Abstract: Aiming at the problem that people with audio-visual disabilities could not obtain the information of mobile devices through tactile interaction, we proposed a method to encode the information on mobile devices by using vibrotactile signals with multiple perceptual intensities, which was used to distinguish the types or contents of information. Firstly, the sensing intensity of the frequency, duration and interval of the vibrotactile signal were determined by testing the sensing threshold, and the signal was adjusted to an acceptable level. Secondly, according to the difference of subjective perception intensity and the encoding combination mode, equal-length code and variable-length code were proposed  for the tactile coding transmission of information. Finally,  the recognition results of limited coding information were evaluated by information theory. Experimental results show that this method can improve the accuracy of information tactile judgment, and the variable-length code has better recognition rate and transmission efficiency than the equal-length code.

Key words: coding information, vibrotactile signal, psychophysics, information theory, mobile device