Development Of Tactile Vision Substitution System Based On The Fingertips

The World Health Organization estimates that there are about 450 millions blinds all over the world. According to the investigation to the vision blinds, there are 55 millions blinds in china. So based on the belief of technology benefit human, the scientists from different nations try their best to restore the blind using the technology and engineering. Tactile vision substitution system (TVSS) intends to stimulate the skin with electrode array so that the blind will have a tactile perception. This paves a new road for the blind to regain visual information through the two-dimensional distribution of electro-tactile stimulation.This paper will introduce the design procedure of the multi-channel TVSS, which consists of three modules: Electro-tactile electrode array, Electrode drive circuit and Embedded control image processing module. The electrode array of 256 channels is made by welding spherical nickel electrodes to the printed circuit board. By using the multiplexing technology can we provide the 256-channel electrode array with high-voltage pulse stimulation, and the optoelectronic isolation circuit serves as isolator and controller between strong current and weak current signal. The DM642 development tools can help to achieve the functions of the acquisition, processing and transmission of the images. After building up the system, we carry out some preliminary experiments. The results show that: the threshold of the high voltage stimulation on the fingertips is more than 130V, and the width of the pulse could cause the change of threshold and effect of the stimulation. More than 150V could cause a comfortable and local electrical touch. We could get a better tactile sensation to the simple shapes with the array of 6×6.