1 / 22

MIDI Hero: An Intuitive MIDI Controller with Auto-Harmonizing Note Selection

MIDI Hero: An Intuitive MIDI Controller with Auto-Harmonizing Note Selection. Matthew Campbell Brian Granaghan Benjamin Adcock Eleazar Kenyon. Project Advisor: Dr. William D. Hunt. Georgia Institute of Technology School of Electrical & Computer Engineering.

ifama
Download Presentation

MIDI Hero: An Intuitive MIDI Controller with Auto-Harmonizing Note Selection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MIDI Hero: An Intuitive MIDI Controller with Auto-Harmonizing Note Selection Matthew Campbell Brian Granaghan Benjamin Adcock Eleazar Kenyon Project Advisor: Dr. William D. Hunt Georgia Institute of Technology School of Electrical & Computer Engineering MIDI Hero Design Project Preliminary Design Review

  2. Project Motivation: Non-Musical Demographic • 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 MIDI Hero Design Project Preliminary Design Review

  3. Project Motivation: Musicians • 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 MIDI Hero Design Project Preliminary Design Review

  4. Project Description • 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 MIDI Hero Design Project Preliminary Design Review

  5. Cost Analysis *Labor Cost is calculated based on 4 engineers working 6 hours a week for 13 weeks at $30/hr. MIDI Hero Design Project Preliminary Design Review

  6. Design Objectives • 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. MIDI Hero Design Project Preliminary Design Review

  7. Design Overview • 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 MIDI Hero Design Project Preliminary Design Review

  8. Design & Implementation:Auto-Harmonization Algorithm • 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 MIDI Hero Design Project Preliminary Design Review

  9. Background: Basic Music Theory • 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 MIDI Hero Design Project Preliminary Design Review

  10. Note Selection Process MIDI In Determine key, Choose notes • Our algorithm will take chord information from MIDI in and choose notes from pentatonic scale MIDI Hero Design Project Preliminary Design Review

  11. Implementation: Restricted Note Selection MIDI Out Touchpad • User can use touchpad to select from available notes • User selection sent to synthesizer via MIDI output MIDI Hero Design Project Preliminary Design Review

  12. MIDI Hero Physical Design Dimensions: 13” x 11” x 4.75” Weight: ~6 lb.

  13. Top View LEDs LCD RPG Touch Screen

  14. Back View MIDI Out MIDI In On/Off Mode Selection VDC

  15. Design & Implementation:Touchpad Interface • 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 MIDI Hero Design Project Preliminary Design Review

  16. Design Challenges:Two Axis Coordinate System • 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 MIDI Hero Design Project Preliminary Design Review

  17. Design Challenges:Fall Time of Touchpad • 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 MIDI Hero Design Project Preliminary Design Review

  18. Design & Implementation:Configuration with LED/LCD/RPG • 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 MIDI Hero Design Project Preliminary Design Review

  19. Design & Implementation:MIDI I/O • 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. MIDI Hero Design Project Preliminary Design Review

  20. UART Utilization • 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. MIDI Hero Design Project Preliminary Design Review

  21. Milestones & Scheduling MIDI Hero Design Project Preliminary Design Review

  22. Future Improvements • Reduce physical form factor • Metal/Plastic Housing • Multi-touch capability • Enable user programmable chord patterns • Integrate with AutoCOMP Chord Detection • Upgrade processor • Implement integrated audio synthesizer and DAC MIDI Hero Design Project Preliminary Design Review

More Related