It's common for us to address our computers using hand gestures, although many convey frustration and may involve a single finger. In the future, however, sign language could become an effective way of surfing the Web, managing files or manipulating virtual objects on screen.

Microsoft Research is developing a project called SoundWave that's like an Xbox Kinect for PCs. However, instead of using a special camera to record and interpret motion, SoundWave relies on your computer's speakers and microphone. The speakers emit an inaudible tone. The microphone senses these audio waves as well as any change in their frequency when they reflect off a moving object such as a hand.

Software then uses the Doppler effect to calculate the speed, direction and amplitude of this motion and interpret its meaning. For example, a wave of the hand lets you scroll through pictures or song. Using a seesaw motion with both hands lets you rotate images onscreen.

Microsoft still has some kinks to work out, but SoundWave could have us someday saluting our computers, not to mention tablets and smart phones, with all five fingers.

—Larry Greenemeier

[The above text is a transcript of this podcast.]