Cycler

C Library to create a cool Arduino tool to use with the Elektron Model: Cycles

It adds some different modes to turn you Model: Cycles into a polyphonic FM synthesizer. And more...

This is written with the Elektron Model: Cycles in mind, but basically it will work with any device that handles 6 different midi channels (or multiple devices, be creative!)

Modes

1. 6-Voice polyphony
2. 3/3 Voice polyphony
3. 3/1 Voice polyphony
4. 4-Voice polyphony
5. 4/1 Voice polyphony
6. Dual note
7. Dual note, 2 voice polyphony
8. Dual note, 3 voice polyphony
9. Triple note
10. Triple note, 2 voice polyphony
11. Berserk mode

6 Voice polyphony

This mode will re-route incoming midi signals on channel 1 to channel 1-6 depending on:

• Which channel is free
• If more than 1 channel is free: which one has been free the longest (to mess as little as possible with long decay tails).
• If all channels are occupied: sacrifice the channel that currently is playing with the lowest velocity.

Usage

Make use of the standard Arduino Midi library and place the Cycler code in-between:

#include <cycler.h>
#include <MIDI.h>

MIDI_CREATE_DEFAULT_INSTANCE();

// Tested on an Arduino Nano
void handleNoteOn(byte inChannel, byte inNote, byte inVelocity)
{
    // Register our note with Cycler.
    // Cycler will give us the next free channel, that we can use to pass the information through:
    byte channel = cycler_note_on(inNote, inVelocity);
    MIDI.sendNoteOn(inNote, inVelocity, channel);
}

void handleNoteOff(byte inChannel, byte inNote, byte inVelocity)
{
    // If it's a note off, we need to inform cycler that there is a note off.
    // Cycler will return the channel that was assigned, so we can pass it through:
    byte channel = cycler_note_off(inNote);
    MIDI.sendNoteOff(inNote, inVelocity, channel);
}

void setup()
{
    // Register note handlers
    MIDI.setHandleNoteOn(handleNoteOn);
    MIDI.setHandleNoteOff(handleNoteOff);
    // Launch MIDI, listening to channel 1.
    MIDI.begin(1); 
}

void loop()
{
    if (MIDI.read()) {
        switch(MIDI.getType()) {
            case midi::Clock:       
                // If it is a Clock tick, we need to inform Cycler that there has been a clock tick.
                cycler_tick();
                break;
        }
    }
}

Schematic

Basically you just need to add a Midi Input/Output (or Through) interface to your Arduino and you're good to go.

TODO: Insert schematic:

3/3 Voice polyphony

This is the same as the 6-Voice polyphony, only with the keybed divided on the center note (C5 by default). Everything below that note is (polyphonicly) divided over channel 1 to 3, everything from that note and higher is divided over channel 4 to 6.

3/1 Voice polyphony

This is the same as 3/3 voice polyphony, with the only difference that everything above the center note is polyphonic (this will play in channel 4). As with 4 voice polyphony, channel 5 and 6 are unused, so you can use those to create a pattern to accompany you.

4 Voice polyphony

This is the same as the 6-Voice polyphony, only then with 4 channels (1 to 4). Channel 5 and 6 are never used, so you can use these two channels to create a pattern like you would do normally on the Model: Cycles (but then with 2 tracks instead of 6). You will be amazed how creative you can get with 2 tracks and trig locks.

4/1 Voice polyphony

This is the same as 3/1 voice polyphony, with the only difference that you have 4 channels below the center note, and 1 note above the center note (this will play in channel 5). Channel 6 is unused, so you can use that to create a funky pattern to accompany you.

Dual note

This mode plays the input of channel 1 on channel 1 and 2 simultaniously. So it is monophonic, but the sound is doubled. This allows you to mix 2 machines together to create unique new sounds. Please note that this mode actually does not adds very much complexity to the Cycler code, but needs to be handle in your Arduino Sketch. See the ModeButton example on how this is handled.

Dual note, 2 Voice polyphony

The same as Dual note, but then with 2 voice polyphony. Output channel 1 & 2 will be duplicated on channel 3 & 4.

Dual note, 3 Voice polyphony

The same as Dual note, but then with 3 voice polyphony. Output channel 1, 2 & 3 will be duplicated on channel 4, 5 & 6.

Triple note

The same as dual note, but then with one note extra. So the input on channel 1 will be duplicated on channel 2 and 3.

Triple note, 2 voice polyphony

The same as triple note, but with 2 voice polyphony. So the input on channel 1 & 2 will be duplicated on channel 3, 4, 5 & 6. (1-3-5, 2-4-6)

Berserk mode

Why not? Each note triggers all 6 channels simultaniously.

Ideas / Todo's

6 pots / 1 button to switch modes (LED's for modes)

• Let the clock through on channel 1 (or all channels?)
• Delay / poly combo
• Drunk delay (1/1, 2/2, 3/3)
  • Habit-like (with different delay times, random notes, shifting, chaos, CC messages)
    • Randomize with volume, pan, pitch, decay, color, shape, sweep, contour, delay?, reverb?, punch, LFO stuff
• Attack slope (2 times, LH & RH)
• Slopes for other CC controls (color, contour, shape, sweep)
  • CC 7 = volume (for attack slope)
  • CC 10 = pan
  • CC 65 = pitch
  • CC 80 = decay
  • CC 16 = color
  • CC 17 = shape
  • CC 18 = sweep
  • CC 19 = contour
  • CC 12 = delay
  • CC 13 = reverb
  • CC 66 = punch
  • CC 102 = LFO speed
  • CC 103 = Multiplier
  • CC 104 = Fade In/Out
  • CC 105 = Destination
  • CC 106 = Waveform
  • CC 107 = Start Phase
  • CC 108 = Reset
  • CC 109 = Depth

Contributing

If you want to contribute, feel free to fork and create a pull request.

Testing

To be honest, this is my first real C project, so I don't have experience with default C unit-test frameworks. I do however have a test target with some test code that validates certain stuff. You can test the code by running make test. If you want to add extra tests, just edit the test.c file.

License

See the LICENSE file.