//Allocate the buttons to the digi IOs on the board, pins 2-7
#define BUTTON1 2
#define BUTTON2 3
#define BUTTON3 4
#define BUTTON4 5
#define BUTTON5 6
#define BUTTON6 7
#define BUTTON7 8
//Connect the LEDs to the digi IOs on the board, pins 8-13
//Use the AO as a “shift” key to double
// the number of usable pitches/button
#define SHIFT_KEY A0
//For now, all midi commands are on channel 1
#define CMD_1 0x90
#define CMD_2 0x90
#define CMD_3 0x90
#define CMD_4 0x90
#define CMD_5 0x90
#define CMD_6 0x90
#define CMD_7 0x90
//With medium velocity
#define VEL_1 0x45
#define VEL_2 0x45
#define VEL_3 0x45
#define VEL_4 0x45
#define VEL_5 0x45
#define VEL_6 0x45
#define VEL_7 0x45
//Define the pitches, so we don’t have to keep looking
// up the hex / midi chart
#define PITCH_1 0x3F //D#
#define PITCH_2 0x40 //E
#define PITCH_3 0x41 //F
#define PITCH_4 0x3E //D
#define PITCH_5 0x3D //C#
#define PITCH_6 0x3C //Middle C (C4)
#define PITCH_7 0x45 //A
#define PITCH_8 0x46 //A#
#define PITCH_9 0x47 //B
#define PITCH_10 0x44 //G#
#define PITCH_11 0x43 //G
#define PITCH_12 0x42 //F#

boolean changeState1 = false;
boolean changeState2 = false;
boolean changeState3 = false;
boolean changeState4 = false;
boolean changeState5 = false;
boolean changeState6 = false;
boolean changeState7 = false;
boolean currentState1 = false;
boolean currentState2 = false;
boolean currentState3 = false;
boolean currentState4 = false;
boolean currentState5 = false;
boolean currentState6 = false;
boolean currentState7 = false;
void setup()
{
//Set up the digi IOs as inputs for the buttons
pinMode(BUTTON1, INPUT);
pinMode(BUTTON2, INPUT);
pinMode(BUTTON3, INPUT);
pinMode(BUTTON4, INPUT);
pinMode(BUTTON5, INPUT);
pinMode(BUTTON6, INPUT);
pinMode(BUTTON7, INPUT);
//Set up the digi IOs as outputs for the LEDs
//Set the analog 0 pin as a digi input (no digi IOs left)
pinMode(SHIFT_KEY, INPUT);
// Set MIDI baud rate:
Serial.begin(31250);
}
void loop()
{
//Read all of the buttons, then store into state bool vars
if(digitalRead(BUTTON1) == HIGH) {currentState1 = true;}
else {currentState1 = false;}
if(digitalRead(BUTTON2) == HIGH) {currentState2 = true;}
else {currentState2 = false;}
if(digitalRead(BUTTON3) == HIGH) {currentState3 = true;}
else {currentState3 = false;}
if(digitalRead(BUTTON4) == HIGH) {currentState4 = true;}
else {currentState4 = false;}
if(digitalRead(BUTTON5) == HIGH) {currentState5 = true;}
else {currentState5 = false;}
if(digitalRead(BUTTON6) == HIGH) {currentState6 = true;}
else {currentState6 = false;}
if(digitalRead(BUTTON7) == HIGH) {currentState7 = true;}
else {currentState7 = false;}
//Flush the serial buffer
Serial.flush();
//If the button is pressed
if(currentState1 == true) {
//set the led pin state to on
//If this is the first reading after pressing
if(currentState1 != changeState1){
//send command to start corresponding note
writeNote(CMD_1, PITCH_1, VEL_1);
}
}
//If the button is not pressed
else{
//set the led pin state to off
//if this is the first reading after releasing
if(currentState1 != changeState1){
//send the command to stop corresponding note
stopNote(CMD_1, PITCH_1);
}
}
//Repeats for each button/LED/pitch
if(currentState2 == true) {
if(currentState2 != changeState2) {
writeNote(CMD_2, PITCH_2, VEL_2);
}
}
else{
if(currentState2 != changeState2){
stopNote(CMD_2, PITCH_2);
}
}
if(currentState3 == true) {
if(currentState3 != changeState3) {
writeNote(CMD_3, PITCH_3, VEL_3);
}
}
else{
digitalWrite(10, LOW);
if(currentState3 != changeState3){
stopNote(CMD_3, PITCH_3);
}
}

if(currentState4 == true) {
if(currentState4 != changeState4) {
writeNote(CMD_4, PITCH_4, VEL_4);
}
}
else{
if(currentState4 != changeState4){
stopNote(CMD_4, PITCH_4);
}
}
if(currentState5 == true) {
if(currentState5 != changeState5) {
writeNote(CMD_5, PITCH_5, VEL_5);
}
}
else{
if(currentState5 != changeState5){
stopNote(CMD_5, PITCH_5);
}
}
if(currentState6 == true) {
if(currentState6 != changeState6) {
writeNote(CMD_6, PITCH_6, VEL_6);
}
}
else{
if(currentState6 != changeState6){
stopNote(CMD_6, PITCH_6);
}
}
//Keep a record of the previous state, so we can monitor
//button state changes
changeState1 = currentState1;
changeState2 = currentState2;
changeState3 = currentState3;
changeState4 = currentState4;
changeState5 = currentState5;
changeState6 = currentState6;
changeState7 = currentState7;
}
void writeNote(byte command, byte pitch, byte velocity)
{
//Check if our “Shift” key has been pressed
if(digitalRead(SHIFT_KEY) == HIGH)
{
//Play the pitch in the higher section of the octive
Serial.write(command);
Serial.write(pitch+6);
Serial.write(velocity);
}
else
{
//otherwise play the pitch from the lower section
// of the octave
Serial.write(command);
Serial.write(pitch);
Serial.write(velocity);
}
}
void stopNote(byte command, byte pitch)
{
//No way to know (without keeping track of which pitch was
// played for each button) which pitch to turn off,
//So switch them both off
Serial.write(command);
Serial.write(pitch);
Serial.write(0x00);
Serial.write(command);
Serial.write(pitch+6);
Serial.write(0x00);
}