dwt98/dr55sync

DR-55 MIDI sync sketch

dr55sync

This project is creating DR-55 MIDI sync board.

BOSS DR-55, Dr. Rhythm, is a programable rhythm machine manuafactured by Roland in 1979. This projects brings MIDI conenectibity to DR-55. This project includes schematics and sketch for Arduino.

Watch demo movie at YouTube

Features

MIDI clock slave sync

DR-55 sync to the MIDI clock from external rhythm machine or sequencer.

Manual play by MIDI

You can play DR-55 manualy from external keyboard or sequencer by MIDI note message. Hi-hat supports variation of open/close/pedal.

Velocity controls Accent

When the velocity value is larger than threshold, accent signal turn on. Threshold value is defined in source code.

Omni Mode Switch

Receive MIDI channel is 10 in default. While the switch sets on, every midi channel is recognized. Receive channel is specified in the source code.

MIDI Implementation

Receive Messages

Channel Messages

Note Message     9x nn vv    (Hex)
  x … midi channel     
      1-16 : When the Omni switch is on
      10   : When the Omni switch is off 
  nn … note number 
      48 = BD
      50, 52 = SD
      51 = RS
      54 = Close HH
      56 = Pedal HH
      58 = Open HH
  vv …velocity
      0 : no sound
      1 - 89 : sound without accent
      90 - 127 : sound with accent
      Threshold is specified in source code.

System Real Time Messages

MIDI Clock        F8  (Hex)
Start             FA  (Hex)
Stop              FC  (Hex)

Hardware

• Using Arduino Pro Mini compatible board (5V 16MHz)

• Power is provided from DR-55.

• The board is connected to DR-55 with 10 core flat cable. Board side of the cable is connector. DR-55 side of cable should be soldered to the DR-55 main board directory. No additional parts or special modification is required in DR-55 side. Please refer Connection Guide in the repository for detail.

• Switch 1 of the DIP SW is a program switch of Arduino. Switch 2 - 4 can be used any setting.

Sketch

Library

The sketch uses Metro library as timers.

PCB Version

Configuration of PCB version is place at the top of the sketch. It assign the io pins. If you use PCB provided from my project, define the appropriate version.

Soldering point on DR-55

Please refer this document.

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