Midi Drum Controller using one Paper Sensor

gistfile1.c

#include <stdarg.h>
#include <MIDI.h>

// http://www.phys.unsw.edu.au/jw/notes.html <- for MIDI_NOTE
// Range : 40 - 1015
#define RLOW 40
#define RHIGH 1015
#define MIDI_CHANNEL 1
#define MIDI_NOTE 48 // C3
int range = RHIGH - RLOW;

boolean state = false;

// http://playground.arduino.cc/Main/Printf
void p(char *fmt, ... ){
        char tmp[128]; // resulting string limited to 128 chars
        va_list args;
        va_start (args, fmt );
        vsnprintf(tmp, 128, fmt, args);
        va_end (args);
        Serial.print(tmp);
}

void setup() {
  // Initialize MIDI serial
  // Serial will be 31250 and MIDI channel will be 1
  MIDI.begin(MIDI_CHANNEL);
}
 
void loop() {
  int capVal = analogRead(A0);

  if ( (state == false) && (capVal <= 1015) ) {
    if (capVal <= 40) {
      int velocity = 127;
      //p("Hit with velicity: %i (%i)\n", velocity, capVal);
      MIDI.sendNoteOn(MIDI_NOTE, velocity, MIDI_CHANNEL);
      state = true;
    } else {
      int velocity = ((float)(1015 - capVal)/range)*127;
      //p("Hit with velicity: %i (%i)\n", velocity, capVal);
      MIDI.sendNoteOn(MIDI_NOTE, velocity, MIDI_CHANNEL);
      state = true;
    }
  } else if ((capVal > 1015) && (state == true)) {
    //p("Button released (%i)\n\n", capVal);
    MIDI.sendNoteOff(MIDI_NOTE, 0, MIDI_CHANNEL);
    state = false;
  } else {
    // nothing
  }
}