Project

Modern music synthesizers are be expensive and complicated. Furthermore, music theory can be intimidating to learn when you don’t have the right equipment to practice the fundamentals.

TheorySynth offers a solution in the form of an affordable, simple, and easy-to-use synthesizer. Featuring both a 2-octave keyboard and 21-key chord board, TheorySynth is the perfect playground for mastering the fundamentals of modern music theory.

System Overview

Methods

• Implemented using FreeRTOS on STM32 development boards
  • One microcontroller for each module allows for greater octave range without conflict
  • FreeRTOS provides efficient handling of various user input simultaneously
• Voltage waveforms created via varying indexing rates through various waveform look-up tables
  • Timer interrupt indexes through the tables with changing increments
  • Voltage levels are then generated through an on-board DAC
  • Common amplifiers ensure the waveforms produce audible music
• Chord generation via combining three varying voltage levels
• Simple designs lead to simple solutions
• Complex designs lead to complex problems

Conclusion

Results:

• Keyboard module successfully generates on-pitch tones
• Chord module successfully generates triads within a user-chosen key signature
• Octave and Waveform controls successfully modify generated tones
• Chord progressions and melodies may be played simultaneously

Next Steps:

• Implement analog ADSR volume envelope controls
• Software optimizations to allow for multi-key press
• Hardware upgrades to increase the project’s capable octave range
• Implement MIDI protocol over USB to enable digital music transcription