When touchscreens came to the first iPhone, they felt like a marvellous new way to interact with the devices in our hands. Dirty or wet or gloved fingers reveal the limitations of the touchscreen though, and touchless interfaces may be closer than you think -- a lightly modified ordinary phone can detect hand gestures through interference of radio waves.
Researchers at the University of Washington look a regular touchscreen phone and attached a circuit board with four small loop antennae. It's bulkier than a sleek naked phone, for sure, but not much worse than some monstrosities that pass for phone cases. These antennae detect interference in the radio waves that phones uses to communicate with cell towers.
"When the user moves their hand around the mobile phone," write the authors, "their skin, muscle, and bones affect the character of the propagation path by absorbing or reflecting part of the signal." By analysing how each of the four antennae receive the signal, the phone can distinguish between taps in eight locations, four hover gestures, and swipes in two directions.
With an average accuracy of 87 per cent, it's still clunkier than we've come to expect from our phones. But this is pretty preliminary research that will be presented at a user interface conference next month. It's fascinating that tinkering with even relatively low-tech components can create a whole interface. [via New Scientist]
Pictures: Zhao et al