Open Theremin V3 with MIDI interface control software for Arduino UNO

Based on Arduino UNO Software for the Open.Theremin version 3.0 Copyright (C) 2010-2016 by Urs Gaudenz https://github.com/GaudiLabs/OpenTheremin_V3

Urs makes also a very clear presentation of this MIDI feature on his website (many thanks !): http://www.gaudi.ch/OpenTheremin/index.php?option=com_content&view=article&id=200&Itemid=121

Don't click on the files!

Click on the "clone or download" Button to the right. Then unpack the archive.

Open Source Theremin based on the Arduino Platform

Open.Theremin is an arduino shield to build the legendary music instrument invented by Leon Theremin back in 1920. The theremin is played with two antennas, one to control the pitch and one for volume. The electronic shield with two ports to connect those antennas comprises two heterodyne oscillators to measure the distance of the hand to the antenna when playing the instrument. The resulting signal is fed into the arduino. After linearization and filtering the arduino generates the instruments sound that is then played through a high quality digital analog audio converter on the board. The characteristics of the sound can be determined by a wave table on the arduino.

For more info on the open source project and on availability of ready made shield see:

http://www.gaudi.ch/OpenTheremin/

Installation

1. Open up the Arduino IDE

2. Open the File "Open_Theremin_V3.ino"

3. In "Application.cpp", take care of selecting MIDI mode that correponds to your cituation (put "//" in front off inadequate line - MIDI through serial is selected by default here):

   Serial.begin(115200); // Baudrate for midi to serial. Use a serial to midi router http://projectgus.github.com/hairless-midiserial/

   //Serial.begin(31250); // Baudrate for real midi. Use din connection https://www.arduino.cc/en/Tutorial/Midi or HIDUINO https://github.com/ddiakopoulos/hiduino

   I tested "Hiduino" and "midi to serial" modes, both are OK.

4. Selecting the correct usb port on Tools -> Serial Port

5. Select the correct arduino board from Tools -> Board

6. Upload the code by clicking on the upload button.

Added and removed compare to Open Theremin V3.

Serial communication implemented for program monitoring purpose was removed (Particularly during calibration). If you need to monitor calibration for antenna problem fixing, please use original master branch from https://github.com/GaudiLabs/OpenTheremin_V3.

Serial port is used to send midi messages now.

How does it work ?

PITCH ANTENNA (ROD):

It uses first note detected as hand moves away from from volume loop antenna to generate a NOTEON. Then it can use PITCHBEND (if activated) to reach exact pitch as long as pitch bend range will do. Beyond it can generate a new NOTEON followed by a NOTEOFF for the previous note if legato mode activated. Pitch bend range can be configured (1, 2, 7, 12 or 24 semitones) to align with synth's maximum capabilities.

It can also generate a midi continuous controler change if one is selected.

VOLUME ANTENNA (LOOP):

It generates selected midi continuous controler change, starting NOTEON and ending NOTE OFF (when playing staccato). The trigger volume can be configured so as we have some volume at note attack on percussive sounds.

CALIBRATION:

This device runs normal calibration of antennas after pushing button for 3 seconds as per initial project

SETTINGS:

"Register" Pot becomes "Selected Parameter" pot and have 8 positions. "Timbre" pot become "Parameter's Value" and have variable number a position depending on selected parameter:

1. Register: 4 positions as in original Open Theremin V3
2. Timbre: 8 positions as in original Open Theremin V3
3. Channel: 16 positions (channel 1 to 16)
4. Rod antenna mode: 4 positions (Legato off/Pitch Bend off, Legato off/Pitch Bend on, Legato on/Pitch Bend off, Legato on/Pitch Bend on)
5. Pitch bend range: 5 positions (1, 2, 7, 12, 24 Semitones). For classical glissando and in order to have same note on audio and MIDI, use exactly same pitch bend range on your synth. Maximum setting possible is recomended.
6. Volume trigger: 128 positions (0 to 127)
7. Rod antenna cc: 5 positions (None, 8-Balance, 10-Pan, 16-Ribbon controler, 74-cutoff)
8. Loop antenna cc: 8 positions (1-Modulation, 7-Volume, 11-Expression, 71-Resonnance, 74-Cutoff, 91-Reverb, 93-Chorus, 95-Phaser)

Select a Parameter and move "Parameter's Value" to change corresponding setting.

Manipulation of "Rod antenna cc" and "Loop antenna cc" is not error proof. MIDI newbies should be advised to change their value in MUTE mode.

Default configuration is: Register = Lowest Register, Timbre = 1st Waveform, Channel = MIDI Channel 1, Rod antenna mode = Legato on/Pitch Bend on, Pitch bend range = 2 Semitones, Volume trigger = 0, Rod antenna cc = None, Loop antenna cc = 7-Volume.

MUTE BUTTON:

Sends ALL NOTE OFF on selected channel and stay in mute until it's pushed again.

AUDIO:

Audio processing from antennas to output jack, including volume and pitch pots, LEDs and button functions, is exactly the same as in open theremin V3.

What can I do to get a theremin like glissando?

Activate picth bend and set pitch bend range of the theremin with a high value (12 semitones or 24 semitones). Set pitch bend range of the synth with the same value

If I do not trigger with the volume hand it also seems to trigger a new tone with the pitch antenna. Guess this is how MIDI works.

When legato mode is activated, if you trigger a note (with volume loop) and go in one direction (with pitch antenna) a new note will be triggered at the limit of pitch bend range.

Legato mode is used as a workaround for a limitation of midi (max 24 semitones pitch bend). Maybe some synth can perform pitch bend on more that 2 octaves but none of mine does...

LICENSE

Original project written by Urs Gaudenz, GaudiLabs, 2016 GNU license. This Project inherits this 2016 GNU License.

Check LICENSE file for more information

All text above must be included in any redistribution