Optophone

The optophone is a device, used by people who are blind, that scans text and generates time-varying chords of tones to identify letters.

Dr. Edmund Fournier d'Albe of Birmingham University invented the optophone in 1913,[1] which used selenium photosensors to detect black print and convert it into an audible output which could be interpreted by a blind person.

The Glasgow company, Barr and Stroud, participated in improving the resolution and usability of the instrument.

[2] Only a few units were built and reading was initially exceedingly slow; a demonstration at the 1918 Exhibition involved Mary Jameson reading at one word per minute.

[3] Later models of the Optophone allowed speeds of up to 60 words per minute, though only some subjects are able to achieve this rate.