Here's one guess, from out of a relatively recent SCE patent - a new type of button.
[0047] An embodiment of the invention includes a new class of button style inputs for use in hand based video game input devices which leverages existing technology to detect 3 axis of pressure sensitivity. These buttons would be used in place of or in conjunction with in place of the traditional action buttons (i.e., .DELTA. .quadrature. OX) on device such as the Wavebird, Dualshock 1&2 and the X-Box controller which are either only digital or 1 axis analog sensors. These sensors are static NOBS which can recognize analog pressure from left and right (x.sub.1-x) forward and back (y.sub.1-y) up and down (z, -z). This leads to robust analog input in three axes.
[0048] Current digital buttons are severely limited input mechanisms and the single axis analog buttons are underutilized (most users are unaware of this functionality) and they don't have enough fidelity to impart subtle control. Thus when possible, people tend to use analog sticks. As a result, with single axis buttons, most gameplay skews to full pressure being best pressure, at which point the buttons might as well be digital, rather than analog, input devices. Three axis of analog control would allow for complex input even with poor fidelity.
[0049] Imagine a tennis game: digital button-only imports if user swings or not, single axis analog--allows for one type of swing with varying levels of power, 3 axis analog--allows for swing strength, for all swing types and at least 4 additional controls to be used for spin (English) or stroke type (forehand, backhand, lob, spike). The argument for 3 axis buttons (over single analog or digital) is directly analogues to the argument for analog sticks over "D-Pad."
[0050] To implement these new "buttons" apply existing technology from aerospace. Replace current action buttons and provide appropriate drivers to allow developers to leverage up to 3 axis of control. Would suggest visually differentiating from current family of gamepad buttons so it doesn't suffer from user oversight as current analog buttons have.