Novel flexible pressure sensor combining with dynamic-time-warping algorithm for handwriting identification

A novel handwriting identification technique, consisting of a flexible piezo-resistive pressure sensor with micro-pyramid structures and a Dynamic-Time-Warping algorithm, was presented in this paper. Real-time dynamic pressure was recorded by the piezo-resistive pressure sensors and similarities of characters written by different volunteers were evaluated using the Dynamic-Time-Warping algorithm. The piezo-resistive sensors were fabricated on polyimide thin films with designed micro-pyramid structures and the single-wall carbon nanotubes coated on the polyimide substrates were used the sensitive materials. It is found that the size of the micro-pyramid on polyimide substrates and film thickness have a significant influence on device performance. A device with a wider sensitive range (0–20 kPa)was fabricated with the optimized fabrication conditions and it is able to distinguish signatures of different volunteers correctly. Therefore, the device presented in this work shows an essential potential in the applications of the handwriting identification system.