ECE 492 - Computer Engineering Design Project Laser Harp Qiushi Jiang, Edwin Rodriguez, Peter Crinklaw 2015 What is it? It’s a harp with lasers for strings. Block the lasers to play music. Synthesizer The synthesizer’s job is to take commands such as “Play F Sharp” from the MIDI Generator, and output an audio signal (as seen below). Since it can’t store an audio signal for every possible note it can play, it instead samples from a single audio signal at a particular rate corresponding to the pitch of the note. The faster the rate, the higher the pitch. The audio output is sent to the built-in line-out port which can be connected to standard 1/8” audio jack. Features Generates sound using a full-range synthesizer The laser harp has a MIDI output that can be connected to other synthesizers Supports multiple music scales Allows for key transpose Components DE2 x1 : The brain of the laser harp Laser diode x 8 : The laser “strings” Photo diode x 8 : Laser sensor MIDI Output x 1 : External MIDI interface MIDI Generator Software running on the DE2 board detects when a laser is blocked. It determines which laser is triggered and generates a MIDI signal according to the music scale inside the software driver. It sends this signal to two components: our own synthesizer, and the external MIDI output port. A MIDI signal only specifies the pitch of the note, not how it should sound. So external synthesizers plugged into the harp’s MIDI port can interpret the MIDI signal however they want, emulating any kind of instrument. Sine wave audio signal For colour ideas, University Visual Identity Guidelines can be found here: http://www.toolkit.ualberta.ca/VisualIdentityGuidelines.aspx Laser Harp in action MIDI Signal, saying “start playing C4” System Overview Department of Electrical & Computer Engineering