Chorded keyboard (a writing system for the blind) uses either 6 or 8 tactile 'points' from which all letters and numbers are formed. When Louis Braille invented it, it was produced with a needle holing successively all needed points in a cardboard sheet. In 1892, Frank Haven Hall, superintendent of the Illinois Institute for the Education of the Blind, created the Hall Braille Writer, which was like a typewriter with 6 keys, one for each dot in a braille cell. The Perkins Brailler, first manufactured in 1951, uses a 6-key chord keyboard (plus a spacebar) to produce braille output, and has been
Slate and stylus Children) the first book ever published for the blind. Prior to 1786 tools for the blind to read or write were the results of individuals personal approaches to solutions. One of the more notable approach was that of Nicholas Saunderson (Lucasian Professor of Mathematics at Cambridge) blind nearly from birth, devised an Arithmetical slate. Braille evolved from the night writing of Charles Barbier. "Ecriture Nocturne" (night writing) was invented in response to Napoleon's demand for a code that soldiers could use to communicate silently and without light at night. Because it used a cell with 2 columns of six dots