A direct translation reading aid for the blind

A reading device for the blind is proposed in which a facsimile of ordinary printed material is presented tactually. The tactile image is presented by a dense array of pins which can be made to vibrate individually through perforations in a plate on which the user´s finger is rested. In the arrangement proposed, the image of ordinary printed matter is focused on an array of photocells which are coupled one-to-one to piezoelectric reeds which drive the image-producing pins. The feasibility of this arrangement has been evaluated, and relations among the design parameters are derived. The power required to drive each pin for adequate tactile stimulation is shown to be only about 30 µW. Present photocell sensitivities and integrated circuit techniques appear to be adequate for a convenient microminiature realization of this arrangement, although several technical development problems remain to be solved. Successful reading tests with blind subjects are reported in which a computer controller simulates the optical portion of the system. The tactile images presented on a field of 96 piezoelectrically driven pins have been readable by the three subjects tested at rates of about 30 correct words per minute.