Motorized guitar tuner

http://people.ece.cornell.edu/....land/courses/ece4760
The Mechanix is a motorized guitar tuner for a standard 6-string electric or acoustic fixed bridge guitar. Traditional handheld guitar tuners are passive; they tell the user whether the guitar string is in tune, sharp, or flat, but the actual adjustment of the tension in the string has to be done by the user. This requires a fair amount of dexterity from the user, particularly when fine tuning is required. Thus, to increase both the convenience and the precision of the tuning process, we designed an active, motorized guitar tuner. The Mechanix responds to the user plucking one of the strings by turning the tuning knob until the string has reached its Standard Tuning note.