P18363: Player Piano 2

Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase

Plans for this phase as defined in the Systems Design Phase were primarily individual. In particular, the goals were:

As well as any other tasks that were outlined in the plans for prototyping from our last phase and in the presented Gantt Chart.

Updated Concept Sheet


Click here to download the Concept Development spreadsheet: Concepts Sheet

Solenoid Force Test Results

Using the data below, it was decided that to encompass the dynamic capabilities to satisfy the requirements, the solenoids chosen should be able to achieve a force of 30N. public/Preliminary%20Detailed%20Design%20Docs/researchplots.png

Click here to download the research paper on the characteristics of keystroke force in a piano: Keystroke Force Research

A force test was completed on the solenoid's from last year, using the direct push method on the hammer of a note in the middle octave and low octave. The data shows that decibel level output and voltage had a positive correlation, and that dynamic range was possible.


The image below shows the data sheet and force test results for the solenoid model that would have made it possible to avoid staggering to hit each hammer. public/Preliminary%20Detailed%20Design%20Docs/solenoidlowoption.pngpublic/Preliminary%20Detailed%20Design%20Docs/forcetestsolenoidlow.png

Click here to download the data sheets for the solenoids provided by Ledex Tubular for Linear Solenoids: Johnson Electric Data Sheets

The following data sheets are for solenoids that would require staggering but output higher force. public/Preliminary%20Detailed%20Design%20Docs/solenoidmidoption.png public/Preliminary%20Detailed%20Design%20Docs/solenoidhighoption.png

Solenoid Control Options

Option 1: Build a custom PWM constant current control circuit


Option 2: Use Infineon's TLE7242-2G 4 Channel Fixed Frequency Constant Current Control IC


Option 3: Use TI's DRV110 V DC Current Controller for Solenoids


Option 4: Use TI's DRV8806 Quad Serial Interface Low-Side Driver IC



Previous Iteration Simulation of Circuit



Linear Actuator Options


  1. Apply at least 30lbs of actuation force
  2. Stroke displacement of at least 0.25 inches
  3. 0.5-1 second response time (fast travel rate)

Option 1: Thomson Linear DE12-17W41


Option 2: Actuonix P16-P



Option 1:

Option 2:

Solenoid CAD Drawings

Overall View of System


Click here to download this picture: Overall View

Click here to download the 3D Model: 3D Model

Side View of Staggering


Click here to download this picture: Side View

Close up on Solenoids


Click here to download this picture: Close Up

Software Design

The current UI looks like this:

public/Preliminary%20Detailed%20Design%20Docs/UI capture.PNG

Here is a UML Diagram of the current server code:


And here is a revised document containing the changes that we plan to make:


Server Research

Bill of Material (BOM)

Low Cost Option


Current Design Option


High Performance Option


Click here to download our BOM Spreadsheet: Bill of Materials

Test Plans


Click here to download the updated Risk Management spreadsheet: Test Plan Spreadsheet

Systems Architecture

Detailed Version


Solenoid Control Logic


Linear Actuator Design


Timing Diagram

If we expect to be able to play notes at a resolution of 10ms, all configuration data for each solenoid must be communicated within that time. public/Preliminary%20Detailed%20Design%20Docs/serial_keys_waveform.png

Controlling the Enable pin for all solenoid drivers requires 88 bits to be transmitted. The ADC voltage control needs 12 bits per channel and takes much longer to transmit. However, not all ADC channels need to be written every cycle (being able to update 20 channels in 1 cycle would be sufficient to meet our requirements).

Risk Assessment


Click here to download the updated Risk Management spreadsheet: Risk Management Spreadsheet

Project Plan


Plans for next phase

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