Arduino Midi Keyboard

Arduino Midi Keyboard

#include <Wire.h> //include the library called Wire.h
#include <Adafruit_Trellis.h> //include the library called Adafruit_Trellis.h

#define LED     13 //define LED as a constant interval at 13

Adafruit_Trellis trellis; //create an instance of Adafruit_Trellis and call it trellis

const int CHANNEL = 1; //the interval CHANNEL will always equal 1

unsigned long prevReadTime = 0L; //create an unsigned long called prevReadTime
int autoFilter = 0; //create an interval called autoFilter
int reverb = 0; //create an interval called reverb
int delayPot = 0; //create an interval called delayPot
int vinyl = 0; //create an interval called vinyl

int autoFilterChannel = 1; //create an interval called autoFilterChannel at channel 1
int reverbChannel = 2; //create an interval called reverbChannel at channel 2
int delayPotChannel = 3; //create an interval called delayPotChannel at channel 3
int vinylChannel = 4; //create an interval called vinylChannel at channel 4

int autoFilterChangeVal = 0; //create an interval called autoFilterChangeVal
int reverbChangeVal = 0; //create an interval called reverbChangeVal
int delayPotChangeVal = 0; //create an interval called delayPotChangeVal
int vinylChangeVal = 0; //create an interval called called vinylChangeVal

int lastautoFilterChangeVal = 0; //create an interval called lastautoFilterChangeVal
int lastreverbChangeVal = 0; //create an interval called lastreverbChangeVal
int lastdelayPotChangeVal = 0; //create an interval called lastdelayPotChangeVal
int lastvinylChangeVal = 0; //create an interval called lastvinylChangeVal

int note[] = {
  60, 61, 62, 63,
  56, 57, 58, 59,
  52, 53, 54, 55,
  48, 49, 50, 51
}; //assigns the midi notes that will be played by the keypad

void setup() {
  pinMode(LED, OUTPUT); // LED is set to output
  trellis.begin(0x70); //begin using the trellis
  trellis.clear(); //clear the trellis
  trellis.writeDisplay(); //write to and display the trellis
 
 
}

void loop() {
  unsigned long t = millis(); //create an unsigned long called 't' and set it equal to millis
  if((t - prevReadTime) >= 20L) { //if t minus the prevReadTime is less than or equal to 20L (20 milliseconds)
    if(trellis.readSwitches()) { //look at the trellis readSwitches
      
      for(int i=0; i<16; i++) { //for every interval called 'i' where 'i' is less than 16, add 1
        if(trellis.justPressed(i)) { //if 'i' has just been pressed on trellis
          usbMIDI.sendNoteOn(note[i], 127, CHANNEL); //send the midi value of 'i' at a velocity of 127 to CHANNEL
         
          trellis.setLED(i); //turn on trellis LED at 'i'
        } else if(trellis.justReleased(i)) { //if the trellis button has just been released
          usbMIDI.sendNoteOff(note[i], 0, CHANNEL); //send the midi value of 'i' at a velocity of 0 to CHANNEL
          trellis.clrLED(i); //clear the trellis LED at 'i'
        }
      }
      trellis.writeDisplay(); //write to and display the trellis
    }
    lastvinylChangeVal = vinylChangeVal; //set lastvinylChangeVal equal to vinylChangeVal
    vinyl = analogRead(0); //vinyl's values are taken from analog out 0 (potentiometer 1)
    vinylChangeVal = vinyl/8; //vinylChangeVal is set to vinyl divided by 8
    if(vinylChangeVal != lastvinylChangeVal) { //i vinylChangeVal does not equal lastvinylChangeVal
      usbMIDI.sendControlChange(15, vinylChangeVal, vinylChannel); //send a control change at control 15 at a value equal to vinylChangeVal at the vinylChannel
    }    
    lastdelayPotChangeVal = delayPotChangeVal; //set lastdelayPotChangeVal equal to delayPotChangeVal
    delayPot = analogRead(1); //delayPot's values are taken from analog out 1 (potentiometer 2)
    delayPotChangeVal = delayPot/8; //delayPotChangeVal is set to delayPot divided by 8
    if(delayPotChangeVal != lastdelayPotChangeVal) { //if delayPotChangeVal does not equal lastdelayPotChangeVal
      usbMIDI.sendControlChange(14, delayPotChangeVal, delayPotChannel); //send a control change at control 14 at a value equal to delayPotChangeVal at the delayPotChannel
    }
    lastreverbChangeVal = reverbChangeVal; //set lastreverbChangeVal equal to reverbChangeVal
    reverb = analogRead(2); //reverb's values are taken from analog out 2 (potentiometer 3)
    reverbChangeVal = reverb/8; //reverbChangeVal is set to reverb divided by 8
    if(reverbChangeVal != lastreverbChangeVal) { //if reverbChangeCal does not equal lastreverbChangeVal
      usbMIDI.sendControlChange(13, reverbChangeVal, reverbChannel); //send a control change at control 13 at a value equal to reverbChangeVal at the reverbChannel
    }
    lastautoFilterChangeVal = autoFilterChangeVal; //set lastautoFilterChangeVal equal to autoFilterChangeVal
    autoFilter = analogRead(3); //autoFilter's values are taken from analog out 3 (potentiometer 4)
    autoFilterChangeVal = autoFilter/8; //autoFilterChangeVal is set to autoFilter divided by 8
    if(autoFilterChangeVal != lastautoFilterChangeVal) { //if autoFilterChangeVal does not equal lastautoFilterChangeVal
      usbMIDI.sendControlChange(12, autoFilterChangeVal, autoFilterChannel); //send a control change at control 12 at a value equal to autoFilterChangeVal at the autoFilterChannel
    }
    
    
    prevReadTime = t; //prevReadTime is set to 1
    
  }
  while(usbMIDI.read()); //so long as it is reading MIDI, the loop will continue
}

This is a self created midi controller. Simply put this device has 16 buttons that send different MIDI notes to any electronic instrument that reads MIDI. I mainly plan on using it with my Digital Audio Workstation as a makeshift MIDI keyboard, making it easier to play melodies and record certain patterns. In addition to sending MIDI notes, it also has 4 potentiometers that can be mapped to various effects. I currently have the potentiometers set to a vinyl hiss, reverb, delay, and filter.

In terms of the code itself, it is fairly straightforward. I needed to include a new library to make sure everything works. This is due to the fact that I am using a new piece of equipment called an Adafruit Trellis. This is an open source backlight keypad driver that can easily be used by many different devices. In addition to the Trellis, I also have 4 potentiometers that can be programmed to control different effects. At the moment the effects I am using are a filter, a delay, some reverb, and vinyl noise. In the loop of the code I have the teensy constantly checking to see if a button has been pressed. If a button is pressed, its LED will light up and it will send a MIDI note to the Digital Audio Workstation (DAW) at full velocity. If a button is not pressed the LED will not be on, and send a signal to the DAW at a velocity of 0.

Each of the potentiometers is set to a certain channel and analog pin. Thus allowing each effect to be have separate controls and values.

Above is my code, commented for better understanding.

Here is a video of my project in action! (The hissing noise you hear during part of the video is intentional, it is one of the effects, the vinyl hiss.)