It is becoming increasingly difficult for users to interact with the slew of portable gadgets they carry, especially in the area of text entry. Although miniature displays and keyboards make some portable devices, such as cell phones and PDAs, amazingly small, users’ hands do not shrink accordingly.
To solve this problem, we proposed a Virtual Keyboard. This device will replace a physical keypad with a customizable keyboard printed on a standard A4 size paper whose “keystrokes” are read and translated to real input. This virtual keyboard can be placed on any flat surface, such as desktops, airplane tray tables, kitchen counters, etc. and can theoretically be interfaced with any computing device that requires text entry. This would eliminate the need to carry anything around and also prevent any chance of mechanical damage to the keypad in harsh environments if a simple lamination is used to protect the paper.
The Virtual Keyboard has three main components:
- The laser
- Printed keyboard.
The laser beam is simply a conventional off-the-shelf red laser with a line-generating diffractive optical element attached to it. This assembly generates an invisible plane of red light hovering a few millimeters above the typing surface. When a finger passes through this plane, it shines bright red in that region.
The CMOS camera continuously captures images of the region where the printed keyboard is supposed to be placed and checks these images for red color data above a specified threshold. The threshold concept works in this case because the laser shining on a typical human finger generates saturating values of red color data, which is very easily distinguishable from its surroundings. Lastly, the printed keyboard is simply a standard A4 size paper that contains a custom keyboard layout.