (or two) and do some cool user interface tricks.

    Read about it here [mobiquitous.com]. The work was presented at Ubicomp 2004 [ubicomp.org] a couple of months ago.

  • Looks like.... (Score:3, Funny)

    by rune2 ( 547599 ) on Sunday November 28, 2004 @04:36PM (#10938551) Homepage
    their webserver has undergone Viscoelastic deformation

  • creation (Score:4, Funny)

    by Doc Ruby ( 173196 ) on Sunday November 28, 2004 @04:36PM (#10938553) Homepage Journal
    any university science/chemistry library would have a copy of this issue of the Journal of Chemical Education

    Not Bob Jones university. On the 2,253,532nd day, God created the optical mouse, and thou shalt not play God, except on TV with an (800) number subtitle for donations.
    • On the 2,253,532nd day, God created the optical mouse

      You and your damned science!

      Sure, I'll bet you thought no one would do the math....

      The number of days you give... Comes out to 166 years longer than has passed since the creation!

      Blasphemer!

  • WebCams (Score:4, Interesting)

    by squoozer ( 730327 ) on Sunday November 28, 2004 @04:42PM (#10938581)

    I've seen quite a few papers recently that talk about using multiple cheap (<£30) webcams to do gesture recognition. Ok the images aren't great but the improvements you get from using £1000+ video set-ups with fancy lenses etc aren't that great.

  • Dr. Ng (Score:2, Funny)

    by Anonymous Coward
    "Here's a quarter, buy yourself a vowel."

    A shiny for the first person to get that one.
    • paraphrased from john candy in uncle buck, i'm guessing.

    • Re:Dr. Ng (Score:4, Informative)

      by tangent3 ( 449222 ) on Sunday November 28, 2004 @09:40PM (#10939928)
      It's a pretty common surname used here in Singapore and in its original form it's a word in one of the Chinese dialects. It's actual pronounciation is something like "urn", replacing the 'n' with an 'ng' where the tongue remains stationary instead of moving up to touch the ceiling of your mouth.

  • Your library may also have a password for the site (Score:3, Interesting)

    by ahecht ( 567934 ) on Sunday November 28, 2004 @05:55PM (#10938908) Homepage
    Check with you local library, they may be able to give you a password for logging in to the journal link in the article. I know mine did.

  • Nokia phone games... (Score:2, Interesting)

    by Lispy ( 136512 )
    Allthough this might be slightly offtopic:
    There are games for Nokia mobile phones that use the built in camera as a motion tracker. So you can control the cursor by moving the phone. Looks pretty weird, though.

  • Usefulness of non-optical mice, too (Score:3, Informative)

    by G4from128k ( 686170 ) on Sunday November 28, 2004 @07:09PM (#10939299)
    Old style mice (with mouse balls and encoder wheels) can also be used in scientific experiments. A bit of hacking can get the sensor and encoder wheel mounted to a shaft or to watch the slots of a homemade encoder disk (a laser printer and transparency material makes a good disk). Any basic software that can monitor mouse movement can be used to count revolutions of the wheel (just turn off mouse acceleration to get absolute mouse movement in encoder ticks). One old PC can measure 2 axes of motion for animal activity studies, windspeed & direction, robotics, etc.
  • Could it also be used for scanners? It would make it way more practical to see exactly where it is. This might even be used for a led handheld scanner. Especially if one would put 2 of these (laser powered) optical detectors on both sides.

    You read it here first (I hope).

  • This calls for Google Scholar (Score:5, Informative)

    by DaoudaW ( 533025 ) on Sunday November 28, 2004 @09:41PM (#10939930)
    Searching Google Scolar [google.com] for "optical mouse motion sensor Ng" provides some useful information. The PDFs are slashdotted like others have mentioned, but the "View as Html" pages are the google cache. The graphs are worthless, but the text is all there.

  • How about using mouse for accelerometer? (Score:5, Interesting)

    by Goldenhawk ( 242867 ) on Sunday November 28, 2004 @11:38PM (#10940385) Homepage
    This got me thinking... me and my geek engineer brain...

    Seems to me by mounting a small mass between springs right above the sensor, you could probably measure acceleration fairly accurately. The spring deflection would be precisely related to the acceleration, the mass, and the spring constant, two of which are known (or can be measured independently) and are fixed values.

    F=ma, where force = mass times acceleration
    F=kx, where force = spring constant times displacement
    so
    a = kx/m
    (Figuring out the units is left as an exercise for the reader.)

    So as the combined mouse/spring/mass assembly was accelerated, the cursor would deflect accordingly. Calibration would be straightforward: since k is fairly linear for most springs (within small ranges), and m is fixed, simply turning the sensor on its side (e.g., subjecting it to exactly 1.0g) gives a very nice data point.

    Might be a cheap and fun way to build a sensor, say for measuring cornering force on your car, etc. Also might be a neat high school physics class experiment.

    That is, unless Microsoft already patented that use... *grin*
    • cheap and fun way to build a sensor

      Perhaps. But you can also buy accelerometers for the same purpose directly from the manufacturer's (Analog Devices) website for $12 in single units.
        • But you can also buy accelerometers for the same purpose directly from the manufacturer's (Analog Devices) website for $12 in single units.

        Sure. But does that include a computer interface that doesn't require custom hardware and software, can be easily understood by any computer user, and can be easily programmed in Visual Basic or a dozen other languages?

        Yes, it's quite possible to buy low-cost sensors. The beauty of using a mouse as the basis for a sensor is its ready-to-use nature.

  • ...but I'm certain we all already knew what viscoelastic deformation is!
  • Back in the day, when I did Signal Processing at uni, the signals were captured/sampled by a Soundblaster 16 Line In.

    Another case of University people being ingenious as they are wont to do.

  • Non-contact sensors are widely used in scientific motion sensing. Such sensors typically work on the principles of ultrasonic, optical, Hall effect etc.. Non contact sensors are generally expensive due to either the high accuracy required or the limited number of pieces that are produced. The optical mouse was developed by Agilent Technologies in 1999 to overcome the limitations of the mechanical mouse. But is the optical mouse merely a pointing device? What if the optical mouse could be applied to scientif

  • Mouse photographing what's underneath it (Score:3, Interesting)

    by sonamchauhan ( 587356 ) <sonamc.gmail@com> on Monday November 29, 2004 @07:45AM (#10941588) Journal
    An optical mouse is essentially an optical camera combined with an onboard DSP chip that processes the stream of images and generates mouse coordinates. So, I got thinking, hey, given enough passes over whatever serves as your mousemat, you could build an image of it!

    I remember taking a look at spec sheets for one or two optical mouse sensor chips. The sensor is generally pretty low res (30x30 pixels or something similar),but has an astounding frame rate (500 or 2000 fps or something like that) . However, the IC had a instruction that caused it to dump the full image back to mouse controller (the host PC theoretically). So, as long as nothing in the mouse hardware controller itself stopped it, it would be possible to write an OS mouse driver that accessed these raw images.

  • Did anyone notice on Dr. Ng's webpage about the invention of the optical mouse? The text states, as well as the two links he provides, that the optical mouse was invented by Agilent in 1999. Umm... I guess the Genius optical mouse I bought for my Amiga in 1995 was a figment of my imagination? (it was switchable between PC, Mac, and Amiga/Atari protocols... ah, the days) And the fact that I bought it USED and abused? And that I had wanted an optical for years before that (since 1990 IIRC; I think I remem

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