Auto-chromatic Musical Instrument Tuner Craig Janus and Robert Schmanski Advisor: Dr. James Irwin

Presentation Overview Terminology Project Summary Functional Description Block Diagram Software Milestones & Critical Problems Future Work Progress Summary

Terminology Pitch / Fundamental Octave Tuning error Cents

Project Summary Determine pitch of note played Inputs- microphone, mode/power switch, and pitch selector Output- pitch indicator, analog and digital tuning meters, and speaker 8031 microcontroller

Functional Description Inputs –Microphone –Power / mode switch –Pitch selector

Functional Description (cont.) Outputs –Pitch indicator –Analog tuning indicator –Digital tuning indicator –Speaker

Functional Description (cont.) Operating modes –Off –Auto tune –Manual tune –Audible reference pitch

Block Diagram

Overall Flowchart Table Look-Up Subroutine Software

Fundamental Determination –Typical Musical Waveform input: Milestones and Critical Problems

Input Conditioning Hardware –Schematic: Milestones and Critical Problems

Peak Detector Circuit –Schematic: Milestones and Critical Problems

Peak Detector Circuit –Critical Problem - Switching Noise: Milestones and Critical Problems

Peak Detector Circuit –Switching Noise Solution - LPF: Milestones and Critical Problems

Peak Detector Circuit –Solution Results: Milestones and Critical Problems

Complete Input Hardware –Response to Vocal Pitch: Milestones and Critical Problems

Complete Input Hardware –New Problem: Milestones and Critical Problems

Frequency Divider –74294 Programmable divide by 2^n Minimum divide of 2^2 –Need 2^1 to tune zero octave Milestones and Critical Problems

Manley Board Difficulties –External Interrupt –Port 1 Priority on Stand-Alone Microcontroller Hardware and User Interface Hardware Milestones and Critical Problems

User Interface –Component Selection 16 vs. 7 Segment LED displays Zero Center Analog Meter –Interface Simplification Pitch and Octave Up/Down Buttons vs. Rotary Switches –GAL for Address Decoding, Display Drive, and Button Debouncing

Future Work Original Design –Automatic Octave Selection –Improve Accuracy –Other Modes (Manual Tune, Reference Pitch) New Ideas –Automatic Gain Control –Improve Resolution

Progress Summary Peak Detector 2^n Frequency Divider GAL Usage Stand alone microcontroller hardware Student Research Exposition Auto Tuning Mode –9 octave range (1-9) –User selected octave Tuning Accuracy –1 cent at A4=440 Hz –5 cents at ends of table range Auto-chromatic Musical Instrument Tuner Craig Janus and Bob Schmanski Advisor: Dr. James Irwin, Jr.