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MIDI Pitch Transposition Unit

 

MIDI Pitch Transposition

 

The MIDI Pitch Transposition unit can be used to shift the pitch of a MIDI note by up to +7 or -7 semitones, on all MIDI channels except Channel 10 ( the drum channel). Also all MIDI Channel commands, Program Change, Control Change, Pitch Bend, Channel Pressure and Polyphonic Key Pressure are passed through unchanged. All MIDI System Realtime messages are filtered out.

 

 

 

 

*Click to Enlarge*

 

MIDI Pitch Transposition

ITEM#: MIDIPITCHTRANS

PRICE:  €45.00


 

  

  

  

 

 

The MIDI Pitch Transposition unit utilizes:

  • An assembled, built and tested Arduino board including a suitable pre-programmed Atmega microcontroller,
  • A 2.1mm power socket, and associated LED, 
  • A MIDI detection LED,
  • A MIDI IN/OUT Board with opto-isolator input,
  • A 4-way DIP switch, which selects the Pitch Transposition, shown in table 1
  • A 150mm wired MIDI 5-pin DIN input socket,
  • A 150mm wired MIDI 5-pin DIN output socket, 
  • The circuit schematic is available,.

 

 

The MIDI Pitch Transposition unit  requires:

  • A 9 Volt battery or equivalent 9 Volt DC external power source, or USB Connector.

 

MIDI IN/OUT Wiring:

 MIDI_IN_OUT_CONNECTIONS.JPG (212235 bytes)

     *Click to Enlarge*

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

 

 

 

 

Operation:

The unit detects the incoming MIDI data and the MIDI Pitch Transposition unit is then used to shift the pitch of a MIDI note by up to +7 or -7 semitones, on all MIDI channels except Channel 10 ( the drum channel).

 

   

    

MIDI Specification: 

 The MIDI Pitch Transposition unit works on all MIDI channels (1-16), except the drum channel 10. So the pitch of all the notes playing are transposed by the same amount. The system will also work with MIDI running status.

 

 

DIP Switch Selections

PITCH CHANGE 
4 3 2 1
on on on on -7
on on on off -6
on  on  off on -5
on on off off -4
on off on on -3
on off on off -2
on off off on -1
on off off off 0
off on on on +7
off on on off +6
off on  off on +5
off on off off +4
off off on on +3
off off on off +2
off off off on +1
off off off off 0

Table 1 Pitch Transposition

 

 

Power Supply:

The  Arduino  can be powered via the USB connection or with an external power supply. The power source is selected automatically. 

 

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector. A low dropout regulator provides improved energy efficiency.

 

The board can operate on an external supply of 7 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.