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How the Wiimote Works

Posted by ryuzaki0 on from the little-tiny-marios dept.

The New York Times' 'How it Works' series touches on a remote with a twist: the Nintendo Wiimote. The article describes the micron-sized machines that make it work, displays cut-away graphics of the little white marvel, and rounds out the discussion with a breakdown of where the tech came from. From the article: "The controller's most-talked-about feature is the capacity to track its own relative motion. This enables players to do things like steer a car by twisting the remote in the air or moving a game character by tilting the remote down or up. 'This represents a fabulous example of the consumerization of MEMS,' the tiny devices known as micro-electro-mechanical systems, said Benedetto Vigna, general manager of the MEMS unit at STMicroelectronics, a leading maker of the accelerometers embedded in the controllers. (Nintendo itself declined to talk about the controllers' inner workings.) He said the motion sensors, using the technology that activates vehicle air bags, can accurately sense three axes of acceleration: up and down, left to right, and forward and backward."

7 of 135 comments (clear)

  1. Re:Wait... by jizziknight · · Score: 2, Informative

    Rotation, however, does not denote an axis. Conventionally, in spatial geometry/physics, an axis represents a dimension.

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  2. Didn't Live Up To The Hype by Anonymous Coward · · Score: 2, Informative

    After having used my Wii and the controller for a couple weeks now I've been somewhat disappointed with the technology.

    First, the Wiimote isn't an absolute pointing device. It's all relative to the Wiimote bar you place near your TV. Everything is relative to that device, so you are never actually pointing accurately at anything on your screen.

    Second, the Wiimote has accuracy/responsiveness issues. Not sure if it is interference from bright lights or some other type of wireless/electronic devices. There are times where you are having to repeat the same motions over again because the Wiimote isn't registering.

    Nothing fatal, but the hype certainly has worn off. Hopefully Nintendo will be coming out with updates to make the Wiimote more consistent in registering input over the next year.

    1. Re:Didn't Live Up To The Hype by Daemonstar · · Score: 4, Informative
      It's all relative to the Wiimote bar you place near your TV. Everything is relative to that device, so you are never actually pointing accurately at anything on your screen.
      That's because the bar provides the infared source so the Wiimote has a frame of reference for the TV screen. Since it provides the infared source, anything that may alter the source will interfere with the Wiimote (i.e.: shiny surfaces like a coffee table, glass, mirrors, etc.). Of course, it is also why you can substitute the bar for 2 candles.
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    2. Re:Didn't Live Up To The Hype by nuggz · · Score: 4, Informative

      If your wiimote is a little off make sure you check the sensitivity to calibrate it.
      I found that made a huge difference.

    3. Re:Didn't Live Up To The Hype by El+Gigante+de+Justic · · Score: 5, Informative

      First, the Wiimote isn't an absolute pointing device. It's all relative to the Wiimote bar you place near your TV. Everything is relative to that device, so you are never actually pointing accurately at anything on your screen.

      I don't think it ever was lauded or presented as an absolute pointing device prior to its release, but it is a very good ubiquitous pointing device and not simply a one trick pony as something like the Zapper was. As stated by others before me, this is because the sensor bar emits the IR which the wii-mote triangulates its pointing position from. It definately works best on the top of the TV, IMO. Ideal setup can vary depending upon whether you are typically sitting or standing, how high your TV is relative to the ground/seat, etc. Calibrating it is important too -- in my mind, that's one of the things that killed Red Steel - you can only calibrate at the very begining of the first level and not from the pause menu while pointing is an essential part of the controls. In Zelda:TP, you can play entirely without using the pointer and it still has a more advanced calibration option than the beginning of Red Steel available at all times (if only you could turn down the tingling fairy sound).
            It would not be possible to have an absolute pointer that would work on all TVs; they would have to actually sell a Wii TV (a Wii-V?) with the IR beams behind the screen to make an absolute pointer. The reason the Zapper and other light guns worked as something like an absolute pointer is because the tech was different, and as I understand it will not work on some modern TVs (I can't recall if its LCD or Plasma). When you pulled the trigger on the Zapper, the screen flashed black for a frame, and the area around the target sprites flashed white after that to indicate a target. The photo-receptors in the Zapper would detect that different to determine a hit or miss. Would you really want the screen flashing right with every shot in any modern FPS? The problem with using something like an invisible later pointer is that TV screens are not flat, and are usually convex. To do a reflective pointer you would ideally want a concave screen with the player at the focal point. By using IR and having each Wii-mote figure out its own position, you don't have to worry about different controllers interfering with each other's signals, etc.

      Second, the Wiimote has accuracy/responsiveness issues. Not sure if it is interference from bright lights or some other type of wireless/electronic devices. There are times where you are having to repeat the same motions over again because the Wiimote isn't registering.

      If you're having accuracy/responsiveness issues with the pointer, your most likely culprits are 1) other bright lights (including sunlight) in your gaming area 2) Other heat sources that aren't lights in the gaming area (i.e. laptop with running harddrive on the coffee table) 3) possibly reflective surfaces, but doubtful. If you aim your Wii-mote away from the screen and happen to pass another heat source like a candle or laptop, it may temporarily focus on that for triangulation, causing all sorts of problems, so keep your gaming area free of IR sources that can distract the remote. Lights should only be a problem if they are also a significant heat source (incandescent bulbs), and darkened rooms are better for gaming anyway.
            I haven't had any obvious problems with Wi-Fi, but it and Bluetooth do operate in the same range, as do most cordless phones. If you're having response problems regularly, try changing the set channels on your Wireless router and/or cordless phones.
            As for response issues with other motions, I have occasionally noticed some problems (like with batting in Wii baseball), where the bat seems way off, but if you go back to a base position and restart your motions, it usually comes out just fine. One of the tricky parts to motion recognition is determining which motions were deliberate and which are casual motions not meant to take an action. I much more often accidentally do something with a casual motion than have actions go undetected.

  3. The one missing feature by J-1000 · · Score: 2, Informative

    While I love the Wiimote and Nunchuk, I think they really suffer from the lack of at least a single-axis gyroscope. The accelerometer is great for measuring tilts in relation to the earth's surface, but they can't register angles on axes perpendicular to the earth's surface. This makes it more difficult to register a camera pan to the left or right, for instance, without involving the IR sensor.

    The most obvious use (to me) for such a feature would be to have the Nunchuk pan the camera left and right as you point it left and right (in FPS games for instance), but it would also improve situations like batting and swordfighting where you want the instrument onscreen to match the angle of the Wiimote as closely as possible.

  4. Re:Motion or angle? by HappySqurriel · · Score: 2, Informative

    I'm a bit confused. The ability of the Wiimote to sense the angle it's at seems quite consistent, and doesn't appear to be possible to "fool", while the ability to sense motion can be fooled somewhat.

    There is a reason for that ...

    The Force of Gravity will always register as an (aproximately) 9.81 M/(s^2) acceleration to the acclerometers inside of the Wiimote; this means that you should be able to tell it's orientation in comparison to the ground pretty easily.

    I'm a bit confused. The ability of the Wiimote to sense the angle it's at seems quite consistent, and doesn't appear to be possible to "fool", while the ability to sense motion can be fooled somewhat.

    Personally, I'm not sure what you mean by "fool" the ability to sense motion though ... For the most part, the Wii accepts a wide variety of input largely because the games have to be useable with small motions for a 3 foot tall child / little person and also usable with large motions for a 7 Foot tall adult. If Tiger Woods Golf (as an example) had a swing clinic to test your real golf swing, I doubt it would be easy to trick it with a wrist flick.