MIDI Sequencer

miniMO's Sequencer is a MIDI step sequencer with easy step edition and real time tempo and transposition control (see here for more details).


Download from Github


  • Master and Slave Modes
  • Configurable MIDI channel
  • Configurable number of steps
  • Configurable scales
  • Real time Tempo control
  • Real time Transposition with configurable intervals
  • Real time Octave control with configurable number of octaves
  • Real time selection of forward or reverse playback
  • Step Edition Mode with real time note and length control
  • Random sequence generation on start up
  • Automatic Battery check



  • 2: Output - MIDI notes
  • 4: Output (master) / Input (slave) - gate trigger


MASTER (default)

The sequencer sends a trigger every step through I/O 4, also during editing


The sequencer advances a step when it detects a trigger through I/O 4

  • To set the sequencer to Slave Mode, turn the module ON while pressing the button, and release the button after the battery check
    • The LED turns OFF -now the module is waiting for a trigger
  • All regular functions are available in Slave Mode
    • Tempo Control is also available
      • The unit will send MIDI notes at the internal tempo, if it's slowest than the external
      • The internal tempo also determines the note length (very fast internal tempos produce shorter notes)


PLAY (default)

The sequencer plays through all the steps. The LED turns ON and OFF to mark each step

  • Knob: change tempo / transpose pattern
    • when you hop between parameters, miniMO waits until you reach the last value it has currently stored to start effecting changes
  • Single click: go to EDIT mode
    • To edit a step, click the button during the PREVIOUS step
    • The pattern freezes in the step after you click, which becomes ready to edit
  • Double click: change play mode between regular and reverse
  • Click and Hold (hold for about 1s): change knob's function between tempo / transposition control

Each time you turn the module OFF and ON, miniMO plays a new random sequence


The sequencer repeats the current step indefinitely at the tempo set in PLAY mode. The LED stays ON continuously

  • Knob: change note
    • miniMO waits until you reach the note it has currently stored to start effecting changes
  • Single click: go to PLAY mode
  • Double click: change note length between half (staccato), full (legato), and silence, in this order
    • By default, the first note is set to full (to mark the beginning of the pattern), and the other notes are set to half


When you switch the module ON,

  • If the LED blinks once, the battery is OK
  • If the LED blinks fast several times, the battery is running low


This program requires a modified version of the SoftwareSerial library to run. Get it here!

The module's "wait until the knob reaches the last stored value" behavior might be a bit unresponsive at low tempos

In Slave mode, the maximum rate is not as high as in Master Mode