The Turing Machine is a hugely popular module which produces random sequences of configurable length which can be held constant, or allowed to change slowly over time. Think of it like a sample-hold for sequences.
The circuit here is based on the Music Thing Modular Turing Machine with some minor tweaks. The changes I've made are thus:
- Added polarity protection so that a backward power header doesn't fry anything (twin series schotty diodes: BAT54SL),
- Full surface mount design on a single PCB,
- Simpler input power filtering,
- Expanded length choices to include 7, 9, 11, and 13 (in addition to the default 2, 3, 4, 5, 6, 8, 12, and 16).
This module should be a drop-in replacement for the Musing Thing Modular version with the same width and same basic panel layout. I've altered it somewhat to fit with the aesthetic and practices of my DIY build, however the pinouts for expansion modules adhere exactly to the original. This repo inherits the same license as the original Turing Machine: CC-BY-SA
The KiCAD project here uses the library/footprints found in my companion repo.
10hp
Jacks:
- Clock (required input)
- CV for setting "Change" rate
Knobs:
- Change rate
- Sequence length (12 position switch)
- Scale
Write switch for setting the current bit high or low.
Jacks:
- CV output of of sequence
- Whitenoise
- Pulse whenever the current bit is high
LEDs:
- 8x for the current binary representation of the output tone
- 1x for the pulse
- 1x for the clock input
There are part numbers in the BOM for many of the parts (not for basic passives though) at the following vendors:
- Mouser: Needs no introduction. Get your ICs from here (or digikey).
- Tayda Electronics: Good supplier for passive components; audio jacks, and potentiometers. Their audio jacks are slightly smaller than the thonkiconn from thonk.
- Love My Switches: Has really good knobs to go on those potentiometers!
- OSHPark: Fast and (relatively) cheap PCB manufacturer. Prototype run pending.