Sixty Four Pixels – ARPIE – Full DIY Kit

From: £67.25 (Excl. VAT)

Fully Featured Standalone Arpeggiator Kit

This kit has a white panel

CV TAB Expander

Pre-Assembled CV Expansion Board

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ARPIE is a compact, highly-functional, MIDI arpeggiator that comes as a DIY kit.

If you are looking at this, it is likely you already know what an arpeggiator is, but if not here is a quick description… An arpeggiator is a device which takes chords (maybe played on a keyboard) and converts them into rapid sequences of notes, which can then be played through a MIDI-compatible synthesizer (either hardware or software). Arpeggiation is a very common technique in electronica and chiptune music and is an excellent creative technique. You should note that ARPIE does not make any sound by itself, but rather outputs MIDI note information which can play a synth, sampler, software synth or other compatible sound module.

ARPIE’s Hardware and firmware are open source, and the firmware is based on Arduino, making it easily hackable.

User Guide | Build Guide | BOM & Schematics


  • Arpeggiate Up/Down/Up-Down/Randomised/Manual or play all notes in polyphonic gated chord mode
  • Mutate and extend the arpeggio with inserted notes: None/Lowest note/Highest note/meander 3 steps forward 1 step back/4 steps forward 2 steps back
  • Force arpeggiated notes to a musical scale: 7 musical modes/11 root notes/selectable out-of-scale note handling
  • Extend input chord over 1-4 octaves
  • Control playback rate: 1 beat per step thru to 1/32 beat per step, including dotted and triplet time options
  • Control note length and MIDI velocity
  • Transpose up or down by 1-3 octaves, by -3 thru +12 semitones from front panel, or by any pitch via MIDI input note
  • 1-16 step play/rest pattern (selected steps played or muted) with randomisation option
  • The transpose sequencer feature automates up to 16 bars of transposition. Combined with the force to scale option this is awesome for finding new chord progressions and creating entire songs.
  • Manual chord entry (note toggle) mode. Experiment with chords and access ARPIE’s full potential without any keyboard attached!
  • Per-step Accent, Full Gate, Tied Gate, Octave Up/Down, Fourth interval down, Play Through (Play notes together polyphonically) with randomisation options
  • With optional CV TAB daughter board sold separately supports CV/Gate out with per-step pitch glide and 1V/oct and Hz/V pitch scaling. CV TAB also adds ability to save and recall up to 16 patches – snapshots of the ARPIE chord and settings
  • Selectable MIDI transmit/receive channel + OMNI receive mode + MIDI thru + MIDI panic + MIDI “Channel Mode” message filter
  • Ability to send MIDI LOCAL ON/LOCAL OFF message to use ARPIE as an outboard arp for a keyboard synth (as long as the synth supports LOCAL OFF switching via MIDI CC#122)
  • Configurable Accent velocity level with special support for Volca FM velocity controller
  • Internal MIDI clock with BPM select and tap tempo/send master clock to clock input
  • Clock input from main MIDI input or separate dedicated MIDI clock input socket
  • Manual stop/start/continue play options when clocked to external MIDI clock
  • MIDI lock mode ignores note input and thru input to output in MIDI lock mode
  • 6 pin “Hack Header” expansion port breaks out power and four GPIO lines.Standard firmware allows three standard potentiometers to be wired up to hack header and configured to control MIDI CC’s, Mod, Bend, BPM, Velocity etc
  • Three standard 5-pin DIN sockets for MIDI IN, MIDI OUT, SYNC IN
  • Receive, Transmit, Beat Clock and Chord Hold LEDs on control surface, firmware diagnostic/power LEDs on main board, reset button.
  • Integral 9V PP3 battery holder and 9V DC socket (2.1mm barrel) which works with either polarity plug.
  • Small size (98mm x 87mm x 35mm approx dimensions) and light weight (approx 125g without battery)

Soldering is required to complete this kit. Surface-mounts will be pre-soldered so you will only need to fit the through-hole components.


The CV Tab is an add-on for the ARPIE kit that plugs into the “hack header” expansion socket on the ARPIE main board. It comes fully assembled and tested and adds the following functions to your ARPIE…

  • A 1V/octave pitch control voltage (CV) output with 0-8V range and pitch glide between “tied” notes
  • A note gate/trigger output at ~10V
  • A clock output at ~10V, switchable between 16th note and 8th note steps. Optionally use the output as an accent trigger instead.
  • 8kB of EEPROM, enough to store 16 “snapshots” of ARPIE state (even when powered off) for instant patch recall
  • LED indicators that blink with gate and clock signals

The 10V clock/gate pulses are generated by an on-board charge pump circuit, even when running ARPIE from a 9V battery or 9V DC supply. 10V is the voltage level output by equipment such as Beatstep Pro and SQ-1 and can be used with Eurorack modular gear or vintage synths.


Additional information

CV TAB Expander

Weight 0.0164 kg

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