Linked by Thom Holwerda on Tue 10th Jul 2012 01:24 UTC
Microsoft "Microsoft and Perceptive Pixel Inc. (PPI) today announced that they have entered into a definitive agreement under which Microsoft will acquire PPI, a recognized leader in research, development and production of large-scale, multi-touch display solutions." Yes, Jeff Han is now a Microsoft employee. This demo still amazes me - from 2006. Before the iPhone. Before Android. Before the iPad. Remember that the next time you wind up in a discussion about who supposedly invented what.
Thread beginning with comment 526209
To view parent comment, click here.
To read all comments associated with this story, please click here.
RE[3]: I built one too!
by Alfman on Tue 10th Jul 2012 14:26 UTC in reply to "RE[2]: I built one too!"
Alfman
Member since:
2011-01-28

Just to entertain the idea and play devil's advocate here:

If the system relies on the speed of sound reaching sensors, I suspect that's usually fairly constant in most environments. I'd expect the air density to be consistent across the surface, windspeeds of 15+ MPH (sorry, Km/H) would be unusual and that's still only about 1% error against the speed of sound.

Tuning the sensors to a specific frequency should be trivial, and one could even implement frequency hopping and/or multi-spectral tones which are unlikely to be duplicated in any natural environment.

Whether it is superior or not to capacitive touchscreens somewhat misses the point that it may be "good enough" and far more affordable. It could work on natural surfaces too, like walls and floors.


Edit:
Thinking about it further, it should be possible to compensate for the wind-speed issues as well by pairing up the microphones with speakers and detecting the sound waves from the other microphones. This could additionally help automatic calibration and maybe even adhoc placement of the microphones on arbitrary surfaces without any frame at all.

With an appropriate sensor array, I think an acoustic system might be made to work in 3 dimensions. Capacitive sensors can't really do that.

Edited 2012-07-10 14:38 UTC

Reply Parent Score: 3

RE[4]: I built one too!
by zima on Tue 10th Jul 2012 15:55 in reply to "RE[3]: I built one too!"
zima Member since:
2005-07-06

windspeeds of 15+ MPH (sorry, Km/H) would be unusual

Kelvin-meter per Henry? That does seem like an unusual wind ;)

Reply Parent Score: 2

RE[4]: I built one too!
by Laurence on Wed 11th Jul 2012 09:42 in reply to "RE[3]: I built one too!"
Laurence Member since:
2007-03-26

I think you've missed my point because wind speed should never need to come into the equation unless you're using the general purpose front mic (which, quite frankly, is a silly idea).

Reply Parent Score: 2

RE[5]: I built one too!
by Alfman on Wed 11th Jul 2012 14:51 in reply to "RE[4]: I built one too!"
Alfman Member since:
2011-01-28

Laurence,

"I think you've missed my point because wind speed should never need to come into the equation unless you're using the general purpose front mic (which, quite frankly, is a silly idea)."

Firstly, if the mic picks up the frequencies you need, then it's not silly at all. If it doesn't, then you'll need something more specialised, but as a hobby project it makes plenty of sense to start out with off the shelf equipment when possible.


Secondly, any acoustic system will necessarily be affected by windspeed regardless of the equipment you use. I think you may have misunderstood me, I'm not talking about noises caused by wind, I'm talking about the physics of audio propagation and how wind will offset the triangulation of a ping from it's true origin.

Therefore, IF wind is anticipated (ie outdoors), then it must be compensated or it will affect the accuracy of the system.

Edit:

Neolander is talking about detecting taps on against a board, but I'm talking about tracking a stylus in 2d/3d space using emitors and microphones. It could scale to large natural areas like the football example, or maybe even in swimming pools.

Of course, it makes more sense to use radio instead, but the discussion was about DIY projects, where audio is easy to do.

Edited 2012-07-11 15:08 UTC

Reply Parent Score: 2