Leg action
Exploring alternative ways we can interact with our mobile devices is the work of the Gesture-based Interaction research team, part of the Interaction and Graphics Group at Bristol University. They are finding ‘footie’ to be an effective navigation tool, with kicking gestures being used for ‘hands-free’ communication.

Finding a way to detect gestures, led the team to the Kinect for Microsoft Xbox camera system. A big component of their work was producing the algorithms to register that a leg had moved in a particular way. The team believes that motion-sensing cameras will become standard in mobile phones.

How gestures work
Dr Jason Alexander, now teaching at the University of Lancaster, and part of the team, describes their approach: ‘once we established that you could interact using your leg, we produced a lot of algorithms to detect how far forward, how fast, and what angle from a straightforward position you had moved your leg. Then we translated these into gestures we could use for interactions.’

Their first significant insight, Alexander continues, ‘was that people can regularly and accurately kick in five different directions and at 180o in front of them. So if you are creating a menu, you shouldn’t put more than five items in that menu, otherwise people will struggle to select the correct item.’ Their second finding was whether people could vary the velocity of their kick to scroll around a screen. Their results showed two options. People weren’t very good at kicking at different speeds, but could kick accurately either slowly or fast.

Refining kick commands
The next step is integrating the programming for interpreting the gestures into a mobile device, testing it and putting it out in the real world. For now, they are busy refining the gestural commands. Alexander asks, ‘if you were kicking forward would people expect their screen to move forward or backward?’ Questions like this need to be explored.  

The team believe that most of the functions on a mobile phone could be mapped to a kick gesture if we wish them to be. So when our hands are full, kicking our favourite tunes to play on our mobiles could be our default selection.