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MIDI 128 Note Keyswitch Encoder with LCD Menu

 

MIDI Organ Encoder with LCD Menu

 

 

This MIDI organ Keyswitch Encoder is used to convert a Wurlizter Omni 3500 dual keyboard with pedalboard to MIDI. The organ has a 4 x 12 diode matrix for the upper and lower manuals and a 4 x 4 diode matrix for the pedalboard.

  

The switches are normally momentary action, push to make, single pole single throw (SPST), switches used to produce the equivalent MIDI note-on/note-off data commands on any MIDI Channel (1 to 16), selectable via the LCD Menu Selection. The encoded switches are wired via IN4148 diodes. There are also inputs for various foot-switches and foot-pedal inputs available.

  

The unit can work with different size keyboards. Any unrequired/unused keyswitches can be left unconnected.  Note ONLY the switches required need to be wired.

 

This unit can be connected to new keyboards or it can be used with an older non-MIDI keyboard by using magnetic/reed switches to isolate the old and new scanning circuits. 

 

This unit can work in standard MIDI mode and via the USB connection. It defaults to standard MIDI Baud rate of 31250. By replacing the original firmware on Mega8u2/16U2, the Arduino will act as USB-MIDI device (Standard Midi Class), you don’t need to install additional device drivers on Windows, MaxOSX, and Linux, as the firmware acts as a device of Standard Midi Class. It will automatically install on the system as an Audio USB Device.

 

 

  

16x8keys_LCD.JPG (43949 bytes)

 

MIDI Organ Encoder with LCD Menu

ITEM#: MIDIORGKEYLCD

PRICE:  €75.00


 

 

 

 

The MIDI Organ Encoder with LCD Menu Unit consists of:

  • The MIDI channels, Program Change, Velocity and Transpose are selected via the switches on the LCD menu,
  • An assembled Arduino MEGA board with pre-programmed micontroller,
  • A 2.1mm power socket, and associated LED, 
  • USB power or external power choice,
  • A MIDI 5-pin DIN output socket,
  • A 16x2 LCD display and Menu selection switches.

 

 

The MIDI MIDI Organ Encoder with LCD Menu unit requires:

  • a 9v battery or equivalent DC power source or USB connection,
  • Suitable key-switches or magnetic reed switches and associated IN4148 diodes
  • Suitable switches/foot-switches (3 off)
  • Suitable potentiometers/foot-pedals (1 off)

 

Circuit Schematics:

 

  

  

  

 

Menu Selection & Specification: :

The Menu Selection button cycles through the Menus:

  • Upper Manual: MIDI Channel: 1 to 16
  • Lower Manual: MIDI Channel: 1 to 16
  • Bass pedaboardll: MIDI Channel: 1 to 16
  • Program Change: 0 to 127
  • Velocity: max 127
  • Transpose: +/- 2 Octaves in semitone steps

 For each Selection the 'UP' and 'DOWN'  buttons can set the MIDI Channels, Program Change, Velocity and Transpose values. Also the MIDI Channels, Program Change and Velocity values are stored in EEPROM so they are remembered each time the unit is powered up or reset.

 


 

 

MIDI OUT Wiring:

 midi_out_LCD.JPG (56402 bytes)

     *Click to Enlarge*

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

 


 

MIDI Organ Encoder with LCD Menu Wiring:

The switches are organized in a 4 x 12 diode matrix for the upper and lower manuals and a 4 x 4 diode matrix for the pedalboard. Note if less switches are required, then ONLY the switches required need to be wired. 

 


 

Jack Socket Wiring:

Switch foot pedals usually use a MONO jack socket. Variable potentiometer pedals can use a  MONO or STEREO jack socket.

 

So either a standard 6.3mm (¼in) style switched 2-pole MONO jack socket with 2-poles switched upon insertion of the jack plug, with switched normally closed contacts available in 2-pole or  a standard 6.3mm (¼in) style switched 3-pole STEREO jack socket with 3-poles switched upon insertion of the jack plug are required.

 


 

MIDI Pedal Switch Functions:

Digital Input Pin  

MIDI Pedal Functions

D48  Sustain
D50  Sostenuto
D52  Portamento

Table 1

 

Sustain Pedal: 

The sustain pedal is also known as the Damper Pedal. When operated it sends out a controller value of CC64. When the pedal is pressed ON the unit outputs a value of 127, when released OFF the unit outputs a value of 0. Tone-generators without the 'half-damper' implemented will interpret a value between 0 and 63 as OFF and a value of 64 to 127 as ON.

   

Sostenuto Pedal: 

The sostenuto pedal is a type of selective sustain pedal found on acoustic grand-pianos. Pressing down the pedal, sending controller value CC66 with a value of 127, while holding notes on the keyboard will cause these notes to be sustained after you release them. Any notes played after pressing the pedal will not sustain. When the pedal is released it sends out controller value CC66 with a value of 0.

    

Portamento (Glide):

When the portmento switch is pressed, sending out controller value CC65 with a value of 127 (to 64) then Portamento is on. When the portmento switch is released, sending out controller value CC65 with a value of 0 (to 63) then portamento is off.

  


 

MIDI Pedal Controller Functions:

Analog Input Pin  

MIDI Pedal Functions

A15  Volume

Table 2

   

NOTE: It is important to connect any unused Analog Input Pins to prevent spurious noise producing a MIDI Output. (MIDI volume is at a maximum if +5 Volt is applied to the Volume input pin and a Minimum if 0 Volt is applied to Volume input pin. 

 

MIDI Volume:

MIDI Volume is used to control the volume level for one MIDI channel. Uses MIDI Control Change numbers CC7 (coarse) and CC39 (fine). Most devices ignore the Fine adjust (CC39) for Volume, and just implement Coarse adjust (CC7) because 14-bit resolution isn't needed for this. In this case, maximum is 127 and off is 0. If using a MultiTimbral device, then each Part can have its own volume.

  


 

  

Power Supply:

The  Arduino MEGA 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.