The Mechanics of Motion Sensing

Dr. Eggman writes, "The AP has a short technology piece on the mechanics that go into the motion-sensing capabilities of the Wii and PS3 controllers. It also details some of the past uses of the technology and gives a nice overview of just how far the technology has come from the earliest missile-guidance sensor equipment."

Comments

Interesting.

[Mendak Jemuna]

Interesting, but I have one question. Do the silicon springs recalibrate every so often, or will they wear out and break? My old N64 controller did this.

Re:Interesting.

[drinkypoo]

They're so minute and move so little you will never have to worry about them breaking. Because they are so tiny you can never build up appreciable inertia in them. They are functionally considered solid state devices and they should last pretty much forever.

Re:Interesting.

[indigest]

"Silicon spring" is misleading because it implies there are moving parts within the accelerometer that can break. In actuality, the proof mass is held perfectly still using a feedback loop to cancel the externally applied force. The magnitude of this applied force is read out as the acceleration. No calibration is ever needed thanks to the feedback loop.

Re:Interesting.

[Plutonite]

It is not held perfectly still in both piezoresistive and capacitive accelerometers. You need to have displacements to measure the acceleration, and stiction is the problem solved with feedback/force units.

Or maybe I just misunderstood you..

Re:Interesting.

[fatphil]

Should - and do. One of Freescale Semiconductor's clients' more popular uses for accelerometers is in industrial applications -- BIG kit -- on things that vibrate constantly. Things that vibrate more and more as bearings dry or wear (hence the need for the accelerometer - so you can perform detect this and perform maintenance before your printing press, or whatever, self-destructs). The accelerometers outlive any of the parts they are supposed to look after.

Freescale has some pretty cool electonmicrographs of their 2-axis and 3-axis accelerometers - www.freescale.com, sensors, accelerometers, and browse around - I can't actually find the images now. I have a PPT on my work laptop, but that's no use. Grab a ZSTAR for <$50, and simply have a play with one yourself - (that includes everything - hardware and development kit).

Re:Interesting.

[naoursla]

I asked a MEMS researched about this once. He said it comes down to fatigue. If you bend a paperclip back and forth a bunch of times the metal fatigues and eventually breaks. Fatigue occurs because the metal actually migrates around the bend. MEMS components are so small and move so quickly that they do not rest in one position long enough for fatigue to occur. The same principle hold for the springs in accellerometers and the mirrors in DMD projectors.

Re:Interesting.

[cachimaster]

Nice article, but for the technical inclined, here are one product page, including datasheets, etc.
From one of the datasheets: Max. acceleration supported: 3000 G for 0.5s, 10000 G for 0.1s.
Good luck breaking that one.

Re:Interesting.

[EmbeddedJanitor]

Most accelerometers can survive 3000G or so.

Re:Interesting.

[Alizarin Erythrosin]

Sure, they can survive that, but most of their electronics that process it can't handle that many G's and get saturated.

Re:Interesting.

[DerekLyons]

"Silicon spring" is misleading because it implies there are moving parts within the accelerometer that can break. In actuality, the proof mass is held perfectly still using a feedback loop to cancel the externally applied force. The magnitude of this applied force is read out as the acceleration. No calibration is ever needed thanks to the feedback loop.

Actually - you are only partly right. You still need to calibrate the device in order to determine what magnitude of applied (feedback) force correlates to what magnitude of applied acceleration. (Which I doubt they do for the Wii-mote, as it probably doesn't need that level of accuracy.)

Re:Interesting.

[kilraid]

I don't buy this explanation. Say you accelerate a missile, you will have a considerable duration of acceleration, imposing a force upon the MEMS (micro-electro-mechanical systems) components. Yet they survive it.

Re:Interesting.

[AcidLacedPenguiN]

I dunno... some people get pretty violent with their wiis.

Re:Interesting.

[naoursla]

Good point. The original question I asked was in reference to the mirrors on a DMD device. Maybe the same principle does not hold for accellerometers.

Re:New major security hole found in Linux

[Tainek]

Oh God Mine Eyes!!!!!11

(Yeah even if i had been stupid enough to click it, Im de-sensitised by now anyways)

SkinnerBox 2k7

[American AC in Paris]

It also details some of the past uses of the technology and gives a nice overview of just how far the technology has come from the earliest missile-guidance sensor equipment."

See, I think we should re-incorporate early guidance systems into modern-day game controllers.

I mean, think about it: game controllers with trained pigeons in 'em! That'd take force-feedback to a whole new level!

Re:SkinnerBox 2k7

[rantingkitten]

The missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't.

They missed this game system

[Joe The Dragon]

Globalvr's new Ultrapin features Globalvr's Patent Pending U-Shock Board Which allows players to interact with the cabinet for a totally realistic pinball experience. You can BUMP and NUDGE the cabinet to affect the ball in play - just like real pinball
http://www.globalvr.com/products_ultrapin_intro.ht ml

Other applications

[inKubus]

It would be cool to incorporate this type of controller into a portable device. You could have portable laser-tag like games with real-time mapping, or incorporate some type of ball and it automatically keeps score and records the game. You could have "operations" players indoors that have some different role (view the maps, for instance, and direct the players)

With networking and GIS in a portable device, it's almost necessary to have new interfaces to use all the new space it knows about. In gaming it's the most fun but these types of thing could be used in more professional ways also.

Re:Other applications

[MankyD]

It would be cool to incorporate this type of controller into a portable device. You could have portable laser-tag like games with real-time mapping

While it would definitely be cool, you can't really use accelerometers as location devices. Accelerometers and, to a lesser degree, odometers both do a pretty terrible job of keeping track of where an object is located. That's why the Wii also includes a sensor bar.

They'll generally give you pretty good readings for a single movement, like 'the object just moved 1 meter forwards', however as soon as you turn or travel a long distance, they suffer from drifting, skidding, and general measurement errors.

A different sort of tech would be needed for mapping. You can do some research into Robotics, such Markov Localization, for some more information. GPS and related techs are better for real time location reporting.

Re:Other applications

[justkarl]

That makes sense. Dosen't Wii come with wireless networking built-in? Or am I confusing it with the PS3?

Re:Other applications

[Anonymous Coward]

It would be cool to incorporate this type of controller into a portable device. You could have portable laser-tag like games with real-time mapping, or incorporate some type of ball and it automatically keeps score and records the game. You could have "operations" players indoors that have some different role (view the maps, for instance, and direct the players)

With networking and GIS in a portable device, it's almost necessary to have new interfaces to use all the new space it knows about. In gaming it's the most fun but these types of thing could be used in more professional ways also.

Like this?

Pacman comes to life virtually

http://www.mixedrealitylab.org/

http://www.mixedrealitylab.org/index.php?option=co m_content&task=view&id=42&Itemid=36

Re:Other applications

[DerekLyons]

It would be cool to incorporate this type of controller into a portable device. You could have portable laser-tag like games with real-time mapping

While it would definitely be cool, you can't really use accelerometers as location devices.

I guess then all those inertial guidance and navigation systems the military has deployed don't really work then? (Or, IOW, you are incorrect. Considerably.) Accelerometers by themselves can't be used as location devices - but if you use a clock and a computer and integrate acceleration over time..., they work just dandy. (For real-world use, you need a stable platform (I.E. gyros) as well.)
 
 

They'll generally give you pretty good readings for a single movement, like 'the object just moved 1 meter forwards', however as soon as you turn or travel a long distance, they suffer from drifting, skidding, and general measurement errors.

That's true of odometers, but again with accelerometers it's just a matter of engineering your system properly. (The USAF equips its fighters with inertial navigation systems - and they remain accurate through a bloody dogfight!.)
 
 

A different sort of tech would be needed for mapping. You can do some research into Robotics, such Markov Localization, for some more information. GPS and related techs are better for real time location reporting.

I suggest that you do some research on inertial navigation and inertial guidance - because what you say is true at the level of the casual gamer, its not true (as you imply) of accelerometers in general.

Re:Other applications

[dcam]

They'll generally give you pretty good readings for a single movement, like 'the object just moved 1 meter forwards', however as soon as you turn or travel a long distance, they suffer from drifting, skidding, and general measurement errors.

That's true of odometers, but again with accelerometers it's just a matter of engineering your system properly. (The USAF equips its fighters with inertial navigation systems - and they remain accurate through a bloody dogfight!.)

No the OP was right. It is also true of accelerometers. And the fact that they are measuring data during a dog fight it irrelevant, it is the amount of time/distance they are measuring data. They include a random walk error that is small for a short time/distance, but compounds over time.

You will find that typically this is corrected with something that can give an absolute position (eg GPS). Your absolute positioning device typically also has a know error. The values from both of these are generally married using a Kalman Filter or Extented Kalmna Filter.

I've written code to do this in the past.

I suggest that you do some research on inertial navigation and inertial guidance - because what you say is true at the level of the casual gamer, its not true (as you imply) of accelerometers in general.

I suggest that you also do some. 4 years of Mechatronic Engineering would be good start.

Re:Other applications

[big tex]

4 years of Mechatronic Engineering would be good start.

OK, you made that up.
It sounds like you design robotic enemies for Godzilla.

Re:Other applications

[dcam]

No. Click the about Us link at the bottom of the page.

But yes it does mean robots.

Re:Other applications

[dcam]

Trying that again, should have previewed.

No. Click the about Us link at the bottom of the page.

But yes it does mean robots.

Re:Other applications

[Animats]

Low-end solid state accelerometers aren't that good. Accuracy is only 1% or so. You can't really get position by integrating them twice; you'll get huge amounts of drift as false velocity builds up. If you have some external reality check, even an odometer, you do much better.

Low-end rate gyros aren't that good either. We did badly in the DARPA Grand Challenge because our heading measurements were about +-3 degrees off, which was enough to mess up the maps being built up from the laser rangefinder. We should have spent the $20,000 for a fibre optic rate gyro, like the more successful teams. (Today, they're down to around $2000-$3000).

Re:Other applications

[KDR_11k]

Naah, it's Computer Science, Mechanic and Electronic Engineering. Not as in-depth as either of these but the versatility is needed in some areas, e.g. automobile design. Or designing robotic enemies for Godzilla. Except you don't need stop motion or Cg to make them move.

Re:Other applications

[dcam]

Cool. It looks like the ACFR, where I did my BE, has been involved in DARPA. I haven't been in contact with any of them since I left uni, so I don't know what the project is. It isn't surprising that UTS is involved, the guy who heads UTS's Mechatronics dept is a former ACFR man.

The ACFR has for some time had a bit to do with vehicles. The've used a UTE as a testing platform for a while. Most of their work has been to do with industry, mining trucks and straddle carriers. They've done some solid work though.

Re:Other applications

[DerekLyons]

No the OP was right. It is also true of accelerometers. And the fact that they are measuring data during a dog fight it irrelevant, it is the amount of time/distance they are measuring data. They include a random walk error that is small for a short time/distance, but compounds over time. You will find that typically this is corrected with something that can give an absolute position (eg GPS). Your absolute positioning device typically also has a know error. The values from both of these are generally married using a Kalman Filter or Extented Kalmna Filter.

Here's a free clue for you, since you seem to need one so badly. Try actually reading my message and think real hard on what the words means. (Hint: Concentrate on the terms "engineering your system properly". What do you think they means?)
 
 

I suggest that you also do some. 4 years of Mechatronic Engineering would be good start.

I've got more than sufficient education on inertial systems, when you get out of high school, look me up.

Re:Other applications

[dcam]

Haha thanks for the lesson. Love the ad hominem attack.

I've got more than sufficient education on inertial systems...

Clearly not. ...when you get out of high school, look me up

Gee, somehow I forgot to look up up 10 years ago, how remiss of me.

Ok I'll make it simple for you, so that with some high school physics and some elementary logic you can understand.

Lets being by assumimg you aren't an idiot and use SI units.

All sensors have some error. So lets take an example. I have a accelerometer, with a 0.1 m/s/s error that isn't moving (to make life simpler). To get a speed you need to integrate (multiply by time), to get position you need to integrate twice.

Lets also say you are taking measurements every second (slow I know, but this is an example and I want it to be simple).

With that error after one measurement you know both speed and position with an accuracy of 0.1 m/s and 0.1m respectively (+/-), over 1000 measurements, you know your speed and position to within 100 m/s and 100 m respectively (+/-). That is pretty large.

So say we introduce something that has a large error (like GPS), but is give absolute measurements like say GPS or an odomoter. GPS has an error (now that the noise is switched off) of +/-10m. Well gee over 1000 seconds that is pretty darn good when compared 100m over 1000 seconds. On the other hand over 1 second that is pretty bad. So you use a Kalmal Filter to combine the values. This corrects the error introduced by the Interial Navigation System (INS).

No matter how well "engineered" your system is you cannot escape the fact that interial sensors (gyros are Inertial too BTW) contain error (like all sensors do), but in the case of INS, the error compounds. You may be able to engineer a system so that the compound error is acceptable, but you cannot escape the compound error. So in essence, you don't know what you are talking about. Why don't you just pull your head and admit that you were wrong?

Re:Other applications

[AcidLacedPenguiN]

Most importantly, you could have real time weapon switching!!!

Re:Other applications

[Anonymous Coward]

My post from last night appears to have been deleted for some unknown reason. Lets try this again:

It would be cool to incorporate this type of controller into a portable device. You could have portable laser-tag like games with real-time mapping, or incorporate some type of ball and it automatically keeps score and records the game. You could have "operations" players indoors that have some different role (view the maps, for instance, and direct the players)

With networking and GIS in a portable device, it's almost necessary to have new interfaces to use all the new space it knows about. In gaming it's the most fun but these types of thing could be used in more professional ways also.

You mean like this?

Pacman comes to life virtually

http://www.mixedrealitylab.org/index.php?option=co m_content&task=view&id=42&Itemid=36

http://www.mixedrealitylab.org/

Hopefully this post won't get deleted (or eaten by slashdot-perl bugs) this time. Though its a bit late now and I doubt it will be seen by the parent poster.

Re:Other applications

[glindsey]

Dude, Mechatron was my favorite Transformer!

Seriously, though, I had no idea "mechatronic engineering" was a discipline. Fascinating...

Re:Other applications

[dcam]

When I started my undergraduate degree (1997) it was kind of new. It had been started only 4 years before. At that point you began doing Mechanical Engineering and after 1 year had the choice of transferring into to Mechatronics, ie there was no first year for mechatronics. For the second year, it was identical to Mech Eng, except you dropped Materials for a dedicated Mechatronics subject. After that it tended to diverge quite a bit.

Now it is a completely separate degree from the first year. It also needs better marks to get into and tends to attract brighter students.

Effectively it still has a lot in common with Mechanical Engineering, but you drop a lot of materials, fluid flow and thermodynamics in favour of more Electrical Engineering. You also tend to do far more programming. You could get through a Mech Eng degree while being uncomfortable with coding. Not so with Mechatronics.

Perhaps the kind of degree it is is best illustrated by a couple of the final year subjects. We were given a 16 bit intel microprocessor on an evaluation board and given a number of tasks to program in assembler, stuff like generating light patterns, talking down the serial port etc. Then to redo the projects in C. All of this would involve handling interrupts and working with the hardware of the chip to handle signals in an out. As a final project we were required to bring this together and hook up:
- a scale running into an amp
- LCD screen
- keypad
And build an acual scale. This is harder than it sounds. Then we needed to build an interface in windows on C, talking to the "scale" over the serial port.

For the other subject we had a motor with I think an rotary positioning sensor. This spoke to a PC over, you guessed it, a serial port. You were required to build a number of differnt control systems to control the rotation of the motor (closed loop, open loop etc). This included working with an interrupt library and a graphics library to generate graphs representing the state of the motor over time.

It was a good degree, and the lecturers really knew their stuff. The place had some pretty strong links to industry, which is generally a good thing in engineering.

Re:Other applications

[Anonymous Coward]

"engineering your system properly"

So... what you're saying is that MankyD and dcam were correct? Accelerometers alone can't do the job. :)

You're rude, you know that? This is just people having a friendly discussion about interesting techs. State the strengths and weaknesses of the argument. Leave witless personal attacks out.

"Wii-lma! Honey, I'm Home!"

[krell]

"I mean, think about it: game controllers with trained pigeons in 'em! That'd take force-feedback to a whole new level!"

You'll need a speaker-hole so that the birds in the controllers could communicate with the miniature pterodactyl inside the console box that actually pulls the strings and sticks to make the game work.

Great Idea

[LordPhantom]

Laser Tag with a doom-style map on the gun/on a wristband?
Brilliant!
Then again, it also makes a great set for a horror movie (big arena, psychopath with a real gun, etc, etc *groan*)

Re:Great Idea

[Anonymous Coward]

You mean like this?

It's true, there's nothing original anymore.

Very odd

[also-rr]

Given the 10+ year development and 20+ year use lifecycles of military equipment it's surprising to see consumer gear _behind_ military tech.

The main reasons for this, of course, are obvious. It's not often that your games console needs the same provable failsafes as a weapon of mass destruction and equally it doesn't cost £10m a unit (launch day eBayed PS3 excepted) so replacing it within a short timeframe isn't going to give you a massive budget deficit.

Re:Very odd

[the.Ceph]

Consumer gear is often behind military tech. Perhaps you have heard of velcro, or GPS, or the internet.

Re:Very odd

[DerekLyons]

Given the 10+ year development and 20+ year use lifecycles of military equipment it's surprising to see consumer gear _behind_ military tech.

It's hard to actually say who is ahead or behind, partly because tech in the real world isn't a linear scale (like it is in various games), partly because the military deploys such a wide variety of accelerometers. The ones used in, say the Trident-II's MK6 guidance, are certainly much larger than these (about the size of a film can) and are 'old style' (asymmetrical floats in fluid) - they are also much more robust and less sensitive to vibration. (The accelerometers in the MK6 Guidance System are also a neat illustration of the nonlinearity of tech in the real world. It uses an advanced form of the same type used in Polaris - because they are more sensitive and accurate than an advanced form of the (quite advanced in and of themselves) ones used in the MK5 guidance of the Trident-I.)

Re:Very odd

[Anonymous Coward]

As you say, it really does depend on what you are talking about. About ten year ago I first started working with an old gravity meter from a Navy sub. They had upgraded to a newer generation. This meter was small (about the size of a large coffee mug). If you moved it from the floor to your desk, the at-rest readings would drop, because it was further from the earth. You can't do stuff like that with these cheap accelerometers.

Re:Very odd

[grammar fascist]

The ones used in, say the Trident-II's MK6 guidance, are certainly much larger than these (about the size of a film can) and are 'old style' (asymmetrical floats in fluid) - they are also much more robust and less sensitive to vibration.

Now that's interesting. Is it the fluid that makes them less sensitive to vibration? (It seems like it would be.) In effect, the fluid would be working as a low-pass filter, so only large movements would be detected.

Does the Wii-mote get around the vibration issue by doing the same thing in software? It seems like a Kalman filter would work more or less perfectly, and those are very simple to implement.

Re:Very odd

[Anonymous Coward]

Velcro does not belong in that list - it was not a military (or NASA) development.

Re:Very odd

[DerekLyons]

The ones used in, say the Trident-II's MK6 guidance, are certainly much larger than these (about the size of a film can) and are 'old style' (asymmetrical floats in fluid) - they are also much more robust and less sensitive to vibration.

Now that's interesting. Is it the fluid that makes them less sensitive to vibration? (It seems like it would be.) In effect, the fluid would be working as a low-pass filter, so only large movements would be detected.

It's partly the fluid, partly the suspension system (the float is partly suspended by it's bouyancy, partly by a magnetic field).
 
 

Does the Wii-mote get around the vibration issue by doing the same thing in software? It seems like a Kalman filter would work more or less perfectly, and those are very simple to implement.

I have no idea how (or even if) the Wii-mote isolates vibration. I'd say they want a certain amount of vibration to filter through - as that could determine if player 'x' hooks instead of slices. Tuneable vibration isolation can also be used to set the difficulty level - less isolation as the level increases.

The "snare" was the first motion-activated weapon?

[xxxJonBoyxxx]

I thought the "snare" was the first motion-activated weapon. Or was it the "covered pit"?

If they come out with a boxing/karate...

[Jawood]

game where I do the moves (gloves and boots that sense when I'm punching and kicking!), I would buy that in a heartbeat! It would be an awesome workout!!!

Think about it. Or have something like Worf's workout from ST:NG! That be sooo cool!

Yeah, I've used those exercise bikes with the screen - it shows you racing with others. It's ok.

Re:If they come out with a boxing/karate...

[anotherone]

The Wii comes with a boxing game, I haven't played it yet though.

Re:If they come out with a boxing/karate...

[painQuin]

The Wii comes with a boxing game, I haven't played it yet though.

It's freaking awesome. I was sweating after three matches. It takes a while to get used to (hey, the tutorial helped when we finally had the patience to follow it) but once you do, no one who is ... well it's not button mashing anymore, air mashing? No one who is air mashing can compete with you. And it's a great workout.

Re:I Thought...

[twistedsymphony]

In all seriousness I believe Nintendo would actually allow it. They really haven't blocked non-family content since the ESRB has been around and people have been able to get a better idea of the game content before they buy it through it's rating. Also have you seen the number of dating sims available for the DS that deal with "touching" not just in Japan but in the US too.

The biggest roadblock to "adult" Wii entertainment isn't Nintendo but retailers, your EBGames, BestBuys, and Walmarts refuse to carry any "AO" rated titles meaning if a company did release them they'd get very limited to almost non-existent exposure... in the US at least (most of the rest of the world is a bit less prudish).

Roll your own

[MarcTheLad]

http://www.freescale.com/files/sensors/doc/data_sh eet/MMA7260Q.pdf

Re:Roll your own

[xlordtyrantx]

Haha, sitting at a Freescale terminal, I clicked on the original link, and got redirected to an internal error page... I've done the same thing posting links from inside of Freescale, don't worry.

MEMS

[Mike1024]

A good picture of a two-axis accelerometer can be seen here: http://users.wpi.edu/~cfurlong/me-593Mech.html (second picture down). Sensing is usually performed by capacitive combs, structures which act as capacitors, with their capacitance varying with displacement.

MEMS accelerometers have dropped in price in recent years because there's a big market: the automotive sector. A typical new car needs two accelerometers, one for the traction control system measuring roughly plus-or-minus 2 to 4g, and one for airbag deployment measuring more like 50g.

Two big manufacturers are Analog Devices and ST Microelectronics, though others exist.

The high demand of the automotive sector has driven prices right down; sensors which would have cost hundreds of dollars in the past can now be purchased in bulk for less than $4. In fact, you could order one right now; component retailers will sell you one for less than $15.

Re:no gadget required to detect the direction of

[heinousjay]

One of these days, your doctor will figure out the dosage and your posting will cease. Truly a sad day for all.

I Can Sense Motion

[eno2001]

Typically it's in my pants while watching Pamela Anderson's sweater meat bounce around like a raver on extacy. Come on! Laugh! It's funny! You KNOW you WANT to.

Re:I Can Sense Motion

[Anonymous Coward]

"Sweater meat"... I haven't heard that one before.
That's a really unappetizing way of describing that part of the anatomy, if you ask me.

Re: You missed the point

[Duggeek]

I know where you can BUMP and NUDGE to affect the gameplay... an actual PINBALL game!!!

It's always irked me to see some hand-held P.O.S. that touts "realistic pinball action". (...action ...action ...ction ...tion)

If I want to play pinball, I'll play pinball.

However, if I want to ride a dragon... well I can't really do that now, can I?

THAT is why the new controllers are so incredible; they give a new, visceral edge to creative gaming... rather than try to "come full circle" with a gaming platform that's already been around- and around- and around again.

I'll grant you that someone will ultimately make a pinball-sized cabinet with two HD screens on it that uses the very implementation you describe. It will be neat, but it won't be real.

You'll get a two-fold "wow factor" out of me when you can manufacture a true-physics pinball game that truly does something no other pinball game has done before. (Remember the face in "Fun House"? Now, that was some awesome innovation, back in its day.)

Oh CNN

[bunions]

Sony Corp.'s "Sixaxis" controller for the PS3 also has an accelerometer. The six axises the name refers to are the three dimensions of space, plus three axises of spin. The company hasn't revealed who makes the chip.

Axises?? How can you mispluralize one of the most entertaining plurals around? Axes, dammit.

Re:Oh CNN

[Anonymous Coward]

Blame Sony - they called their controller SixAxis not SixAxes.

On the plus side, you can pronounce it SexAccess and have people look at you not quite sure if they heard you right.

Re:Oh CNN

[AbRASiON]

Legos

Re:Oh CNN

[Spunkee]

sixaxis is a palindrome. clever.

Re:I Thought...

[kirun]

With T-shirts like this one, Nintendo certainly seem to be moving away from their family-friendly reputation. Yes it's authorised, I read about it in the official mag.

Note: the official mag sucks, buy n-Revolution instead.

oops!

[MarcTheLad]

oops! http://www.freescale.com/webapp/sps/site/prod_summ ary.jsp?code=MMA7260QT There are some app notes below.

Who was first?

[Glacial Wanderer]

The Nintendo Wii Remote one-ups the Sony controller by including an infrared camera.

I think they meant to say: The Sony controller dumbed down the Wii Remote by excluding the infrared camera.

datasheet

[tonigonenstein]

Right from the source: http://www.st.com/stonline/products/literature/ds/ 11115.pdf These things are not exactly new. They are used in the automotive sector, or for "stabilizers" in camcorders.

camera problems

[PhysSurfer]

So what happens if in a game if you point the camera away from the sensor bar? For example, in tennis when you swing the remote I would imagine the camera would lose track of the bar at some point during the swing. How does the system know if you're swinging the racket in the right plane? (Or does it even know?)

Re:camera problems

[anotherone]

It has accelerometers AND the sensor thing. Tennis actually just uses the accelerometers, it works quite well no matter where you're facing.

Re:camera problems

[Anonymous Coward]

The wiiiiiiimote knows where it is going, and if you're pointing at the screen, it knows where it's pointing.

For Tennis, it's not looking for a point, it's looking for a 'swing'. The information from the 'sensor' is broadcast as IR, but the wiimote broadcasts RF only.

Re:camera problems

[PhysSurfer]

Again though, that tells the game if you have the timing of the swing down, not to mention the acceleration and rotation, but what about the accuracy? How does it know whether the racket (Wiimote) was swung in the right plane so that the ball doesn't go above or below it?

Re:camera problems

[DocBoss]

I believe the answer to that is, Magic.

Re:camera problems

[Anonymous Coward]

Conceptually I believe the controller has tilt sensors which could detect this. I'm not sure that wii sports cares though.

Re:camera problems

[Anonymous Coward]

Well, the included tennis game isn't that complex, but the boxing game is- it can pretty accurately reflect where you're holding your hands. I assume it's just using dead reckoning, with only the accelerometers. The hand holding the nunchuck controller is just as accurately modeled as the hand with the remote, suggesting that it's not using the IR sensor (the nunchuck doesn't have an IR sensor).

Can we use this technology with the NES . . .

[abscr]

so I can finally keep Mario from falling down the bottomless pit by jerking the controller above my head?

Re:Can we use this technology with the NES . . .

[Anonymous Coward]

actually they will be selling old games from the NES, SNES, Genesis, and more in the online marketplace for $5-10. So you will get a chance to play mario w/ a wiimote. Though I doubt you can save him lol.

Position sensing

[Jeff1946]

A few years ago I went to a talk on making a position sensor for fire fighters. Remember GPS works poorly inside buildings. The idea was to use microaccelorometers to track the position of the firefighter inside a building. The author mentioned they placed the device in the heel of the boot. This way they could sense when the motion was stopped so they could rezero the accelerometers. Eliminating zero drift has always been a problem with guidance systems.

Question for Slashdot

[xenocide2]

Who decided that things that measure tilt should be called "accelerometers"? They can be used to measure acceleration, but thats not what the sensor directly measures!

Re:Question for Slashdot

[JCondon]

Tilt sensors indirectly measure orientation (tilt). They look at the change in the gravitational acceleration vector with respect to the sensor coordinate frame.

Re:Question for Slashdot

[CityZen]

They're called accelerometers because that's what they measure.

If you hold them still, then they measure acceleration due to gravity. That is, they "point down," thus measuring tilt.

If you wave them about, then it measures the applied force plus acceleration due to gravity. If you know which way is down, then you can subtract out gravity and just measure the applied force. If you don't, well, then, good luck.

Re:Question for Slashdot

[xenocide2]

I guess my big hangup is that an object experiences 1G at rest, and 0G in a freefall.

Re:Question for Slashdot

[Spunkee]

To tilt requires acceleration. They measure acceleration first. Then tilt indirectly.

Re:Question for Slashdot

[Spunkee]

1G is equal to earth's gravitional acceleration. I don't think anything can experience 0G. Everywhere in known space something is causing a gravitational force.

Re:Question for Slashdot

[LKM]

Hm... but if you're falling, you're accelerating at 1G, thus cancelling out gravitation, aren't you?

Re:Question for Slashdot

[fourchannel]

Hm... but if you're falling, you're accelerating at 1G, thus cancelling out gravitation, aren't you?Sort of... When you are in a free fall you are being affected by the Earth's gravity, which in your case is 1G. When you stand on the ground, you are still being affected by 1G, but this time you are fighting that pull with your legs. So you are not cancelling out gravity, a freefall just means you have nothing to counter your 1G acceleration/freefall. Even if you leave the planet, gravitational forces still affect you. The really cool thing is that gravity is instantaneous - meaning that it is not a wave that travels at the speed of light. If you could simply remove the Sun, then all the planets would instantly assume tangent vectors and immediately travel away from the Solar system - it would not take the Earth 8 minutes to break away from the Sun (the time it takes for light to travel that distance) - As soon as the Sun dissaperared, the Earth would immediately change its course.

So when he was saying that nothing can experience 0G, what he meant was...

because gravity is instantaneously tramsmitted, then we are all being affected by the gravitational pull of all objects in the universe. No matter how remote or distant you place something in the deepest, darkest regions of space, it is still being pulled on by gravity from other objects. It's just that the gravitational pull is so small, it is almost 0G, but not exactly 0G.

Motion sensers in furniture

[Mushdot]

"Put me down Steve"

Is it MEMS ?

[Magnusite]

I thought nintendo was supposed to be using the Gyration miniature gyroscopes. Link here

Re:Is it MEMS ?

[Mike1024]

I thought nintendo was supposed to be using the Gyration miniature gyroscopes.

Analog devices make MEMS gyroscopes too. Nintendo could have gone to any vendor, of course.

There's not as much market for gyroscopes as for accelerometers, hence they're more expensive. Sometimes they can be found in car satellite navigation systems as a way of increasing resolution above what GPS can offer - ever heard of a roundabout? They're useful there - and there are other applications as well. Games consoles, for instance!

If you read the article, it says:

Analog Devices Inc. of Norwood, Massachusetts makes a similar chip, which goes into the main Wii controller, the stick-like Wii Remote. According to Analog Devices, ST's chip is used in the auxiliary Freestyle controller (popularly known as the "Nunchuck") that connects to the larger controller for some games. ST said it was not allowed to say where exactly its chip is used.

Sony Corp.'s "Sixaxis" controller for the PS3 also has an accelerometer. The six axises the name refers to are the three dimensions of space, plus three axises of spin. The company hasn't revealed who makes the chip.

Wii Sports - Boxing

[darthservo]

That boxing game is crazy-fun. Think Mike Tyson for NES, but obviously with way better graphics and much more interaction. You use both the Wiimote and Nunchuck (which is how I found it it was also a motion sensor, used to simulate your other hand) to throw literally throw your punches. After three matches, I was starting to work up a sweat. Of course this was after I'd only got four hours of sleep and had been up since 4am waiting in line. Not one who uses my upper body strength on a frequent basis, my arms are a bit stiff today.

No fatigue

[exp(pi*sqrt(163))]

I was worried that something like metal fatigue would set in. But metal fatigue is a result of microscopic fractures in the crystalline structure of the metal. These sensors have moving parts that are fabricated from a single flawless crystal. So nothing like metal fatigue can take place.

There is this one worthy video pinball game

[justthinkit]

I've played the silver ball for 36 years and with one exception I would agree with you. That exception is 3D Ultra Pinball Thrillride -- a video game that plays better than a pinball machine. It is as good as any pinball game in terms of game play, variety and realism. It is better because you never have to clean it or replace worn out components. I picked up a surplused copy for about $10. Much as I love ST:TNG (the show and the pin), a $10 product that never wears out, is fully mute-able and is legally/easily backupable beats it by a mile.

Re:There is this one worthy video pinball game

[Anonymous Coward]

Ultrapin can play real pinball games + there will be games with stuff that you can't do in a real game

MOD THIS GUY UP

[Twisted64]

I don't know what he's saying, but all those big words... they move me.

Re:I Thought...

[triffid_98]

But Sir! That groinal attachment's supposed to have a lifetime guarantee, you've worn it out in nearly three weeks.

I, for one, welcome our new aerobically-inclined SuperMario overlords. The question is this: is Nintendo too family oriented to move into the obvious niche here -- motion sensing interactive pornography?

Guidance system ignorance

[EmbeddedJanitor]

Sure, a guidance system will have accelerometers, but by far the more important part is the gyro. The Wii does not have a gyro. While silicon gyros do exist, they're still relatively large and expensive.

Re:I Thought...

[Mursk]

Goodness! That certainly is risque. I think you can even catch a glimpse of her ankles!

Re:I Thought...

[Meagermanx]

If you were working for Nintendo, do you really think it's a good idea to have pornography branded with your system? It would get all over the news that Ninendo is licensing games sold in adult stores, or selling pornography in their own online shop.
It would be brand-name suicide.

Well, from an european standpoint

[skeldoy]

I think this is another ploy in the american plan to monitor the politically divergant opinions of europeans and other non-americans. :P

Re:New major security hole found in Linux

[Anonymous Coward]

Of course, it is obvious that you are not trying to get people to click the link. Everyone knows what goatse means. What you were trying was to waste mod points. Good job. Too many mod points are used on modding down, it seems.

Futaba makes them...

[Kadin2048]

Not that it's a particularly big market or anything, but MEMS gyros are also used in R/C helicopters as a stabilization/pilot-assist device. They keep the tail of the helicopter pointed in basically the same direction, by adjusting the pitch of the tail rotor dynamically. Without a gyro, the pilot has to constantly make this adjustment in real-time, or risk putting the heli into a spin.

For somewhere around $90-120, you can run out today and get yourself a single-axis "Silicon Micro Machine" gyro that's set up to output a signal to control a standard hobby position servo. The gain on most of them is adjustable, but I assume that you could set it up so that the magnitude of the signal was basically proportional to the deviation from a particular position. Might be a little easier for a hobbyist than going the total DIY route from raw parts.

Re:Futaba makes them...

[Mike1024]

The gain on most of them is adjustable, but I assume that you could set it up so that the magnitude of the signal was basically proportional to the deviation from a particular position.

It's likely they work through PID Control, which stands for proportional, integral, derivative. If this is the case, increasing the gain makes the system respond faster, but can make the system less stable. Wikipedia has a page on the subject.

Re:Futaba makes them...

[Kadin2048]

Fascinating; thanks for the link. As much as I've used servo and feedback networks in hobby applications, I've never really delved into their design very much. It would make a lot of sense if the heli gyros used a control system like that, since they're essentially no different from any other type of industrial-control feedback loop.

Re:I Thought...

[KDR_11k]

I don't think AO would be a problem in Japan, they cut the porn out of the console games because Sony doesn't like porn, not because of the ratings. Though I'm not sure Nintendo would allow the kinds of games that get released for the PC in Japan on the Wii either. Never mind that most of those are just multiple choice text adventures with a few pictures added, I don't think many of those dev teams could write a Wii game that uses the remote if their life depended on it.

Re:I Thought...

[Anonymous Coward]

I dont know if I should laugh or cry

Position sensing with the wiimote

[bVork]

I found this absolutely fascinating video that shows exactly how the sensor bar detects the Wiimote's position - and how you can possibly hack up your own "sensor bar": http://www.youtube.com/watch?v=JTGSkYRDpWY

Thermal accelerometers

[Mixel]

There's another way to avoid damage due to stress. As an alternative, some accelerometers monitor the movement of heated air in a cavity (source). Surprisingly, they can be made MEMS and are cheaper than the mechanical ones (though usually with a factor-of-two loss of accuracy).

wii console, remote and sensor bar

[asjk]

The Nintendo Wii Remote one-ups the Sony controller by including an infrared camera. It picks up signals from a sensor bar the owner attaches to the television set. This enables the remote to "know" where it is in relation to the screen, so the player can use the controller to point to things on the screen -- a useful feature in shooting games (and a lot of games are shooting games).

Here's another interesting piece of information. According to this source, the sensor bar is not even communicating with the console! I guess it's just shooting out a reference point for the remote, to act like a virtual mousepad to the remote's mouse?

Re:I Thought...

[AcidLacedPenguiN]

but even if its just multiple choice text adventures, at least the wiimote can be used like a mouse to select your option.

Re:I Thought...

[thatguywhoiam]

The biggest roadblock to "adult" Wii entertainment isn't Nintendo but retailers, your EBGames, BestBuys, and Walmarts refuse to carry any "AO" rated titles meaning if a company did release them they'd get very limited to almost non-existent exposure... in the US at least (most of the rest of the world is a bit less prudish).

Are you sure that's the roadblock? After all, this stuff is all sold in the same places, and this doesn't seem to affect the other two major platforms...? (Bully does not a trend make?)

Re:I Thought...

[kirun]

Sorry to disappoint you there if you thought I was going to provide a link to hot Nintendo porn. You'll just have to find that yourself.