Short Paper

This Note introduces a keyboard design that affords ten-finger touch typing by utilizing a touch sensor on the back side of a device. Previous work has used physical buttons. Using a touch sensor has the benefit that it retains the form factor and does not insist on a peripheral device. Moreover, any layout can be used. However, it is difficult to hit targets on a flat surface with no haptic feedback. Sandwich Keyboard is a prototype that folds any three-row keyboard layout and thus, by retaining the finger-to-letter assignment, supports transfer. Sandwich Keyboard includes an algorithm for constant adaptation of key targets in the back. We also learned that the detection of key presses from finger release enhances the performance of touch-typing on a multitouch sensor. After eight hours of training, experienced typists of the QWERTY and of the Dvorak Standard Keyboard (DSK) layout reached 26.1 and 46.2 wpm, respectively. We discuss improvements necessary for further increasing both speed and accuracy.