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Tiny gyroscopes

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MintJulep

MintJulep

Mechanical
Jun 12, 2003
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One of the questions I ask when interviewing engineers is about how the Nintendo Wii controller detects motion.

Looks like I'm going to have to change my acceptable answer.

The latest version of the controller includes tiny MEMS gyroscopes.

 
OK, I'll ask the dumb question, these are actually very small mechanical gyros right?

I clicked on a couple of the links and had trouble confirming.

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Not gyros in the greek sense (gyro meaning rotating). More coriolis based with vibrating reeds that precess when turned.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
How'd they do it before (my granddaughter asked me that last Christmas and even at 7 years old, she wasn't accepting "magic" as a valid answer)?

David
 
Was there any 'before'? The Wii is something I can't remember seeing before Wii.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
Just accelerometers and the sensor bar.

That said this isn't brand new, I think the link Mint gives is dated 2008, certainly when we got our son one in 2009 the motion plus accessory which contains the gyro was already available.

So Skogs, a dullard like me could think of them almost like a spoked wheel and you actually measure the deflection/strain of the 'spokes', or something like that?

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MintJulep said he was going to have to change his stock answer. I was just wondering from what to gyros.

David
 
I noticed the new remotes (fine--"Wiimotes") are "new". They've got the twist/rotation sensors built in now, so you don't need the $20 add-on clicked into the base to play Tiger Woods Golf (or whatever you like) if you have a new remote ("Wiimote", dammit).

So--they've done something recently that involves such changes, whatever's actually happening inside. Faster, better, cheaper, eh?



Jeff Mowry
A people governed by fear cannot value freedom.
 
That article mentions the "motion plus" thingy that attaches to the bottom of the remotes ("Wii-friggin-motes"), and games like Sports Resort use them to detect slices or hooks in golf, for instance.

The new remotes (nevermind) have the add-on "motion plus" thing built into them, in the same space the old remotes used without the add-on parts. Nifty, and less expensive than the two parts, but a bit more than the old remotes alone.



Jeff Mowry
A people governed by fear cannot value freedom.
 
If memory serves, some games wouldn't work properly with the older motion plus sensor installed (or maybe my kid was full of it).

Presumably they've found a way around this issue with the new integrated remotes.

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That could well be. We had to get the add-on bits when we got the Sports Resort game, and it came with an extended silicone sleeve to fit over everything. Bulky! Took some getting used to.

Perhaps some of the non-Wii-branded games have some difficulty with the hardware?



Jeff Mowry
A people governed by fear cannot value freedom.
 
The acceptable answer before was accelerometers, with the acceleration data integrated to obtain velocity.

The question is intended to gage if the candidate has any understanding of Newton's laws of motion, if they were paying any attention in Calculus.
 
Yes, Kenat. That is how I have understood it. Only, the spokes do not rotate, they just vibrate and when moved perpendicular to vibration, they excert a force perpendicular to that motion. Just like a gyroscope precesses in the 'third direction/axis'.

Not sure how that force is picked up. There are several possibilities that can be used in MEMS.

Mind you, I haven't opened one. But been to a MEMS seminar where the design was discussed. It may well be that the seminar guys were just guessing. But it makes some sense to me.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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