Is it true that someone before Louis...

Yes and no. Charles Barbier, a captain in Louis XVIII’s army, invented a system of night writing intended for sentinels to use to communicate with each other in the dark. His code consisted of dots and dashes in relief on soft cardboard. Barbier later brought his code to the Institut National des Jeunes Aveugles (Royal Institution for Blind Children), where the young Louis Braille was enrolled. Braille, who had gone blind at the age of three as a result of an accident, took up Barbier’s code and began to improve on it. Braille’s version used a “cell” of six dots that could be arranged variously to represent the letters of the alphabet, punctuation marks, mathematical symbols, and so forth. The system was later applied to musical notation as well, since Braille was also an accomplished musician.