Technical Analyses
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Transcript of Technical Analyses
Gearing Torque
Force on pedal = 13 lbf(-13 lbf)(8”) – B(2.5”) =0 ⇾ B = -41.6 lbf(-41.6 lbf)(10.5”) + (F)(16.5”)= 0 ⇾ F = 26.47 lbf
Force Required to Lift Mutes
For Key A4: f = frequency =440 HzL = length = 15 inD= diameter of string =0.039 = density =0.282 lb/in^3
Calculating String Tensions
Frequency of each string needs to be analyzedElectret microphone will transform in into ac signal FFT performed to analyze occurrences of each frequencyGoal is to get voltage to rise linearly with frequency
Lead Screw Torque
Frequency of Strings
r = Ratiop = Octavecents = 1200 equal intervalsPn = Frequency of noten = piano key number (from 1 – 88)Pa = Reference Frequency (A)
To find the frequency of the 40th note (indicated by a blue key) using the 49th note (shown as a yellow key) as a reference
Step 1: Motors move the tuning mechanism along rails to the desired tuning peg, engaging it by means of a socket head attached to a motor shaft
Step 2: A solenoid lifts the mute lever, raising felt mutes off of the strings and allowing them to resonate
Step 4: The motor attached to the socket head turns the peg in the direction required to correct the pitch
Step 5: The mutes are released and the system moves on to the next peg
Step 3: A small solenoid strikes the associated string; its pitch is determined via Digital Signal Processing
Machine StartPeg Location
ProcessMute Released
String Striking Process
Frequency Determined
Frequency Correct?
String # Set to x=x+1
Last String?Machine Stop
No
No
Sharp or Flat?
Peg Turned Clockwise
Flat
Peg Turned Counter-
ClockwiseSharp
Mute Engaged
String Location Process
Yes
Yes
Peg Engaged
Peg locator process initiated
Coordinates for String # are read
X-Motor Moves Tuner to
X-Coordinate
Y-Motor Moves Tuner to
Y-Coordinate
Peg Location Complete
String Location Process Started
Coordinates for String # are read
θ-Motor moves Striker to position at angle θ from
corresponding peg
String Location Complete
The EasyKeys Team Mechanical Engineers:
- Tom Oliphant- Victoria Theese
Electrical Engineers:- Patrick Rienzo- Russell Jones- Kieran Walters
Faculty Advisor:- Professor Charles Geraldi
String Engagement
Process Started
Socket lowered onto tuning peg
Spring disengaged?
Process Ended
Yes
Motor Turned
No
Peg Location System
String Location System
Peg Engagement System
Legend:1. Track for Tuning / Striking Mechanisms2. Frequency Detection Subsystem3. Mute Lifting Subsystem4. Microcontroller
Overall System
The goal of this project is to create a device capable of tuning a piano without human aid
Mechanical Objectives:Remove mutesMove between pegs and stringsDiscreetly integrate into piano
Electrical Objectives:Design power circuitsImplement pitch-determination systemDevelop control algorithm Drawings made for all
machined parts (M-XX ): X-, Y-, and Z-axis
rails X-, Y-, and Z-axis rail
supports Rail slides Support plates Motor mount platesPurchased Parts (P-XX on drawing):
Lead screwsMcMaster-Carr
Theta motor Oriental motors - P/N 3TK6GN-AW2U
X,Y, and Z motorsOriental Motors – P/N SMK237A-A
Finalized Design
Final Drawing of System
Stronger material required for rails Smaller motors required Position of the tuning socket must be adjustable in
order to to reach all the pegs
File patent application Design market-ready version
Enable the system to reach all of the pegsUtilize more suitable materials and motors Increase speedDecrease noiseDecrease sizeDesign housing for the systemMake the system removable
“Ideally, acoustics should be tuned on a weekly basis, and right before all performances as well. However, tuning is expensive and time consuming (…) Generally, the pianos (in the music room at Stevens) get one tuning per semester. This is just not enough, and yet, it's what the program can afford.” -Bethany Reeves, Director, Stevens Choir
A single professional tuning takes 60-90 minutes and costs over $100. The average piano needs to be tuned twice per year, but pianos in recording studios may need to be tuned a few times each week.
Verified correct function of individual components Ensured smooth movement over entire range-of-
motion Tested frequency determination subsystem