Control Voltage (CV)/Gate to MIDI 

 

The CV/Gate to MIDI unit is capable of converting the output control/gate voltages from a monophonic synthesiser  to a MIDI  note-on/note-off data commands. The unit works with linear CV out Volts/Oct where 0 volt is set to C1 and 4 volt is set to C5. However different MIDI note octave ranges can be pre-programmed, if required.  Each semi-tone is equal to (1/12 = 0.08333 Volt). The gate output voltage from the synthesiser can be between 5 to 15 volts when a note is ON and 0 volt when the note is OFF.

 

 

	CONTROL Voltage to MIDI ITEM#: CV2MIDI PRICE:  €35.00

The Control Voltage (CV)/Gate to MIDI unit utilizes:

• A Miduino kit including a suitable pre-programmed Atmega168,
• A 2.1mm power socket, and associated LED, 
• A MIDI 5-pin DIN output socket,
• 8 off 0.1" pin-terminal outputs,
• The circuit schematic is available,
• The transmit MIDI channel (1-16) can be selected by a 4-way DIP switch. 
• The velocity byte is preset to half of the maximum value.
•  The CV to MIDI unit is monophonic

 

 

 

The Control Voltage (CV)/Gate to MIDI unit  also requires:

• A 9v battery or equivalent DC power source,
• A Gate trigger LED, and transistor driver,
• A variable 10k linear potentiometer for scale tuning,
• A variable 10k linear potentiometer for volume adjustment (optional), plus a 5.1 Volt Zener diode and associated 1k series resistor (optional)

 

 

Circuit Schematic:

A circuit schematic of the Miduino shows the Input/Output connections. The Miduino is designed to connect to external breadboards or matrix boards on a 0.1" grid.

    

Assembly:

The kit includes all parts necessary, the assembly is straightforward and well documented. This design does not include a USB chip, it is designed to use a FTDI USB 232-TTL cable to program the microcontroller.  However since the cable plugs directly into the Miduino, you can use one cable for multiple Miduinos.

   

MIDI Wiring:

The MIDI  OUT connector uses a  5-Pin 180 degree DIN sockets. Note that the MIDI IN/OUT wiring is polarised and the correct pins should be used.

 

Download:

Open the  source code file and copy and paste it into the Arduino programme and save it as a .PDE file.

   

 

 

 

 

 

Tuning to a MIDI octave range scale:

When the Control Voltage (CV) is applied to the CV of the MIDI unit, the potentiometer can be adjusted to give a MIDI C7(96) note out when the CV is 4 volts. This tunes the MIDI unit to the scale shown in Table 1 and the rest of the ranges are  tuned. 

 

 

So the CV potentiometer needs to be adjusted to obtain 1.89 Volts out when 4 Volts CV is applied.

 

The MIDI Note Number to Pitch/Frequency is available and

the MIDI Note Numbers for Different Octaves table is available also.

 

The unit can be used with the Moog Music Etherwave Theremin.