Sustain pedal to MIDI: Using Arduino with MIDI shield.

sustain_pedal.pde

#include <MIDI.h>
// http://playground.arduino.cc/Main/MIDILibrary

// MIDI shield configuration
#define KNOB1  0
#define KNOB2  1
#define BUTTON1  2
#define BUTTON2  3
#define BUTTON3  4
#define STAT1  7  // Status LED
#define STAT2  6

/// I will connect my pedal to analog in 2
#define PEDAL1  2

#define LED 13   		// LED pin on Arduino board


int pedal1val;
int pedal1temp;

void setup() {
    pinMode(STAT1,OUTPUT);
    pinMode(STAT2,OUTPUT);

    pinMode(BUTTON1,INPUT);
    pinMode(BUTTON2,INPUT);
    pinMode(BUTTON3,INPUT);

    for(int i = 0;i < 10;i++) // flash MIDI Sheild LED's on startup
    {
        digitalWrite(STAT1,HIGH);
        digitalWrite(STAT2,LOW);
        delay(30);
        digitalWrite(STAT1,LOW);
        digitalWrite(STAT2,HIGH);
        delay(30);
    }
      digitalWrite(STAT1,HIGH);
      digitalWrite(STAT2,HIGH);

      // Read the initial value of the pedal.
      pedal1val = pedal1read();

      pinMode(LED, OUTPUT);
      MIDI.begin();
}

void loop() {
    /***** SUSTAIN PEDAL *****/
    if(values_are_different(pedal1val, pedal1read())){
        pedal1val = pedal1read();
        MIDI.sendControlChange(64, pedal1val, 1); // Sustain, channel 1
    }
}

int pedal1read() {
    /*return 127 - analogRead(PEDAL1)/8;  // convert value to value 127 - 0*/
    pedal1temp = 127 - (analogRead(PEDAL1) - 82) / 6;  // Fine tuning for my pedal.
    if     (pedal1temp > 127){pedal1temp = 127;}
    else if(pedal1temp < 0)  {pedal1temp = 0;  }
    return pedal1temp;
}

bool values_are_different(int val1, int val2){
    // The easiest way:
    // if(val1 != val2){return true;}
    // else            {return false;}

    // A bit complicated way (trying not to send too many MIDI messages):
    val1 = val1 - val2;
    if(abs(val1) > 5){return true;}  // abs(val1 - val2) is not supported.
    else             {return false;} // see http://arduino.cc/en/Reference/Abs
}

Note:

• l.59
  • There is a built-in function map to accomplish the aim of this line.
• ll.60, 61
  • There is a built-in function constrain to accomplish the aim of these lines.