Matthew Campbell Brian Granaghan Benjamin Adcock Eleazar Kenyon 3/16/2010 MIDI Hero Design Project...
-
Upload
barrie-gallagher -
Category
Documents
-
view
215 -
download
0
Transcript of Matthew Campbell Brian Granaghan Benjamin Adcock Eleazar Kenyon 3/16/2010 MIDI Hero Design Project...
Matthew CampbellBrian GranaghanBenjamin Adcock
Eleazar Kenyon
3/16/2010MIDI Hero Design Project
Preliminary Design Review 1
Project Advisor: Dr. William D. Hunt
Georgia Institute of TechnologySchool of Electrical & Computer
Engineering
Current highly successful products include:◦ Rock Band◦ Guitar Hero
Appeal:◦ Provides an interactive musical experience for the
musically unskilled
Shortcomings:◦ Restricts users to “playing” a limited number of
preprogrammed songs◦ Cannot be integrated with live music◦ Does not allow improvisation
3/16/2010MIDI Hero Design Project
Preliminary Design Review 2
Current highly successful products include:◦ Korg Kaoss Pad
Appeal:◦ Provides a versatile platform to add simple
harmonies
Shortcomings:◦ Requires musical experience◦ Does not restrict note selection
3/16/2010MIDI Hero Design Project
Preliminary Design Review 3
MIDI Hero◦ Generates MIDI output from touch input◦ Allows user to develop simple accompanying
harmonies with minimal effort.◦ Enables friends and/or audience members to
accompany a musician in a live performance.
Will be marketed to musicians◦ Live performances (coffee shop, etc.)◦ Casual jam session (friend, child, etc.)
Retails for approximately $330
3/16/2010MIDI Hero Design Project
Preliminary Design Review 4
Item Price
Labor Costs of Development* $9360
5-Wire Touchpad $58.00
Product Housing $15.00
AC Adapter – 12V,1.5A $6.98
PCB $47.50
AVR Programmer $34.00
Other Components $11.29
Parts Total………………………………
$172.77
Grand Total…………………………….
$9532.77
Average Variable Cost……………….
$228.77
3/16/2010MIDI Hero Design Project
Preliminary Design Review 5
*Labor Cost is calculated based on 4 engineers working 6 hours a week for 13 weeks at $30/hr.
*Labor Cost is calculated based on 4 engineers working 6 hours a week for 13 weeks at $30/hr.
Goals:
◦ Allow a musically unskilled operator
◦ to use an intuitive touch interface
◦ to choose from a range of restricted notes
◦ selected by analyzing chord information
◦ generating a single-note harmony
◦ and providing real-time accompaniment to a performing musician.
3/16/2010MIDI Hero Design Project
Preliminary Design Review 6
◦ MIDI input/output◦ Standalone/Slave
Modes◦ Touchpad note
selection◦ LED Tempo Indicators
(standalone mode)◦ Rotary Encoder
controlled menu◦ LCD Status Indicator◦ 13” x 11” x 4.75”
Housing◦ AutoCOMP Chord
Detector interface
3/16/2010MIDI Hero Design Project
Preliminary Design Review 7
• Western music follows a tonal structure• Musical score follows key and chord structure• Each key (e.g. C Major) consists of a root note
and six other tones• Chords consistent with a given key consist of
specific subsets of these seven notes
• Western music follows a tonal structure• Musical score follows key and chord structure• Each key (e.g. C Major) consists of a root note
and six other tones• Chords consistent with a given key consist of
specific subsets of these seven notes
3/16/2010 8MIDI Hero Design Project
Preliminary Design Review
• C Major chord consists of three notes (red)• Some notes (red and orange) sound pleasant
with any chords within the key of C• These five notes form a pentatonic scale
• C Major chord consists of three notes (red)• Some notes (red and orange) sound pleasant
with any chords within the key of C• These five notes form a pentatonic scale
3/16/2010 9MIDI Hero Design Project
Preliminary Design Review
• Our algorithm will take chord information from MIDI in and choose notes from pentatonic scale
• Our algorithm will take chord information from MIDI in and choose notes from pentatonic scale
MIDI InMIDI In Determine key,Choose notes
Determine key,Choose notes
3/16/2010 10MIDI Hero Design Project
Preliminary Design Review
• User can use touchpad to select from available notes
• User selection sent to synthesizer via MIDI output
• User can use touchpad to select from available notes
• User selection sent to synthesizer via MIDI output
TouchpadTouchpad
3/16/2010 11MIDI Hero Design Project
Preliminary Design Review
MIDI OutMIDI Out
8.5” x 6.5” 5-wire resistive touchpad
Axis Layout:◦ X Axis controls Pitch
(increasing from L to R)
◦ Y Axis controls note velocity (increasing from bottom to top)
◦ Output voltage digitized by ADC
3/16/2010MIDI Hero Design Project
Preliminary Design Review 15
Problem:◦ Single axis dynamic
reading capabilities Solution:
◦ Dynamically switch bias voltages Microcontroller alternatively
selects axis by inverting touchpad supply voltages Implemented using TTL
inverter
TTL implementation is effective, but causes reduced resolution
3/16/2010MIDI Hero Design Project
Preliminary Design Review 16
Problem:◦ Prohibitively large fall
time after finger is removed
◦ Screen acts as a capacitor, slowly discharging through ADC input
Solutions:◦ Ground ADC pin in
between sampling cycles
◦ Enables high time resolution readings
3/16/2010MIDI Hero Design Project
Preliminary Design Review 17
Enables device to operate as a stand alone system
Internal tempo displayed using LEDs Configuration parameters modified using
LCD and RPG◦ Tempo◦ Chord progression◦ Key
3/16/2010MIDI Hero Design Project
Preliminary Design Review 18
Signal Properties:◦ Asynchronous 31250 baud◦ 1.5 mA current loop◦ Opto-isolated; current on is logical 0◦ 1 start bit, 8 data bits, 1 stop bit
Data Stream:◦ Each message starts of a one status byte, which
specifies the message type and channel.◦ Subsequent bytes are parameters ranging from 0-
127; the highest bit is reserved for denoting if a byte is a status byte.
3/16/2010MIDI Hero Design Project
Preliminary Design Review 19
The ATMega328P features a single hardware UART.
Both MIDI and LCD are controlled via UART.
Potential Solutions:◦ Design and implement second UART in software
Requires additional pins, hence additional microcontroller Would increase cost and complexity significantly
Final Design Solution◦ Use tri-state buffer to control signal route, alternatively
addressing LCD and MIDI out.
3/16/2010MIDI Hero Design Project
Preliminary Design Review 20
3/16/2010MIDI Hero Design Project
Preliminary Design Review 21
Project Tasks & Milestones Completion Deadline
Software Implementation
Touchpad-ADC interface Completed
MIDI encoding and transmission Completed
Implement user menu/LCD/RPG interface April 2, 2010
Implement note selection algorithm April 2, 2010
Combine sub-blocks into final program loop April 9, 2010
Other Tasks
Construct Wooden Housing Completed
Finalize circuit schematic/assemble device April 9, 2010
Network MIDI Hero with AutoCOMP April 23, 2010
Testing and debugging April 30
Final design review and demonstration (tentative) May 3-7, 2010