Most e-book readers don’t have physical page turn buttons. Why? They just don’t. Virtual page turns are accomplished with a tap at a screen edge. Determined to reduce the awkwardness of one-handed use, [Sagar Vaze] modified a Kobo e-reader with two physical page turn buttons as a weekend project.
[Sagar] points out that since the underlying OS of the Kobo device is Linux, it is possible to fake touches to the screen (and therefore trigger page turns) by recording then replaying the appropriate input event. However, there was a more direct solution available to those willing to tamper slightly with the hardware. Touch sensing on the screen is done via an infrared break-beam system. Along two edges of the screen are IR emitters, and opposite the emitters are receivers. Broadly speaking, when a fingertip touches the display a minimum of two IR beams are broken, and the physical location of the fingertip can therefore be determined by analyzing exactly how the IR pattern has been changed.
To spoof page turns, [Sagar] briefly shorts two IR emitters: one on each axis. The sudden winking out of the IR is interpreted by the device as a crisp tap, and the device obediently turns the page. The only hitch is that both IR emitters must be shorted at the same time. If one is shorted before the other, the device ignores it. Double-pole switches would probably do the trick, but with the part bin coming up empty in that respect, [Sagar] instead used a few transistors to accomplish the same thing. A 3D printed enclosure rounds out the whole mod, and a brief video is embedded below.