Transcript Laser Harp
LASER HARP Team: Peter Crinklaw Qiushi Jiang Edwin Rodriguez WHAT IS A LASER HARP? • A laser harp is an instrument composed of laser “strings” • Notes are mapped to the laser strings and when a laser is blocked, a note is played DEMO • Official website for our Laser Harp • http://www.ualberta.ca/~qsjiang/laserharp.html MOTIVATION • The motivation for this project was to create an instrument which is: • Great for live performances • Easy to play • Encourages engineering in a younger audience CORE FUNCTIONALITY • Internal Synthesizer • The laser harp offers a built in full-range synthesizer • External MIDI output support • Produces MIDI 1.0 compatible signals ADDITIONAL FUNCTIONALITY • Able to change music scale on the fly • Such as Major, Minor, Blues… • Able to shift to any key • So you can jam with your favorite sound tracks. • Simple user interface DESIGN - OVERVIEW • Input and output External MIDI Signal NIOS II Synthesizer Laser harp hardware DESIGN - OVERVIEW DESIGN – LASER DETECTION • 8 photo diodes • Ambient light: 0.2V • Laser: 0.5V • Comparator circuit implemented using op-amp • Threshold voltage: 0.35V • 8 GPIO pins generating interrupt DESIGN – MIDI GENERATOR • Maps lasers to a music scale • Generates a MIDI 1.0 signal • MIDI signal is basically the digital representation of music notation. Image from: http://online-music-score.com/ DESIGN – MIDI GENERATOR • Signal Contains 3 bytes and 2 bits separator around each byte. • 0 Status Byte 1 0 Pitch Byte 1 0 Velocity Byte 1 DESIGN - SYNTHESIZER • The synthesizer’s job is to produce audio signals: DESIGN - SYNTHESIZER • Low frequency signal: • High frequency signal: DESIGN - SYNTHESIZER • Just stores one audio signal DESIGN - SYNTHESIZER • Audio Signal sent to the WM8731 Audio Codec • Codec converts digital audio signal to analog audio signal • Analog signal finally reaches the speakers POTENTIAL IMPROVEMENT • Additional sensor to provide note velocity • Octave shift • Pedal / IR distance sensor • More instruments QUESTIONS