Motion Controls And You. Part 1: waggle!

Motion Controls And You. Part 2: MotionPlus and the myth of "1:1"

Motion Controls And You. Part 1: Waggle


    This is a series of posts that investigate in the field of motion controlled gaming. Beginning with the Nintendo Wii Remote that was announced in 2005, the goal is to look at each of the following systems - MotionPlus, Natal and Arc - looking into their respective technologies, advantages, disadvantages and implementations. (Or nobody cares and this will quickly disappear again.)
 
 
    Nintendo was never very technical when unveiling and demonstrating new hardware and, much like Wii Sports did in 2006 with the capabilities of the Wii Remote, Wii Sports Resort has a habit of making people believe MotionPlus is capable of doing much more than it actually does.

    It is not very surprising, then, that some early importers of Zangeki no Reginleiv and some hands-on reports of Red Steel 2 express careful scepticism: "Yeah, its very cool and all, but why isn't it 1:1?"

    Nintendo lets this happen, and is setting a lot of people up for disappointment over upcoming releases, most notably The Legend of Zelda, by resorting to a simple and effective "Wii Motion Plus will transfer your movement into the game more precise than ever before!" instead of actually telling them what they can and more importantly, what they cannot expect. So lets get technical.


 First, let's look at what is inside the regular Wii Remote that made it necessary to release this add-on in the first place.

    Apart from all the usual stuff for buttons, sound and vibration, the distinct features of a Wiimote are an Infrared Camera at the top, and a three-axis ADXL330 accelerometer right next to the A-Button (to the right of the red tube in the picture above). This tiny bug-sized little chip is where all the waggly magic happens. With a price tag of $25 per chip, you may see why the Wii remote, containing the ADXL330, a bluetooth radio and a multi-point 1024x768 100hz infrared camera is considered a remarkably cheap and diverse piece of hardware amongst hackers and homebrewers.

    The bluetooth Infrared camera inside the Wiimote picks up two flickering spheres of infrared light (IR cameras see IR light and nothing else) coming from the sensor bar. Because these spheres change position and distance depending on where you hold the Wiimote, this data is used for your cursor (that is why it isn't perfectly mapped to where you point - the Wii doesn't know where and how big your TV is, only where the sensor bar is), both for its position and for its distance from the sensor bar.
 Good in theory.


    What the ADXL330 accelerometer does is to detect relational acceleration along three axis - it measures the g-force that acts upon it. During acceleration, it can measure and record the XYZ direction, duration and speed it is moving in and sends this data via bluetooth to the Wii. When it is hold still, it is able to deduce its orientation in 3D space because of the downwards gravitational pull - until you turn it over. Turning it over along one of the axis provides ambiguous data, and the reading becomes unstable or useless. The same goes for unexpected change of orientation during accelerated movement: Straight lines of movement are awesome, wavy lines or rotation not so much.

    Can you see where this is going? Cursor functionality aside, the Wiimote can detect its orientation in space, as long as it is hold still, and even then there is a high probability of error, especially when you turn it over. The probability of error when detecting accelerated motion is even higher, even more or less straight lines of motion cannot always be measured correctly.

And this is the technology Nintendo went with for detecting and translating motions of the human arm!

 
 This is you.
     Three years later, the number of Wii games that employ this technology for great effect, circumventing the shortcomings, creating situations where gamers won't use the remote in ways that confuse the accelerometer is slim, though there are some. Games like Wii Sports, that feel like they know a lot of what you're going, when in fact they're based on "is there quick motion and if so, when did it end?"; games like Zack&Wiki that change things up a lot and are very careful about crafting situations in which the player naturally does the "right" motions, games like The Force Unleashed that, while not perfect, use rotation and quick thrusts for so many nice moves that you cannot help but have fun - or games like MadWorld that create situations where the motion input might not be very elaborate, but are so well staged, paced and forgiving that they are directly translated into a big, mad grin on your face. In Dead Space: Extraction, you solder bolts, handle the ripper, melee enemies and do active reloads by pointer, distance AND gesture input, enhanced by the Wiimote speaker and rumble. Those are the moments when the technology really shines.
 Zack & Wiki - One of the games that sport excellent Motion Controls

    After the unsuccessful and saddening attempts at elaborate gesture-controlled segments of the first few waves of games however, games that turned many people away from the console, the majority of devs settled on simply using an I/O system - substituting a button press for "accelerator sending any sort of motion data". This (in many cases) pointless shaking of the Wiimote became quickly known as "waggle", and is very enthusiastically used to this day, even though it is mostly avoided or rather cleverly used these days.

    Code seems to have improved on the reading of "jabs", the "distance" reading of the pointer is seen increasing popularity, unreliable gesture input is avoided and waggle only sparsely used in high-profile games - combining motions with the Nunchuck has also proven to work quite well. Interestingly, there is not an ADXL330 in the Nunchuk, but a "LIS3L02A", also a three-acis accelerometer that costs roughly the same but consumes less power. I have read one forum post that it actually works slightly better than the one used in the Wiimote itself, and that techies actually buy Nintendo Nunchucks as a cheap way to get a hold of LIS3L02As. Maybe the only reasons these are not built into the 'mote is cost reduction? Who knows.

    But the inconsistencies and the very, very small room of possible implementations of the Wiimote and Nunchuck accelerometer remain, and the Classic Controller is getting more popular every week - especially in Japan. So popular that even games predestined for motion input such as No More Heroes 2 and Zangeki No Reginleiv receive optional Classic Controller support. And those in favor of regular Wiimote gesture input are often so because they have found out how the system wor ks, controlling their motions, knowing what the controller can do and what it can't do. Quite the opposite of the intuitive, easiliy approachable motion controls big N might have had in mind.

    And that is even though Nintendo released a little peripheral in the summer of 2009 - over seven months ago - called MotionPlus, that, according to Nintendo themselves, contains technology that "was initially planned for the original hardware, and should have been in there from the start."


 


Next up: 

Wii Motion Plus - Dispelling the myth of "1:1"

16 Comments
17 Comments
Edited by Meowayne
Motion Controls And You. Part 2: MotionPlus and the myth of "1:1"

Motion Controls And You. Part 1: Waggle


    This is a series of posts that investigate in the field of motion controlled gaming. Beginning with the Nintendo Wii Remote that was announced in 2005, the goal is to look at each of the following systems - MotionPlus, Natal and Arc - looking into their respective technologies, advantages, disadvantages and implementations. (Or nobody cares and this will quickly disappear again.)
 
 
    Nintendo was never very technical when unveiling and demonstrating new hardware and, much like Wii Sports did in 2006 with the capabilities of the Wii Remote, Wii Sports Resort has a habit of making people believe MotionPlus is capable of doing much more than it actually does.

    It is not very surprising, then, that some early importers of Zangeki no Reginleiv and some hands-on reports of Red Steel 2 express careful scepticism: "Yeah, its very cool and all, but why isn't it 1:1?"

    Nintendo lets this happen, and is setting a lot of people up for disappointment over upcoming releases, most notably The Legend of Zelda, by resorting to a simple and effective "Wii Motion Plus will transfer your movement into the game more precise than ever before!" instead of actually telling them what they can and more importantly, what they cannot expect. So lets get technical.


 First, let's look at what is inside the regular Wii Remote that made it necessary to release this add-on in the first place.

    Apart from all the usual stuff for buttons, sound and vibration, the distinct features of a Wiimote are an Infrared Camera at the top, and a three-axis ADXL330 accelerometer right next to the A-Button (to the right of the red tube in the picture above). This tiny bug-sized little chip is where all the waggly magic happens. With a price tag of $25 per chip, you may see why the Wii remote, containing the ADXL330, a bluetooth radio and a multi-point 1024x768 100hz infrared camera is considered a remarkably cheap and diverse piece of hardware amongst hackers and homebrewers.

    The bluetooth Infrared camera inside the Wiimote picks up two flickering spheres of infrared light (IR cameras see IR light and nothing else) coming from the sensor bar. Because these spheres change position and distance depending on where you hold the Wiimote, this data is used for your cursor (that is why it isn't perfectly mapped to where you point - the Wii doesn't know where and how big your TV is, only where the sensor bar is), both for its position and for its distance from the sensor bar.
 Good in theory.


    What the ADXL330 accelerometer does is to detect relational acceleration along three axis - it measures the g-force that acts upon it. During acceleration, it can measure and record the XYZ direction, duration and speed it is moving in and sends this data via bluetooth to the Wii. When it is hold still, it is able to deduce its orientation in 3D space because of the downwards gravitational pull - until you turn it over. Turning it over along one of the axis provides ambiguous data, and the reading becomes unstable or useless. The same goes for unexpected change of orientation during accelerated movement: Straight lines of movement are awesome, wavy lines or rotation not so much.

    Can you see where this is going? Cursor functionality aside, the Wiimote can detect its orientation in space, as long as it is hold still, and even then there is a high probability of error, especially when you turn it over. The probability of error when detecting accelerated motion is even higher, even more or less straight lines of motion cannot always be measured correctly.

And this is the technology Nintendo went with for detecting and translating motions of the human arm!

 
 This is you.
     Three years later, the number of Wii games that employ this technology for great effect, circumventing the shortcomings, creating situations where gamers won't use the remote in ways that confuse the accelerometer is slim, though there are some. Games like Wii Sports, that feel like they know a lot of what you're going, when in fact they're based on "is there quick motion and if so, when did it end?"; games like Zack&Wiki that change things up a lot and are very careful about crafting situations in which the player naturally does the "right" motions, games like The Force Unleashed that, while not perfect, use rotation and quick thrusts for so many nice moves that you cannot help but have fun - or games like MadWorld that create situations where the motion input might not be very elaborate, but are so well staged, paced and forgiving that they are directly translated into a big, mad grin on your face. In Dead Space: Extraction, you solder bolts, handle the ripper, melee enemies and do active reloads by pointer, distance AND gesture input, enhanced by the Wiimote speaker and rumble. Those are the moments when the technology really shines.
 Zack & Wiki - One of the games that sport excellent Motion Controls

    After the unsuccessful and saddening attempts at elaborate gesture-controlled segments of the first few waves of games however, games that turned many people away from the console, the majority of devs settled on simply using an I/O system - substituting a button press for "accelerator sending any sort of motion data". This (in many cases) pointless shaking of the Wiimote became quickly known as "waggle", and is very enthusiastically used to this day, even though it is mostly avoided or rather cleverly used these days.

    Code seems to have improved on the reading of "jabs", the "distance" reading of the pointer is seen increasing popularity, unreliable gesture input is avoided and waggle only sparsely used in high-profile games - combining motions with the Nunchuck has also proven to work quite well. Interestingly, there is not an ADXL330 in the Nunchuk, but a "LIS3L02A", also a three-acis accelerometer that costs roughly the same but consumes less power. I have read one forum post that it actually works slightly better than the one used in the Wiimote itself, and that techies actually buy Nintendo Nunchucks as a cheap way to get a hold of LIS3L02As. Maybe the only reasons these are not built into the 'mote is cost reduction? Who knows.

    But the inconsistencies and the very, very small room of possible implementations of the Wiimote and Nunchuck accelerometer remain, and the Classic Controller is getting more popular every week - especially in Japan. So popular that even games predestined for motion input such as No More Heroes 2 and Zangeki No Reginleiv receive optional Classic Controller support. And those in favor of regular Wiimote gesture input are often so because they have found out how the system wor ks, controlling their motions, knowing what the controller can do and what it can't do. Quite the opposite of the intuitive, easiliy approachable motion controls big N might have had in mind.

    And that is even though Nintendo released a little peripheral in the summer of 2009 - over seven months ago - called MotionPlus, that, according to Nintendo themselves, contains technology that "was initially planned for the original hardware, and should have been in there from the start."


 


Next up: 

Wii Motion Plus - Dispelling the myth of "1:1"

Posted by Willy105

This is great.

Posted by Rallier

I really wonder how Zangeki no Reginliev works with the classic controller since tilting the wii remote and nunchuck are essential for some of the weapons. 
 
The Wii-remote solo did indeed do a poor job as soon as the motions became somewhat elaborate. It was SSX Blur with the uber-moves that made that clear for me, once i realised to hold the wii-remote "flat" I had no problem pulling those moves off though. It was the same for Dragon Quest Swords. My would it be amazing if that game gets a M+ sequel.

Posted by Meowayne
@Rallier: Wait, do you have Reginleiv?
Posted by c1337us

Great post.

Posted by Rallier
@Meowayne: Yep, Im about 17hours in. That game is way longer than i thought it would be (and that i makes itself appear amusingly enough).
Edited by Meowayne

Heh. During my research for the second part and reading press releases of motion control device manufacturers, I think I have stumbled upon the technology used in Sony's Arc, even though it hasn't been officially specified yet. Nice. :D
 
Edit:
 
This video illustrates the shortcomings of accelerometers quite nicely.
 

Posted by Teptom

This was a interesting read. Looking forward to Part 2.

Posted by Cornman89

This is brilliant. Good show.

Posted by Meowayne

Thank you all. :)
 
The next one is going to be a bit longer, I'm afraid.

Posted by Geno
@Meowayne: Good blog, but how can you comment on the technologies of Natal and Arc if they're not even out yet? 
Posted by Meowayne

You'll see. :)

Posted by iam3green

this is a very great blog :)

Posted by demontium
@Meowayne: More amazing blogging that most people won't read because of its length.
Posted by Meowayne

I must admit I am one of those that don't usually read very long blogs. :D
 
But its fun so. Durr.

Posted by Cook66

You guys either need seperate avatars or you need to keep to seperate threads. :P
Anyway. Great blog, I'm looking forward to the next one. :D

Posted by Cerza

Excellent blog! I look forward to reading part 2.