The Random Looping Sequencer is a circuit that produces clocked randomly changing control voltages. These can also be locked into loops that repeat every 8, 16 or 32 steps.
This is an open hardware project – all the project files (Eagle CAD projects, Gerbers PCB files, a Mouser BOM and Illustrator/PDF front panel designs) are available on this page, covered by a Creative Commons Attribution Share-a-like license, which allows for commercial use.
This is a relatively advanced DIY project, and I’m not able to provide support. I am not selling PCBs, kits or finished modules, but hopefully all the information you’d need to get your own is here: Getting the parts to build a random sequencer. Update: You may be able to buy full kits from thonk.co.uk
The obligatory video demo:
A few audio demos:
As a sequencer:
One random sequencer controlling a Dixie oscillator clocking a second random sequencer acting as a wavetable oscillator (phew!):
Documentation and build documents
(All CC licensed)
The latest version is v2.1, which fixes the capacitor polarity issue in v2. V2 schematics and documents are below.
random sequencer documentation v2.1
- This PDF file contains the schematic, block diagram, how the circuit works and how to build the PCB.
random sequencer v2.1 schematic
- Large png image of the rather scruffy schematic. It’s all there. If you want to examine the schematic in detail, the Eagle version might be easier to navigate.
Random Sequencer Panels – pdf + illustrator
Random sequencer panels – pdf only
- These contain the files used to create two different styles of panel for the sequencer.
Background and research documents
- A collection of web-sourced background material about the history of random voltage sources and shift register sequencers, including: pages from Allen Strange and Hal Chamberlin’s books, interview transcript with Don Buchla, documentation for modules from Grant Richter and Dieter Doepfer and an essay on process music by Steve Reich.
Random Sequencer Datasheet Collection
- PDF datasheets of many of the ICs and other components used
random sequencer documentation_v2
- Important: Please read this addendum before building using the v2 instructions above.
Random Sequencer v2 Part Placement image
Hey Tom,
First of all thanks a lot for your Turing sequencer project. I’ve built two for myself and love them to bits!
Now I’m considering building a run of 10 or 20 to sell at a profit.
I understand this is licensed under creative commons.
Nevertheless, I’d find it just fair to have you participate with the proceeds if this pans out.
Do you have a specific amount per module in mind?
I’m also willing to donate to NGOs or muffwiggler if you prefer this.
Are there any other things to take into account besides crediting you as the creator of the project?
Thanks again, greetings from Berlin
Michael
Hi, you’re completely within your rights to sell these at a profit, so long as you make it clear that you are the manufacturer, and not me.
Tom
Thanks for this.Great Module !
Keep up the good work.
vogelmenach
This could get addicting. The random loops sound very interesting. For someone writing songs this technology could be a starting point for melodies. A good composer could take some of these random patterns, work with them a create a song.
This looks amazing! Does it work on +/-15V as well?