iOS App Acoustically Measures Distances Up To 25 Meters

Posted by samzenpus on Sunday November 13, 2011 @08:07AM from the new-tool-for-the-box dept.

n01 writes "A recently published app for the iOS platform uses the propagation of sound waves to measure distances of up to 25 meters in a dual device mode. The technique works through repeatedly sending a chirp signal from the master device to which the other (reflector) device synchronizes itself and then replies in a similar fashion. A novel combination of techniques has been engineered to enhance the robustness in noisy environments, such as using an optimum-autocorrelation-signal and semi-automatic frequency calibration together with an averaging over multiple cycles."

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XO (OLPC) by itamblyn · 2011-11-13 08:12 · Score: 5, Informative

http://wiki.laptop.org/go/Distance
Re:wait, dual-device mode? by n01 · 2011-11-13 10:01 · Score: 5, Informative

You can also use the device in a single device mode (with headphones), as shown in the second video. I just thought that the dual device mode would be more interesting and therefore emphasized it in my submission.