Features of the Midifighter v1
20091230: post created by Fatlimey
20110510: edited to reflect the current firmware
- The Midifighter is a Class Compliant USB device, so it can plug and play to produce MIDI over USB on Mac, PC and Linux without additional divers needed.
- High performance key scanning, with keys read at 1000hz giving 1ms response to keydowns and 10ms response to keyups (use to the 10-entry debounce buffer). We send the MIDI events to the host as fast as we capture them.
- Bootup menu system sets allows you to alter system settings, which are written to persistent storage and reused at every subsequent reboot. Hold down the top-left key (nearest the USB socket) while powering up to enter Menu Mode. See the Menu System HOWTO post for more.
MIDI Implementation
- The keyboard generates the 16 notes from C2 to D#3 (assuming the standard numbering that "Middle C" = C4, note 60), to line up with the default window of an Ableton Live 8 drum map.
Code:
C3 C#3 D3 D#3
G#2 A2 A#2 B2
E2 F2 F#2 G2
C2 C#2 D2 D#2
or as MIDI note numbers:
Code:
48 49 50 51
44 45 46 47
40 41 42 43
36 37 38 39
The base note of this group is selectable through the menu system allowing the 16 note window to be placed anywhere in the MIDI map.
- The Midifighter generates NoteOn (0x90) and NoteOff (0x80) events to signify a note finishing instead of using a zero velocity NoteOn event.
- MIDI notes have a selectable velocity, which defaults to 127 (0x7f). The velocity is also used for the NoteOff events.
- MIDI notes are generated on a single channel, which defaults to MIDI channel 3 (0x2)
- Sending MIDI events out to the Midifighter on the same channel and note numbers as the keys controls the LEDs. NoteOn lights the LED, NoteOff turns it off. By default pressing a key also lights the LED on that key, but for total control over your LEDs this feature can be turned off using the menus system.
Open Source Resources
- The Midifighter is an open source hardware project. All schematics, firmware, source code and other support documentation are openly available and licensed under Creative Commons (hardware) and GPL (firmware).
- Source code and documentation is available at http://sourceforge.net/projects/midifighter
- Programming potential: program memory is only 35% full, plenty of space to add new features!
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