The first implementation of the Computer Controlled Precision Piano Tuner (CCPPT) is shown in
Figure 1 in the 1992 ICSPAT paper.  An updated concept is shown below wherein available
modern (2002) tools are used to acquire and process the audio data.

 


In addition, the means of rotating the piano's tuning pin has been revised in order to get the noisy
stepper motor away from the source of the piano sound.  The socket (on the output of the worm gear box)
which engages the piano tuning pin is also more easily maneuvered.


Below are pictures of the mechanism used to turn the piano tuning pin.
The audio data acquisition is not shown here.
Stepper motor on right connects through a flexible shaft to a worm gear box.
The gear box output shaft connect directly to a tuning pin on the piano.
Another view of the worm gear box.
A close-up of the worm gear box showing the connection with the torque restraining bar.
The torque restraining bar clamps to the frame of the piano.  The white wire is a connection to a strain gauge mounted in the middle of the bar.  The strain gauge indicates to the PC control program the amount of strain in the torque restraining bar.

The U-joint allows the whole mechanism to be moved to any tuning pin on the piano.