IMPLEMENTASI KENDALI PID DALAM PENALA NADA GITAR OTOMATIS IMPLEMENTATION OF PID CONTROL ON AUTOMATIC GUITAR TUNER

Proportional � Integral � Derivative Controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control systems. PID is the most commonly used feedback controller. A PID Controller calculates an \"error\" value as the difference between a measured process variable and a desired set point. The controller attempts to minimize the error by adjusting the process control inputs. System that has been made is an automatic guitar tuner that applied a simple PID controller using sound sensor module as its input device. Sound sensor will sense the guitar string�s sound vibration and convert it to a certain voltage for a processing unit to read. Then, the processing unit will count the sound�s frequency which represents the picked guitar string�s tone using the counting zero-crossing method based on the voltage change that happened earlier. The error value between measured frequency and setpoint will be used as an input for the control system. Its outputs are speed and direction of a stepper motor that coupled and spins the picked guitar peg until the error value reaches zero. System tests are done by testing the sensor placement effect on system performance and testing the PID control characteristics. The best sensor performance results are achieved by placing the sensor attached to guitar tube with 99,74% accuracy of frequency counting. From the test result, it is known that this system�s optimal gain values are: Kp = 3, Ki = 1,5, and Kd = 2,5. This system is capable to tune a guitar in average time of 11,2 seconds each string