miniMidiOut

A "fast" midi input to audio output synthesizer with 5 popular waveforms.

Messurement on Pi1 (it is not realy realtime): delay between key press and audio out is 68ms

Usage

You can use (and build) the command line interface (CLI) miniMidiOut on many Linux systems. It does not use a realtime linux-kernel.

An alternative way via Release Files:

• use my Pi1 sd-card content (just a single FAT32 partition is needed)
• use my sd-card image for the eeepc 4G 701 (32bit Pentium, BIOS boot)

With these files/images the system boots a minimal Linux and autostarts miniMidiOut.

1. plugin sd-card
2. plugin MIDI USB keyboard
3. if the MIDI USB keyboard has its own power button: power on!
4. optional: plugin an USB alphanumeric keyboard
5. plugin your headphones to the analog audio
   • pi1: Attention! There is a 4th connection for analog video in the 3.5mm hole :-S
6. power on the Pi1 (or eeepc)
7. wait 16 seconds until 3 tones comes up
8. enjoy classic synthesizer sounds from the 80th !
9. power off the Pi1 (or eeepc)

Features (alphanumeric keyboard)

• press 1 for sinus
• press 2 for saw
• press 3 for square
• press 4 for triangle
• press 5 for noise
• press 0 for sustain

Change fading out the tone (release):

• press 6 for default
• press 7 for a long fade out
• press 8 for no fade out
• press 9 toggles automatic fade out on/off

Change octave:

• press - to set down
• press . to set up

Feature (MIDI keyboard)

• velocity
• pitch bend
• sustain pedal

Switch through the waveforms saw, square, triangle, noise and sinus:

• no sound should be played
• you press the sustain pedal 3 times in 1.5 seconds

Listen to the Audio File

Bugs

On pi1: hotplug (out) the midi keyboard gives a "urb status -32". If you add dwc_otg.speed=1 to the cmdline.txt, it is a fix, but a USB keyboad/numpad will not work.

Details

See this file for more details to build and use miniMidiOut.