After several rounds of iteration, we decided to build our tuner into the guitar. Using a torque sensor, we experimentally determined that we needed a motor to supply 3.7 lb-in of toque; hence, we used six AR-3606HB continuous servo motors.
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Custom-designed adaptors were machined to connect the pegs to the motors.
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The motors and electrical components are housed in a casing made of two 3D printed housings clamped together.
Mechanical Components
Electrical Components and Coding
We used a electret microphone amplifier with adjustable gain to pick up the sound wave. By implementing fourier transform, we isolate the frequency that the string is at. The frequency identifies which string to tune. After finding a relation between the duty cycle and the error of the frequency, we send an input to the Arduino Uno to turn the motors and hence the pegs, tuning the pegs to the correct frequency.
Hardware Setup
