Turing Machine Program Card

Turing Machine turns the Music Thing Modular Workshop Computer into a two-channel random looping sequencer. It produces evolving melodies, repeating CV patterns, and rhythmic pulses that can move gradually between randomness and locked loops.

This Program Card is based on the original Music Thing Modular Turing Machine, launched in 2012. Unlike a conventional step sequencer, you do not enter a specific melody. Instead, you steer a changing sequence until it finds a pattern you want to keep.

• Current firmware documented here: v1.5.3
• Watch a quick Turing Machine card demo on Instagram
• Open the Turing Machine web editor

Quick start

1. Insert the Turing Machine card with the gold connector facing down.
2. Press the small Reset/Load button beside the Program Card slot.
3. Patch CV Out 1 to the Pitch input of the top oscillator.
4. Patch Pulse Out 1 to an envelope, gate input, or another clocked destination.
5. Tap the Z switch down several times to set a tempo.
6. Put the Main knob near 12 o'clock for a changing random sequence.
7. Turn the Main knob clockwise towards 5 o'clock to settle into a repeating loop.
8. Use X to choose the loop length.
9. Use Y to make Channel 2 run slower or faster than Channel 1.

If the pitch output is not in tune, calibrate the Workshop Computer with the Simple MIDI card. See Pitch calibration.

The central idea: random, slipping, or locked

The Main knob controls how much the sequence changes:

Main knob position	Behaviour
Around 12 o'clock	Fully random; the sequence keeps changing
Around 3 or 9 o'clock	Slipping loop; mostly repeats but changes occasionally
Around 5 o'clock	Locked repeating loop
Around 7 o'clock	Double-locked loop, repeating a pattern twice the selected length

Once a sequence changes, you cannot return to its previous state. That irreversibility is an intentional part of playing a Turing Machine.

Every Program Card has a unique serial number, which seeds its random sequence. Different cards therefore behave slightly differently. Starting a card with the Main knob in a locked position should reproduce that card's initial pattern until you randomize it.

Controls

Main — Random / Loop

Moves both channels between continuously changing random sequences, gently slipping loops, and fully locked patterns.

X — Loop Length

Selects a sequence length of:

2, 3, 4, 5, 6, 8, 12, or 16 steps.

The LEDs briefly indicate the selected length.

Y — Diviply

Divides or multiplies the Channel 2 clock relative to Channel 1. This creates slower, faster, and polyrhythmic relationships between the two channels.

CV In 1 is added to the Y-knob setting, so Diviply can be voltage controlled.

Z switch — Presets and tap tempo

• Up: select the first configured preset.
• Middle: select the second configured preset.
• Tap down: set the internal tempo.

The two presets can use different scales, ranges, pulse modes, note lengths, and other settings. Configure them with the Turing Machine web editor.

Inputs

Input	Function
Pulse In 1	Main external clock; replaces tap tempo and drives both channels
Pulse In 2	Independent clock for Channel 2; replaces Diviply clocking
CV In 1	Adds positive or negative CV to the Channel 2 Diviply setting
CV In 2	Experimental chromatic pitch offset applied to both pitch outputs
Audio/CV In 1	Experimental reset; a rising edge returns all sequences to their first step
Audio/CV In 2	Experimental CV preset selection

For Audio/CV In 2, approximately +1 V or more selects the Z-up preset; approximately -1 V or less selects the Z-middle/down preset.

CV In 2 accepts an approximate 0–1 V pitch signal and applies a chromatically quantized offset to both pitch outputs. This input is experimental and is not calibrated.

Outputs

Output	Function
Pulse Out 1	Channel 1 clock or Turing-bit pulse, selected in the editor
Pulse Out 2	Channel 2 clock or Turing-bit pulse, selected in the editor
CV Out 1	Quantized Channel 1 pitch CV
CV Out 2	Quantized Channel 2 pitch CV
Audio/CV Out 1	Channel 1 Turing CV with an editor-configurable range
Audio/CV Out 2	Channel 2 Turing CV with an editor-configurable range

When Pulse In 2 is connected, Channel 2 runs independently and Pulse Out 2 follows Pulse In 2.

Clocking

Tap tempo

With nothing connected to Pulse In 1, tap Z down in time with the music. The card calculates its internal tempo from your taps.

Main external clock

Patch a clock to Pulse In 1 to replace tap tempo. The external signal drives Channel 1 and becomes the source for Channel 2's Diviply clock.

After an incoming clock changes speed, Diviply waits for a second pulse before adopting the new rate. This can create musically useful transitions rather than immediately averaging the change.

Pulse In 1 works into high audio rates. At sufficiently high rates, the card can behave like a random wavetable oscillator.

Independent Channel 2 clock

Patch another clock to Pulse In 2 to bypass Diviply and run Channel 2 independently. In this mode, Pulse Out 2 follows the second external clock.

Configuring the card

The browser editor lets you configure both Z-switch presets.

Launch the Turing Machine editor.

The editor can change:

• Scale or mode
• Octave range, from one to four octaves
• Note length
• Channel 2 loop-length offset
• Pulse mode for Pulse Out 1 and Pulse Out 2
• Audio/CV output ranges

Available note-length behaviours include:

• Blip: approximately 1% of the note duration, with a minimum around 2 ms
• Short variable: controlled by an internal Turing sequence
• Long variable: controlled by another internal Turing sequence

The variable note lengths lock and randomize along with the note sequences.

Each pulse output has two principal modes:

• Clock: emit a pulse on every clock step.
• Turing: emit a pulse only when the relevant Turing Machine bit is 1, similar to the Pulse output on the original hardware Turing Machine.

Connecting the editor

1. Connect the Workshop Computer's front USB-C port to your computer with a data-capable cable.
2. Cycle the Workshop System's power so that the USB connection is detected.
3. Insert and load the Turing Machine card.
4. Open the editor in Google Chrome.
5. Allow the site to access MIDI when the browser asks.

The editor communicates with the card using MIDI SysEx. Chrome is the tested browser; Safari on macOS does not support this editor.

If the editor cannot find the card:

• Confirm that the USB cable carries data, not only power.
• Turn the Workshop System off and on again.
• Refresh the editor after the card has loaded.
• Check that the browser has permission to access MIDI devices.

The older editor should redirect to the current version.

Restoring default settings

You may need to clear stored settings after updating the Program Card:

1. Hold the Z switch down.
2. Tap the Reset/Load button beside the Program Card slot.
3. Keep holding Z until a fast animation appears on the LEDs.
4. Release Z.

This clears the stored configuration and returns the card to its default settings.

Pitch calibration

The Turing Machine reads the precision-output calibration stored by the Simple MIDI card. If CV Out 1 or CV Out 2 does not play the Workshop System oscillators in tune, use Simple MIDI to calibrate the Computer first.

See the complete Workshop System calibration guide.

CV In 2's experimental pitch-offset function is quantized but is not itself calibrated.

Patch ideas

• Patch CV Out 1 and Pulse Out 1 to the top oscillator and an envelope for a self-running melody.
• Patch all four CV outputs to non-pitch inputs - filters, Slopes CV inputs - to create chaotic but rhythmic patterns.
• Send Audio/CV Out 1 to CV In 1 to modulate Diviply with another Turing sequence.
• Use a slow external clock on Pulse In 1 and a faster clock on Pulse In 2 for independent, intersecting patterns.
• Put Main near 3 or 9 o'clock for a loop that changes only occasionally.
• Configure one preset as a narrow melodic scale and the other as a wide, unruly range, then switch between them manually or through Audio/CV In 2.
• Drive Pulse In 1 at audio rate and listen to the Audio/CV outputs as oscillator-like signals.

More information

• Turing Machine card on the Music Thing Modular Program Cards page
• Current Turing Machine web editor
• Quick card demo
• The original Music Thing Modular Turing Machine

For implementation details, version-specific engineering notes, known issues, and testing questions, see TECHNICAL_NOTES.md.