The researchers from Georgia Tech have logged every key a subject typed on his PC by using a smartphone accelerometer – the internal device that detects when and how the phone is tilted – to sense keyboard
vibrations and decipher complete sentences with up to 80 per cent accuracy. The procedure is not easy, they say, but is definitely possible with the latest generations of smartphones.
The technique works through probability and by detecting pairs of keystrokes, rather than individual keys.
It models “keyboard events” in pairs, then determines whether the pair of keys pressed is on the left versus right side of the keyboard, and whether they are close together or far apart. After the system has determined this for each pair of keys depressed, it compares the results with a dictionary. The technique only works reliably on words with more than three letters with an accuracy as high as 80 per cent.