Microsoft has earned a lot of attention with Natal. It's raised a lot of questions as to how Microsoft can address all the challenges facing their proposed new peripheral. Questions like cost, software, lag in the interface, how to control established genres like FPS and action/adventures.

I'm going to focus on a challenge I haven't seen raised yet: False input. Input into the controller which is entirely unintentional, but interpreted as genuine input by the controller.

Conventional gamepads are very resistant to false input. It pretty much only happens if the controller is dropped or the user makes some kind of error.

Nintendo's wiimote is more susceptible. False input can occur if the user unthinkingly makes a sudden movement, such as scratching an itch, or if there are infrared light sources other than the sensor bar in the room. This can be problematic, as simple sunlight can make a game unplayable, but it can be managed by placing the Wii in windowless room, drawing the curtains, and/or replacing incandescent bulbs with CFLs.

Natal's sensors have a broader scope, and therefore present even more opportunity for false input. What happens if somebody walks in front of the TV while a user is playing? With a conventional gamepad, nothing. With the wiimote, IR control is temporarily cut off, but no false input enters the game. Natal will need a way to distinguish moving objects which are not the user, and discount them as a source of input, or it will try to interpret them as gestures made by the user. How about if a dog or cat rubs up against a player?

Voice command seems like it might be even more problematic. If the word 'pause' is used to pause the game, what happens if the user states in conversation, "I'd like to get my paws on one of those." Will the user have to carefully restrict his/her conversation? A qualifier word might be useful to identify commands, like "Natal, pause." Will Natal be able to reliably distinguish between the user's speech and somebody else's?

Microsoft seems to have bitten off rather a lot. I'll be interested to see how they intend to address all these challenges.

UPDATE

I just saw a clip of Natal on Good Morning America, and I realized another serious problem with false input which I don't think MS will be able to easily overcome: Loose clothing.

In the clip, the show's host is playing Ricochet, and his avatar's pelvis is popping forward and backward alarmingly. The next time the camera cut to the host, I realized the problem: His suit jacket was unbuttoned, and moving loosely around his waist. To Natal, it appeared as though his pelvis was several inches forward from where it actually was.

Loose sleeves and pant legs could seriously compromise the fidelity of Natal control, and I'm not sure if Microsoft will be able to compensate with software. Natal owners will have to get used to wearing tight clothes if they want accurate control, though that isn't really a bad idea if you're going to be playing active games.

All true, though do you really have to change your lightbulbs to get the Wii to work properly???

Anyway, yeah, in that video where there was a family playing the natal with the racing game, the kids were by the side waving their arms about, and I assume it will be quite tough to make sure that that does not muck up the actual driving

Also, Shappert has said that they intend to get their premier franchises on the Natal, but I really don't see how you could get Gears on the Natal. Yeah, you could dive, you could duck behind the couch (well I can't), but would it really be fun, or just really tiring, and the number one question, how would you shoot

In many ways, if you just had the PSMote with the Xbox camera you would get the best of both worlds, because then there would be some input for walking etc or shooting.

My other concern is say you are playing football or tennis. Now in those sports, the key is making proper connection. With tennis, one of the main things that you should do, is watch the ball onto the racquet, and how the hell are you going to know precisely where to put your racquet if the ball does not come out of the screen?

I'm not worrried at all both will fail.

Cool your jets, I've repeatedly corrected people who call Natal an Eyetoy knockoff.

@ Munkeh

Yeah, the IR camera doesn't agree with incandescents. Even if they aren't directly in front of the IR camera, they can reflect off metal objects and confuse it. People should be switching to CFLs anyway. :P

Some of the problems you outline are problems introduced by true 1:1. Developers working on WM+ have already determined that true 1:1 is often detremental to gameplay, so they use WM+ to improve the fidelity of gestures instead. I expect anybody developing for Sony or MS motion controllers will use similar techniques.

I hope so, but still, kicking an imaginary football is going to be tricky, and the point about more accurate controls, say for tennis, is to allow you to use top spin or slice it, so it is up the developers to get the right mix between realism and fun

Ringo's one of the most level-headed posters on the site, I don't think this "observation" really holds here. And he has a good point: false inputs would be an incredible challenge for Natal.

I'm not sure how they would go around handling it, either. Is it possible that they could go for the simplest route by identifying the player's body and voice and then not recognizing inputs from any other source?

@ kowenicki, no that have talked about how they can co-operate, but I don't want my room to be filled with peripherals, like a wall for Gears of War 2

No they are not, and it's a good point, but that doesn't seem to be the direction that Microsoft wants to take with this particular peripheral. I think my solution would work okay, still.

They can, and probably will.

I don't think a standard 360 gamepad with its two-handed grip would work very well with Natal. I do expect that MS will introduce a wand controller similar to the wiimote to help with playing established genres, but this adds to the cost, which could slow adoption.

I agree with Khuutra that Microsoft will want to lock out inputs which aren't from the player, but the question is, will they be able to do so reliably? I think that they can design it so that the camera is rarely confused by false input (it should be able to see false objects coming and ignore them, unless they get so close that it looks like a single object to the camera), but I'm not so convinced that the voice recognition will be able to filter out a conversation on the couch behind you.