draft: false
Name: Uncertainty
short-description: Buchla 266-style noise/FRV/QRV, plus a wavefolder and pulse alternator.
summary: |
  A tribute to the Buchla 266 Source of Uncertainty — three noise colours
  (flat, low-biased, high-biased), a Fluctuating Random Voltage that glides
  continuously between new targets, and a Quantized Random Voltage that
  jumps to a new value on each trigger — sharing the card with an
  antialiased wavefolder (ported from Chris Johnson's Utility Pair) and a
  Pulse In 1 alternator that duplicates each incoming pulse across Pulse
  Out 1 and Pulse Out 2 in turn. Z switch Up turns Main/X/Y into bipolar
  attenuverters for the wavefolder's CV In 1, FRV's output, and QRV's
  output respectively, with pot-pickup so returning to normal never snaps
  a value to wherever the knob was left.
Language: C++ (Pico SDK + ComputerCard)
Creator: Matt Allison
Version: "1.0.0"
Status: Released
License: MIT
date-created: 2026-09-03
date-updated: 2026-09-04

tags:
  - source-of-uncertainty
  - random
  - noise
  - wavefolder
  - utility

panel:
  inputs:
    - id: AudioIn1
      name: Fold In
      description: Wavefolder input
    - id: CVIn1
      name: Fold Drive Mod
      description: Bipolar, scaled by Main's attenuverter role (Z up) then added directly onto the Main knob's drive amount, unclamped — enough negative CV (or a CCW attenuverter setting) inverts the signal before folding
    - id: CVIn2
      name: FRV Rate Mod
      description: Bipolar modulation of the FRV rate, +-6V, added on top of knob X
    - id: PulseIn1
      name: QRV Trigger / Alternator In
      description: Rising edge latches a new Quantized Random Voltage value. The same input is also duplicated straight through to Pulse Out 1/2, alternating which one gets each pulse.
  outputs:
    - id: AudioOut1
      name: Fold Out
      description: Wavefolder output
    - id: AudioOut2
      name: Noise Out
      description: Current noise colour (flat / low-biased / high-biased)
    - id: CVOut1
      name: FRV Out
      description: Fluctuating Random Voltage, free-running 0 to +6V before X's attenuverter role (Z up) is applied — CCW of centre there makes it swing negative instead
    - id: CVOut2
      name: QRV Out
      description: Quantized Random Voltage, 0 to +6V span set by knob Y's primary role, before Y's attenuverter role (Z up) is applied — CCW of centre there makes it swing negative instead
    - id: PulseOut1
      name: Alternator Out A
      description: A literal copy of Pulse In 1's timing, routed here on every other incoming pulse (alternates with Pulse Out 2)
    - id: PulseOut2
      name: Alternator Out B
      description: A literal copy of Pulse In 1's timing, routed here on the pulses Pulse Out 1 doesn't get

controls:
  switch:
    up:
      name: Attenuverter Mode
      description: Main/X/Y each switch to a bipolar attenuverter for the section they already control (wavefolder CV In 1 / FRV output / QRV output) instead of their normal role. 12 o'clock mutes; CCW inverts and scales towards full negative; CW scales towards the original full-positive value. Each knob's two roles are pot-pickup guarded, so switching in or out of Up never jumps a value — it stays frozen until the knob is moved back to where that role was left.
    tap:
      name: Cycle Noise Colour
      description: Briefly press and release Down to cycle the noise source between flat, low-biased (pink, -3dB/oct) and high-biased (blue, +3dB/oct). LEDs 0/2/4 hold the current mode.

  knobs:
    - main:
        name: Fold Drive
        description: Gain into the wavefolder, combined with CV In 1 — low settings pass the signal clean, higher settings drive it into folding
      x:
        name: FRV Rate
        description: Exponential taper across three decades, 0.05Hz to 50Hz, modulated by CV In 2
      y:
        name: QRV Range
        description: Sets the maximum span of each new Quantized Random Voltage draw, 0 to +6V
    - when: { z: up }
      main:
        name: Fold CV In 1 Attenuverter
        description: Bipolar attenuverter for CV In 1's contribution to the wavefolder's drive. 12 o'clock = CV In 1 has no effect (same as unpatched).
      x:
        name: FRV Output Attenuverter
        description: Bipolar attenuverter for FRV's output voltage. 12 o'clock mutes CV Out 1; CCW makes FRV swing negative, CW keeps it swinging positive as before.
      y:
        name: QRV Output Attenuverter
        description: Bipolar attenuverter for QRV's output voltage. 12 o'clock mutes CV Out 2; CCW makes QRV swing negative, CW keeps it swinging positive as before.

  leds:
    - display: list
      items:
        - id: "0"
          name: "Noise: Flat"
          description: Lit when the noise source is in flat (white) mode
        - id: "1"
          name: FRV Level
          description: Brightness follows the magnitude of the current FRV output regardless of sign (0V off, brightest at +-6V) — a single LED can't show polarity, so it shows how far from 0V, not which direction
        - id: "2"
          name: "Noise: Low-biased"
          description: Lit when the noise source is in low-biased (pink) mode
        - id: "3"
          name: QRV Level
          description: Brightness follows the magnitude of the current QRV output regardless of sign (0V off, brightest at +-6V) — a single LED can't show polarity, so it shows how far from 0V, not which direction
        - id: "4"
          name: "Noise: High-biased"
          description: Lit when the noise source is in high-biased (blue) mode
        - id: "5"
          name: Alternator Trigger
          description: Lit for the duration of every pulse on Pulse In 1, regardless of which of Pulse Out 1/2 it's currently being routed to

uf2:
  - path: UF2/uncertainty.uf2
    name: Uncertainty firmware