draft: false
Name: Tesserae
short-description: "Tesserae — Variable-voice (2-8) arpeggiated chord generator with 5 patterns, 10 scales, tap tempo, CV/audio transpose inputs, and dual CV + audio pitch outputs. Inspired by Laurie Spiegel's Music Mouse and Patchwork."
Language: C++ (Pico SDK + ComputerCard)
Creator: Joep Vermaat
contact:
  email: joep@joep-i.nl
  website: https://codeberg.org/johantv/
Version: 1.0
Status: Released
License: MIT
date-created: 2026-05-08
date-updated: 2026-05-08
Repository: https://codeberg.org/johantv/Tesserae

tags:
  - arpeggiator
  - harmonic
  - cv
  - utility

summary: |
  Variable-voice arpeggiated harmonic generator with 5 patterns and 10 scales. X sets melody
  position, Y sets chord spacing, and Main changes by Z mode (pattern select, root note, or held
  scale/voice selection). Supports tap tempo, external clock/reset, and dual transpose inputs.

panel:
  inputs:
    - id: AudioIn1
      name: Pitch Transpose
      type: audio
      description: Semitone transpose for arpeggiated voice outputs (1V/oct)
    - id: AudioIn2
      name: Root Transpose
      type: audio
      description: Semitone transpose for root/chord framework (1V/oct)
    - id: CVIn1
      name: Melody Position CV
      type: cv
      description: Offsets knob X melody position
    - id: CVIn2
      name: Chord Spacing CV
      type: cv
      description: Offsets knob Y spacing
    - id: PulseIn1
      name: External Clock
      type: pulse
      description: Advances one arpeggio step per rising edge
    - id: PulseIn2
      name: Reset
      type: pulse
      description: Restarts arpeggio at step 0
  outputs:
    - id: CVOut1
      name: Arpeggiated Note
      type: cv
      description: Current arpeggiated note, calibrated 1V/oct
    - id: CVOut2
      name: Root Note
      type: cv
      description: Root/base melody pitch, calibrated 1V/oct
    - id: AudioOut1
      name: Arpeggiated Note Audio
      type: audio
      description: Mirrors CVOut1 on audio DAC (approximate 1V/oct)
    - id: AudioOut2
      name: Previous Note Audio
      type: audio
      description: Holds previous arpeggio note on audio DAC (approximate 1V/oct)
    - id: PulseOut1
      name: Gate
      type: pulse
      description: High while current arpeggio note is active
    - id: PulseOut2
      name: Trigger
      type: pulse
      description: Short pulse at each arpeggio step start

controls:
  knobs:
    - when: { z: up }
      main:
        name: Arpeggio Pattern
        description: Selects one of five arp patterns
      x:
        name: Melody Position
        description: Selects base note in current scale across three octaves
      y:
        name: Chord Spacing
        description: Scale-degree spacing between voices
    - when: { z: middle }
      main:
        name: Root Note
        description: Sets root note across C1-C7
      x:
        name: Melody Position
      y:
        name: Chord Spacing
    - when: { z: down }
      main:
        name: Tap Tempo
        description: Two taps within two seconds set internal BPM
    - when: { z: down }
      main:
        name: Scale Select
        description: Selects one of ten scales
      y:
        name: Voice Count
        description: Sets 2-8 voices
  leds:
    - display: list
      items:
        - id: LED0
          name: Voice Index 0-3
          description: LEDs 0-3 show current voice index modulo 4
        - id: LED1
          name: Voice Index 0-3
        - id: LED2
          name: Voice Index 0-3
        - id: LED3
          name: Voice Index 0-3
        - id: LED4
          name: Scale/Voice Select Active
          description: Lit while Z down hold scale/voice mode is active
        - id: LED5
          name: External Clock Present
          description: Lit when PulseIn1 external clock is connected