Optical Mouse Used As Cheap Motion Sensor

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)"

Comments

It's been done before in a much cooler application

[TurkishGeek]

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

Can it be done for cell counting?

[Linuxathome]

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).

Fun experiment

[TrentL]

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.

Re:Fun experiment

[Spy Hunter]

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.

Not surprising

[sodul]

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 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?

[RealProgrammer]

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 , so maybe "if you have to ask the price, you can't afford it".

"MouseField"

[dlleigh]

"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. The work was presented at Ubicomp 2004 a couple of months ago.

WebCams

[squoozer]

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.

Cool applications

[jvervloet]

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...

Your library may also have a password for the site

[ahecht]

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.

Re:not to be picky or anything....

[Bill Barth]

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.

Nokia phone games...

[Lispy]

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.

for less than the cost of a mouse

[frovingslosh]

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?

Got an old-style electric meter on your home?

[skids]

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!

Re:Got an old-style electric meter on your home?

[lashi]

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.

How about using mouse for accelerometer?

[Goldenhawk]

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*

Mouse photographing what's underneath it

[sonamchauhan]

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.

Re:Subscription Only Science = evil

[geeber]

Go to Optics Express and you will see an example of a reputable online scientific journal in action. Optics Express is becoming one of the most cited journals in the Optical Science community. It is peer reviewed and completely free to read. It is supported by publication page charges - i.e. the authors pay to have their work published in the journal.