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Optical Mouse Used As Cheap Motion Sensor
Posted by
timothy
on Sun Nov 28, 2004 03:03 PM
from the goldbergerism dept.
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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Slashdotted already... (Score:3, Informative)
Re:Slashdotted already... (Score:2, Informative)
Re:Slashdotted already... (Score:2)
This isn't all that hard to do. Just turn your mouse upside down and pass something over it. Watch the cursor move!
Impressive... (Score:5, Funny)
It's been done before in a much cooler application (Score:5, Interesting)
http://csdl.computer.org/comp/mags/co/2004/09/r90
Cool applications (Score:2, Interesting)
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...
Got an old-style electric meter on your home? (Score:3, Interesting)
So I went out to my meter and damned if they hadn't replaced it with a digital display.
Buggers!
Re:Got an old-style electric meter on your home? (Score:3, Interesting)
Can it be done for cell counting? (Score:3, Interesting)
Re:Can it be done for cell counting? (Score:5, Informative)
Parent
I pity all the students.. (Score:3, Funny)
Slashdotted, but... (Score:4, Informative)
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.
A similiar hack (Score:5, Funny)
This is all per some TV show, maybe Discovery's This Week
Re:A similiar hack (Score:3, Informative)
Re:A similiar hack (Score:3, Informative)
Alan Alda is the host on that...
HTH.
BMO
Fun experiment (Score:5, Interesting)
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.
Re:Fun experiment (Score:2, Insightful)
Re:Fun experiment (Score:4, Funny)
heh!
Parent
Re:Fun experiment (Score:5, Interesting)
Parent
Not surprising (Score:3, Interesting)
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)
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)
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
Parent
for less than the cost of a mouse (Score:3, Interesting)
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)
Re:Plastic? (Score:2, Funny)
Re:Plastic? (Score:2)
$10 Thermal Imager from a porch light (Score:5, Informative)
Footprints project overview [ibm.com]
not to be picky or anything.... (Score:5, Informative)
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).
Re:not to be picky or anything.... (Score:3, Interesting)
Slightly pedantic, but.. (Score:5, Insightful)
Isn't this what mice do already?
Re:Slightly pedantic, but.. (Score:4, Funny)
Parent
Subscription Only Science = evil (Score:4, Insightful)
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:5, Informative)
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.
Parent
Re:Subscription Only Science = evil (Score:3, Interesting)
Re:Subscription Only Science = evil (Score:2, Insightful)
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
Re:Subscription Only Science = evil (Score:2)
You repeat yourself. You already said "retard growth".
Say "cheese"! (Score:2)
"MouseField" (Score:4, Interesting)
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)
creation (Score:4, Funny)
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.
WebCams (Score:4, Interesting)
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)
A shiny for the first person to get that one.
Re:Dr. Ng (Score:4, Informative)
Parent
Your library may also have a password for the site (Score:3, Interesting)
Usefulness of non-optical mice, too (Score:3, Informative)
This calls for Google Scholar (Score:5, Informative)
How about using mouse for accelerometer? (Score:5, Interesting)
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*
Mouse photographing what's underneath it (Score:3, Interesting)
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.
Re:already... (Score:5, Funny)
Parent
Re:i didnt rtfa (Score:3, Funny)