CV2MIDI - Users Manual

Firmware Version 0.21
VMC-2 Hardware Version 1.0

CV2MIDI should be named in fact an2MIDI because it does a generic "analogue to MIDI"-conversion. The software translates incoming voltages, triggers, or gates into various MIDI data.
There are eight so called ports. Each port can do its own type of conversion. The MIDI data sent can be composed from multiple ports.
Most extreme Example:

• port 1 provides the note number,
• port 2 provides the velocity value of this note
• port 3 receives the gate, on which the MIDI note data is sent

Quickstart...

• ...for those, who think they don't need manuals:
  

  	Mode	Buttons	Function
  Normal Mode	Parameter Selection	<- DATA encoder ->	Select the parameter of the actual port
  		ENTER button	Enables parameter edit
  		DATA button	Enables the port selection
  		Press and hold the DATA button Press and Release ENTER Release the DATA button	Changes to system menu
  		Press and hold the DATA button Press and hold ENTER Release DATA button Release ENTER button	Changes to monitoring mode
  	Port Selection	<- DATA encoder ->	Selects the port
  		DATA button	Returns to parameter selection
  	Parameter Edit	<- DATA encoder ->	Select the parameter value
  		ENTER button	Writes the selected value to the memory and returns to normal mode
  	Monitoring Mode	ENTER	Re-calculate the values
  		DATA button	Enables the port selection
  		Press and hold ENTER Press and hold the DATA button Release ENTER Release the DATA button	DATA button Returns to normal Mode
  System Mode	System Menu	<- DATA encoder ->	Select the system function
  		ENTER button	Enables the selected function
  		Press and hold the DATA button Press and Release ENTER Release the DATA button	Returns to normal Mode
  All Modes		Press the DATA button Press ENTER Release the DATA button Press the DATA button Release ENTER Release the DATA button	Resets the program but keeps the custom settings

• Good Luck

Now more details for the patient ones...

Controls and Connectors

The VMC-2 provides eight so called "ports". Each port has one input socket and one trimmer potentiometer for the input level.

The inputs will recognize voltage changes between 0 Volt and +5 Volt. Incoming voltages that are above +5V or any negative voltages are ignored. If you want to handle any voltages above +5 Volt you have to reduce the input signal with the corresponding trimmer. If you want to handle negative voltages you have to achieve a level shift and possibly some attenuation by using an external offset module like for example the Doepfer A-183-2 (https://doepfer.de/a1832.htm). Also the Doepfer A-138a provides a suitable offset option(https://doepfer.de/a138.htm).

To send MIDI data the VMC-2 requires a MIDI input/output module from the VMC-system like the MIDI-ITO, MIDI-ITOs, or MIDI-3IT with MIDI-OOO. Handling and sending MIDI data via the VMC-bus to other modules of the VMC series is possible too.

Operation Modes

CV2MIDI has two operation modes

• In the Normal Mode the CV2MIDI sends MIDI data according to the incoming voltages.
• In the System Mode MIDI data are not sent; generic settings are done instead.

Normal Mode

Select a parameter

In normal mode the display shows in the top line the parameter (in the example "TYPE") and the number of the selected port (in the example "1"). In the bottom line the value of the selected parameter is displayed (in the example "Trigger").

The DATA encoder selects the parameters for the actually selected port. Depending on the basic setting of the port there are different  parameters.

Edit the value of a parameter

To edit the value of a parameter, press the ENTER button. An angle bracket will appear in front of the value

Select the port

Remark: It is not possible to switch the port while you are editing the value of an parameter.

System Mode

To switch between normal mode and system mode(*)

• Press and hold the DATA button
• Press and Release ENTER
• Release the DATA button

The display now will show:

Within System mode you have to select a function using the DATA encoder. The various functions require individual handling. Please see the detailed descriptions below.

if you used the opposite order of pressing and releasing button by mistake, you will switch to the monitoring mode (see below). Please check that section, how to leave the monitoring mode

Available parameters.

Depending on the functionality different parameters can be selected / adjusted. The following table lists the parameters for each functionality

Basically there are three types of action:

• "Trigger" sends one single MIDI command if the incoming voltage crosses a threshold level from below the threshold to above the threshold (this threshold level can be defined in the system settings).
• "Gate" sends one single MIDI command if the incoming voltage crosses a threshold level from below the threshold to above the threshold, and a corresponding MIDI command if the incoming voltage crosses a threshold level from above the threshold to below the threshold level. Example: Note On and Note Off
• "CV" translates the incoming voltage proportionally in data values. If the parameter command is set to "CC" or "Note" then a new MIDI command will be sent for each new value. If the command is set to "value" no MIDI data are sent from this port, but the generated value can be used by some other port 

Trigger with ClockCommand

Trigger with Control Change (CC)

Trigger with Note

Gate with ClockCommand

Gate with Control Change (CC)

Gate with Note

CV with Control Change (CC)

CV with Note

CV with value

How the CV function works - the relation between "range" and "resolution"

Basically, a CV function with Note or CC as a command sends the corresponding command as soon as the input voltage changes. If you set "Range" to 127 and "Offset" to 0, turning the input level produces a glittering glissando of chromatic notes. If you set the "Range" to 13 and the "Offset" to 60, a full turn of the input level trimmer produces a chromatic scale from C3 to C4. This is how it works under theoretically ideal conditions.

In fact, it depends on the "Range" setting whether a change in the input signal should be recognized as a valid value change. At low "Range" settings, small changes in the input voltage can lead to double triggering of the same note, which would lead to new notes at high "Range" settings. For a low "Range" of only one octave, you need a resolution value of 10 or 12, for high "Range" values you need a resolution of "1". If you have a high "Range" setting such as "127" and increase the resolution, the MIDI commands will only be sent on every second change. This results in a whole tone scale for the notes, then a scale of minor thirds, then major thirds and so on. This works like a quantizer, but in quite unconventional scales.

As this can be a little confusing, the display shows a "recommended" value for the resolution in brackets, which is calculated for the current "Range" value. If you select this value, notes or CCs are always triggered to the next note or CC value.

How to adopt the VMC to voltage sources

• To enter the monitoring mode, press and hold the DATA button, press and hold ENTER, release the DATA button, release ENTER.
• In monitoring mode, two numbers are shown on the bottom line of the display. The left number is the lowest output value, the right number is the highest output value, which both have be derived from the incoming voltage since the last press of ENTER. Please note that these values depend on the "Offset" and "Range" settings for the respective port.
• To redo the measurement, briefly press ENTER.
• To return to the normal mode, press and hold ENTER, press and hold the DATA button, release ENTER and release the DATA button.

• Set the "Offset" parameter on the VMC-2 to "0"
• Set the "Range" parameter on the VMC-2 to "127"
• Turn the input level control fully clockwise.
• Set the VMC-2 to monitor mode.
• Now use your sequencer or keyboard to switch back and forth between the highest and lowest voltage.
• Check the maximum output value.
• If the value is below 127, leave the input level potentiometer at the right stop.
• If the value is 127, turn the input level potentiometer slowly to the left while you press ENTER repeatedly until the value starts to fall below 127.
• Check whether the sent lowest voltage triggers the desired lowest output value (press ENTER repeatedly to reread the value).
  • If not, correct the "Offset" value.
  • If the "Offset" is already at zero, but the monitor shows a higher value as minimum, then your incoming voltage does not reach 0 Volt as the lowest voltage.
• Then check whether the highest desired output value is actually sent with the highest voltage.
• If the value sent is too high, reduce the "Range" value
• If the value sent is too low although "Range" is set to "127", then the output voltage of your keyboard or sequencer does not appear to reach 5 volts.

• On the VMC-2 set the input level potentiometer of the corresponding port fully clock wise
• On the VMC-2 set the parameter "Offset" to 0 (zero)
• On the VMC-2 set the parameter "Range" to 127
• Mixer: Connect the LFO and the constant voltage to two inputs of the mixer
  Offset-Modul: connect the LFO to the input of the offset modul.
• Mixer: Turn both inputs of the mixer down,
  Offset-Modul: turn the input down and set the offset to 0 (zero).
• Set the VMC-2 to monitor mode.
• On the Mixer or Offset-Modul turn the input of the LFO fully up
• Check on monitor page of the VMC-2 the highest value. If this value is below 63 then the full sweep of the signal is below 5V. Remember this highest value
• On the Mixer or Offset-Modul turn the input of the LFO fully down
• On the Mixer or Offset-Modul turn the Offset value up;
  • If the highest value created by the LFO was below 63, then set the Offset-amount at the Mixer/Offset-Modul so the VMC-2 now displays the same maximum value
  • If the highest value created by the LFO was above 63, then set the Offset-amount at the Mixer/Offset-Modul to 63 displayed on the VMC-2 monitor
• On the Mixer or Offset-Modul turn the input of the LFO slowly up until the highest MIDI command value reaches 126.
• Check now the lowest value of the MIDI command. If it is above 0 then turn the offset a little bit down and increase the LFOs level a little bit.

System Settings

(This section still is under development in version 0.21)

In the System section the various functions are called up by pressing ENTER. Some functions are then executed automatically, other functions will call up additional menues. It is common to all functions that they will return to the first page of the system settings, where no function is called up until it has been selected with the DATA encoder.

Adjust Potis

This is a procedure to adopt the software to the individual potentiometers and to the limiting diodes in the input. How to proceed:

• Do NOT press ENTER immediately
• Remove all cables from the input sockets
• Turn all eight trimmers fully clock wise
• Now press ENTER

You will see how the program very quickly counts up a number from 0 for each port and then displays the word "GOOD!" for one second. The number should not count much further than 150 or 160. If the count keeps going up, check that the trimmer is really set fully clockwise and repeat the process.

Factory Reset

This will reset the settings of all ports to a factory setting:

MIDI Soft Thru settings

This setting is not made per channel, but for all channels in general

Save settings / Load settings (not implemented yet in Version 0.21)

In theory it's possible to store 3 different settings in the internal EEPROM of the Arduino. Perhaps we will provide this option.

Trigger Level

Note Length factor (not implemented yet in Version 0.21)

Transpose Enable

Transpose Center Note