Touch My Phone

While primarily aimed at app developers, this article also gives laypeople a good idea of how their phones interpret their swipes and taps, introducing concepts such as centroids and contact patches.  Accommodating the irregularities of the human hand (and user idiosyncrasies) to the touch sensitive screen substrate has been a mighty labour. Interestingly enough, a commenter to the article states that many smart phones do not detect degrees of pressure, just the fact of the pressure itself..