Thats very cool... i heard of someone implementing that with a nord-modular....
If you browse the forums maybe you can find it... Its a cool thing to have for Sound-Installations... Best Luigi Am 07.08.2008 um 21:16 schrieb Ico Doornekamp: > > Hi all, > > Yesterday I found out that modern audio cards can do much higher > sample > rates then 48000, which allows for entertaining experiments with > ultrasound. > > I'm not sure if this has been done before, but I'm pretty happy > with the > results so far. > > I've created a patch running on a samplerate of 88200 Hz, which sends > out high-frequency chirps over two laptop speakers. The chirps are > reflected back to the bultin mic using both hands. The reflection is > correlated with the outgoing chirps to calculate the time the sound > waves needed to return to the mic, thus measuring the distance to the > hands or any objects hovering above the laptop. > > This particular patch just drives two tone generators whose > frequencies > depend on the measured distances, which are played back over the same > speakers as the high-frequency chirps. The result is a > two-tone-polyphonic theremin-like instrument. > > If only I could play this thing in tune... > > A simple demonstration video and the patch can be found at > > http://zevv.nl/play/code/ultrasonic-theremin/ > > This patch just a first test using ultrasound, I'm sure much more > interesting things can be done using this technique. > > The patch is not very well documented at this time, and I think > getting > things to work needs a fair amount of tweaking for each different > setup. > Things that need to be setup properly are output level of the > soundcard, > a magic gain factor after the correlation, and the range that > should be > inspected for echo peaks to avoid detecing of reflections from the > ceiling. I think it would be possible to make the patch do some > auto-detection of some of the paremeters like ceiling height and gain > factors, which would make a nice addition for future versions. > > Enjoy, > > Ico > > -- > :wq > ^X^Cy^K^X^C^C^C^C > > _______________________________________________ > Pd-list@iem.at mailing list > UNSUBSCRIBE and account-management -> http://lists.puredata.info/ > listinfo/pd-list > _______________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list