Origin of Numerical Control [History]

Many senior citizens may remember the player piano where a perforated paper roll about 11.5 in wide was used to play music. As the perforations in the paper passed over what looked like a long harmonica, various notes would be played on the piano. In 1908, the harmonica device was modified to have smaller holes and spaced at 9 per inch. The control was pneumatic, and thus when a group of perforations in the paper passed over a hole in the harmonica device, preprogrammed music would be played. Of course, pinned barrels to operate things such as clocks were used many years before the player piano. However, the combinations of holes in the paper roll were the equivalent of a number scheme representing a song. The pneumatic system was operated by foot pedals to supply a flow of air. Thus, the player piano was an early concept of numerical control. The article discusses the continuing history of numerical control.