Transfer function of electromechanical-tactile stimulation

The overall transfer function for a tactile vision information system (TVIS) used as an aid to the visually impaired is described. Included in this transfer function are the electromechanical vibrators, the skin interface, and the tactile skin sensors. In previous work, individual components have been analyzed, but no attempt has been made to evaluate the process in its entirety. Each transfer function is also analyzed in detail to describe the input-output relationships important in the effective transfer of optical information in a TVIS. The overall transfer function is developed and its equation is given. Here, a theoretically derived stimulation waveform was used for the vibrator driving current. Under computer simulation, this waveform reduces the vibrator noise levels to less than 70 dB(C) while requiring only 3 mW of power for each vibrator to elicit tactile sensation.<>