P19363: Player Piano

Systems Design

Table of Contents

Team Vision for System-Level Design Phase

Plans for this phase defined 3 weeks ago:

Accomplishments of this Phase:

Functional Decomposition


The Benchmarking table above is based off of the Benchmarking table completed in the previous year.

Morphological Chart and Concept Selection

Functional Decomposition

Concept Development



Least Invasive

Least Expensive

Perfect Universe Scenario

Concept Selection

Feasibility: Prototyping, Analysis, Simulation

Based on the requirements, the most important things the chosen concept should deliver on are: increasing volume range of the notes produced when the system plays the piano reducing the noise the plunger makes when solenoids are in use reducing the delay between when the note is expected to be played and when the note is actually being played providing feedback to the user (i.e. matching any changes the pianist makes while playing the song) actuating the sustain pedal of the piano These requirements need to be met while keeping in mind the constraints (i.e. the two semesters of senior design, the budget, the space within the piano and the inability to permanently modify the piano) and addressing the pitfalls of the previous concept (e.g. power delivery).

A PWM IC was chosen as the way to increase the volume range of the notes produced. The PWM IC should give better control to current being delivered to the solenoids. The more current the solenoids receive the faster the plunger travels and by extension the faster the hammer in the piano travels.This should result in increased volume range as observations show that the velocity of the mechanism hitting the strings in the piano determines the volume of the note produced. The voltage dependent resistor was not chosen as it would mean another set of components in the already limited space inside the piano. The higher rated solenoid was not chosen as it would require more power delivery which seems to be an issue with the current system.

Adjusting the stroke length of the plunger and adding foam around the back cover and casing of the solenoid was chosen as the way in which the noise of the plunger will be reduced. Adjusting the stroke length will stop the plunger from hitting the back cover of the solenoid which is what is causing the noise. Adding foam on the back cover adds a failsafe if the plunger is travelling too fast to be stopped by the spring. The cover was not chosen as it masked the noise instead of stopping what was creating the noise. The vacuum tubes were not chosen as multiple would be needed and thus more of the budget would be needed.

Optimizing the code and having the microcontroller be able to predict future tasks was chosen as the way in which the delay will be reduced. The current system assumed that the delay was static, this was not true. If the code is rewritten to account for the variations in delay and the microcontroller can also predict future commands and the delay in response to these commands then the delay between the note being expected and the note being played should be reduced. The other solution, new board design, was chosen as the solenoid controller. A new board design could solve the problem of power delivery any issue would be known and could be worked around if necessary. This is as opposed to the current system were cause of the power delivery problem isn’t known.

Microphones were chosen as the sensor to be used to record the volume and tempo so that it may be matched with the music being played by the pianist. With regards to volume, there was no solution that measured the intensity of a sound that did not use a microphone. With regards to tempo, microphones were chosen as accelerometers would need to be mounted on some part of the system hitting each string of the piano. This would modify the piano and could affect its ability to function normally. Microphones were also chosen as less microphones were needed (when compared to the accelerometer) thus there would be less points of failure in the system. And less of the budget would need to be devoted to microphones when compared to LiDARs and the number of accelerometers needed.

A linear actuator was chosen as the device that would control the sustain pedal of the piano. The other solutions were not chosen as the linear actuator in the current system was deemed sufficient. The other solutions would require more time to be used selecting, testing and integrating other components into the system. And they would require more of the budget to be devoted to controlling the sustain pedal.

Systems Architecture

Risk Assessment

public/Photo Gallery/Risk Chart.PNG

Plans for next phase

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