Conveying directional information through vibrotactile stimulation

A crucial aspect in the design of navigational aids for the blind is the transmission of information to the user. Vibrotactile stimulation is a preferred means, as opposed to auditory stimuli that may interfere with the use of environmental auditory cues for situational awareness. Conveying directional information is of particular importance and has traditionally be achieved with several tactors being positioned around the waist of the user, with each tactor coding for one direction. In contrast to that approach, we have explored ways of representing directions with nearly continuous angular resolution using only two tactors. Such pairs of tactors could be integrated into handles of rollators for frail elderly blind people or could be placed into pant pockets, making the cumbersome use of vibration belts obsolete. Because pilot experiments revealed that information transmission through vibration amplitude lacks accuracy and reliability, we tested three different temporal coding schemes.