Transcript Detailed Design Review

Detailed Design Review
Project P13363
Members:
Justine Converse (IE)
James Cover (CE)
Alexander Eschbach (EE)
Jason Hang (ME)
Ashley Trode (EE)
Guide: Gerald Garavuso
Our Focus
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Mount sensor on 2 keys (1 white and 1 black key)
Microcontroller will be able to get input from sensor and output a
MIDI recognizable signal
Sensors will be mapped in two dimensions to be able to control two
separate music parameters. One dimension will be able to change a
user selected parameter (i.e. volume, vibrato, etc.) over each
individual key and the other dimension will change pitch bend over
all keys at the same time
MIDI mapping will be the limitation to which parameters can be
mapped
Will use blackberry trackball for sensor
Engineering Specs/Requirements
System/Flowchart
System Diagram
What we decided last time
Conduct further research and testing for two
concepts...
*Blackberry trackball/trackpad
*Capacitive touch sensor
Capacitive Touch Testing (Initial)
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Simple RC circuit built
with square wave
input
Touched leads of the
capacitor
Discovered that
touching both leads
has a more
noticeable effect
Capacitive Touch Testing (Initial)
• One capacitor testing
• Rise time changes if a touch exists
• Left (no touch), Right (touch)
Capacitive Touch Testing (Sensor)
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Touchpad breakout board is from
sparkfun
Twelve electrode capacitive touch
inputs per chip
Microcontroller is needed to interpret
the signal
Microcontroller can tell when
touchpads are contacted and when
they are released
The time touched could be used for
sensitivity
Schematics - Capacitive Touch
Circuit
Trackball Testing (Sensor)
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Trackball breakout board is from sparkfun
4 directions and a push button can be detected and outputted as a digital
signal using four hall effect sensors and a push button
The frequency of the digital signal is controlled by the speed of the
trackball
The position can be found by counting how many digital highs there are in
a certain amount of time
Schematics -Trackball Circuit
Risk Assessment
Decision Based on Testing & Risks
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Move forward with Trackball Sensor
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Easier to program
 Repeatable results
 Less data to manipulate
Schematics - Main Circuit Board
Will consist of
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Microcontroller (still need to pick)
power regulator
inputs of trackball sensors
MIDI circuit
Pseudocode (Interface Test Program)
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Initialize Microcontroller
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Board Setup (Pin IN/OUT)
Interrupt Setup (Enable, Edge trigger)
Wait for interrupt from trackball
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Turn on LED
Delay
Turn off LED
Clear Interrupt
Pseudocode (System)
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Initialize Microcontroller
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Wait for interrupt from trackball
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Board Setup
Interrupt Setup
System Setup
 Buttons to change parameters
 Sensitivity
 Musical parameter per axis
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Start timer
Count number of rotations in time period
Determine magnitude + speed
Modify incoming MIDI signal
System Diagram
Timing Diagram
Pseudocode - MIDI
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Send 'Note On' Message
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Key press
Send 'Aftertouch' Message
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Sensor data
Send 'Note Off' Message
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Release key
MIDI - Background
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MIDI - Musical Instrument Digital Interface
An electronic musical instrument industry standard
protocol set in 1983
Allows for easy communication and compatibility
between digital musical instruments, computers, and
other related devices
Captures note events and music parameters
adjustments and encodes them in a digital message
This digital message can then be interpreted and
decoded into music
MIDI - Types of Messages
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Channel Messages - used for controlling one or more of
the 16 MIDI channels or for controlling musical notes
using a specific MIDI channel
System Exclusive Messages - longer MIDI messages
that are used for a variety of purposes
System Common Messages - Some standardized
features that are used for controlling the playback of
songs in MIDI format
System Real-Time Messages- Used for timing and
clock signals
MIDI - Channel Message Digital Signal
MIDI - Issues
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Individual control of certain parameters is
impossible within the MIDI specification
Creating a message that complies with the
MIDI specification that other devices will
understand
MIDI - Resolution
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Additional software is required for full control
of all parameters
Find contacts that know more about the MIDI
specification or know where to find related
resources
o Music shops
o RIT library
o Manufacturers
o Organization that controls/owns standard
Test Plan (Software)
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Play 1 key without sensor, get output
Play 1 key with sensor, get output
Fast and short
o Fast and long
o Slow and short
o Slow and long
o Sensitivity
o Multidirectional
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Play two keys, get output
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One with sensor, one without
Both with sensor
Test Plan (Hardware)
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Unaltered keys
o Normal Play
 Have a pianist play the keyboard normally
 Measure the forces applied to the keys
o Maximum Play
 Play the keys aggressively
 Measure the forces applied on the keys
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Altered keys
o Normal Play
 Apply the force measured from playing normally
o Maximum Play
 Apply the force measured from playing aggressively
High Level Plan
• Overall system
plan for the
location of the
components
o Sensor
o Wires
o Microcontroller
circuit board
Microcontroller
circuit location
Placement of Sensor on Key
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Discussed where pianist place their fingers when
playing.
Realized that there is no set location, usually all over
the keys.
Determined where NOT to place the sensors.
Constrained to structure of the white and black key.
Black key has a very limited amount of space.
Extra material necessary to support sensor as well.
Key Drawings
- SolidWorks Model of keys
- SolidWorks Model key
insert
Key Drawing
• SolidWorks Model of black key with key
insert, PCB board and trackball sensor
Drawing of the Key Insert
Bill of Materials
Plan for MSD II
Conclusions/Questions
Electrical
How to create a MIDI recognizable signal,
will our design work?
Choice in microcontroller
Do the capacitors and resistors need to be
close to the hall effect sensors?
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Mechanical
Best way to put sensor into key?
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