[This units comes with the new firmware that syncs to MIDI clock, rock solid]

OPERA ROTAS is a mutant, generative drum machine. It's built around a Yamaha OPL2 FM audio chip, a close cousin of the one used in the Sega Genesis / Megadrive consoles.

At the core, it has a real Yamaha OPL2 audio chip and live sounds bonkers, brutal. It's all body and weight while being crystal clear and punchy. The videos don't do aural justice but it serves to get an idea.

There will be nicer audio and video demos coming soon.

The project will go open source at some point while I retain the hardware manufacturing rights. If you get one PCB or kit you can ask for the source code to tweak it if you will.

This unit comes fully assembled, with the OPL2 board installed and ready to use.

You can watch it in action here:

https://www.youtube.com/watch?v=NrZZiTpK3f0

Richard Devide demoing it:

https://www.instagram.com/p/CLp2tOrgvjg/

Manual, schematics and interactive BOM available in the github https://github.com/spherical-sound-society/OPERA_ROTAS

You can watch additional videos and gather info in this thread: https://www.muffwiggler.com/forum/viewtopic.php?f=17&t=233199

The keyboard shortcuts are:

REC - start/stop. The ">" sign in the upper left appears when the OR sequencer is running.
AUTO - engage AUTO mode. In AUTO mode, the active channel changes every step. When you move a knob, the corresponding parameter of the active channel is affected.
AUTO + Pressing the keys from 1 to 8 load the sound presets
LOCK - engage LOCK mode. Pressing the keys from 1-8 the corresponding channel toggles from locked to unlocked.
EDIT - engage EDIT mode. Press the keys 1-16 to edit the active pattern. The pattern is shown on the leds.
CHAN - engage CLEAR mode. Pressing the keys from 1-8 clears the corresponding channel.
RND - engage RANDOM mode. Pressing the keys from 1-8 randomize the corresponding channel. Randomization is made with the Euclidean algorithm.
SAVE - engage MUTE mode. Pressing the keys from 1-8 the corresponding channel toggles from muted to unmuted.
SHIFT + AUTO - toggles slave MIDI mode.
SHIFT + LOCK - locks all channels.
SHITH + CHAN - clears all channels.
SHIFT + RND - Select generative mode. In GEN1 mode every 16 step the gates of one pattern and one sound parameters is randomized. In GEN2 mode gates are unchanged; every step one sound parameter is randomized. Bpm selection is disabled.
SHIFT + SAVE - mutes all channels.