OSCtoCV Converter for Modular Synthesizer

Overview

• The main purpose of this is to convert OSC (Open Sound Control) message to CV/Gate (method of controlling Analog Synthesizer) by using ** mbed (LPC1768)** and D/A converter.

• The OSCtoCV has 8ch CV out, 4ch Gate out, Sync out and MIDI out and send&receive OSC via an Ethernet.

• With this, you can control modular synth from computer, DAW (plug-in), tablet device, ..etc and this can generate CV with an accurate musical pitch tracking by using calibration data.

• OSCtoCV has MIDI out. For instance you can control MIDI drum machine (volca sample ..etc) with it.

• When combine this with TouchOSC, you can control OSCtoCV sequencer parameters, scale, ..etc graphically, and likewise you can make your own custom interface.

Source & Binaries

• mbed repositorie

• Schematic, TouchOSC template, app, VST Plug-in(currently only supported on OSX)(zip) #04/14/16 update

• Plug-in and Calibrator source code (Github)

Some Demos

• Shift Sequencer

• M185 Sequencer

• F437 Sequencer

• Beats Sequencer & volca sample

Calibration Data

The OSCtoCV using VCO calibration data made with OSCtoCV Calibrator and you can replace default calibration data with an original data.
The calibration data text file consists of float value one per line and the line number corresponds to the MIDI note numbers that is you can easy to make original scale by using calibration data array indexes.

How it works.

Common method of control

Scale

• OSCtoCV can generate adjusted CV to musical scales and you can select that by using OSC message with address pattern /ctrl2 and arguiments are float value.

  1. Linear => 0.0
  2. Chromatic => 0.125
  3. Major => 0.25
  4. Major7 => 0.375
  5. Minor7 => 0.5
  6. Dorian => 0.625
  7. Minor => 0.75
  8. Fifth => 0.875
  9. Whole tone => 1.0

Sequencer Variables

Operating Modes

• OSCtoCV has several operating modes.

• In three CV sequencer modes, you can choose Euclidean beat generator or step beats sequencer which you want to output OSCtoCV MIDI out.

• Calibration Mode

  • OSCtoCV outputs CV corresponds with MIDI note number 69 (A-4) from all CV out, you can check and adjust the VCO frequency (A-4 440Hz) by using VCO’s tune knob.

• OSCtoCV Mode

  • This mode is simply converting OSC (Open Sound Control) message to CV/Gate, and you can control CV glide parameter by using Glide pot.

  • Note: When Glide pot is zero, you can control glide value by using OSC message with address pattern /ctrl4 and argument float 0.0f ~ 1.0f.

• Shift Sequencer Mode

  • In this mode, OSCtoCV runs step CV sequencer by using combined with TouchOSC and outputs are shifted (like a shift-register) with gate ON/Off timing.

• M185 Sequencer Mode

  • In this mode, OSCtoCV runs M185 type sequencer by using combined with TouchOSC and also outputs are shifted.

• F473 Sequencer Mode

  • In this mode, OSCtoCV runs 1 ~ 4ch shift sequencer + 5 ~ 8ch M185 type sequencer by using combined with TouchOSC.

• Euclidean Sequencer Mode

  • In this mode, OSCtoCV runs Euclidean gate sequencer by using combined with TouchOSC and you can trigger MIDI drum machine by using MIDI out.

• Random Generator Mode

  • In this mode, OSCtoCV runs 8ch random CV generator.

• Stepped LFO Mode

  • In this mode, OSCtoCV runs stepped LFO generator.