A new positioning scheme for pen-like handwriting input devices

This paper introduces a new positioning scheme for pen-like handwriting input devices. With the use of passive references, positioning can be done in a more standalone manner with lower system complexity. In this scheme, the system is made up of a pen-like device with a single omnidirectional wireless transceiver located near the tip and a writing tablet with several reflectors embedded at its edges as references. The omni-directional transceiver keeps transmitting short wireless pulses and receiving echoes from the passive references. Using the proposed simple self-localization method, the 2D position of the pen-like device can be obtained solely from the received echoes that contain no directional information. Simulation results using ultrasound as the wireless medium have shown that it is capable of recognizing handwritten input characters accurately.