How to add indicator lights to button sketch I would like to add leds to each button switch in the first code, The first code sends midi messages to a DAW I would like it to also turn on a led as an indicator light. The switch needs to turn the light on if off and off if on. The second code is an example that does this, it works well with one button. I would like to have the 3 buttons on pins 0, 1, 2 and the leds on pins 3, 4, and 5.


#include &lt;Bounce.h&gt;

const int channel = 1;
Bounce button0 = Bounce(0, 5);
Bounce button1 = Bounce(1, 5);  
Bounce button2 = Bounce(2, 5);  

void setup() {
  pinMode(0, INPUT_PULLUP);
  pinMode(1, INPUT_PULLUP);
  pinMode(2, INPUT_PULLUP);
}
void loop() {
  button0.update();
  button1.update();
  button2.update();

  if (button0.fallingEdge()) {
    usbMIDI.sendNoteOn(60, 99, channel);  // 60 = C4 
  }
  if (button1.fallingEdge()) {
    usbMIDI.sendNoteOn(61, 99, channel);  // 61 = C#4
  }
  if (button2.fallingEdge()) {
    usbMIDI.sendNoteOn(62, 99, channel);  // 62 = D4
  }

  if (button0.risingEdge()) {
    usbMIDI.sendNoteOff(60, 0, channel);// 60 = C4
  }
  if (button1.risingEdge()) {
    usbMIDI.sendNoteOff(61, 0, channel);  // 61 = C#4
  }
  if (button2.risingEdge()) {
    usbMIDI.sendNoteOff(62, 0, channel);  // 62 = D4
  }
  while (usbMIDI.read()) {
  }
}


Second sketch:

/*********************
Simple toggle switch
Created by: P.Agiakatsikas
*********************/

int button = 0;
int led = 13;
int status = false;

void setup(){
  pinMode(led, OUTPUT);
  pinMode(button, INPUT_PULLUP); // set the internal pull up resistor, unpressed button is HIGH
}

void loop(){
//a) if the button is not pressed the false status is reversed by !status and the LED turns on
//b) if the button is pressed the true status is reveresed by !status and the LED turns off

if (digitalRead(button) == true) {
  status = !status;
  digitalWrite(led, status);
} while(digitalRead(button) == true);
  delay(50); // keeps a small delay
}
I'd suggest creating an array of MIDI button structs. For each entry you'd have a button object, an LED pin, and a BOOL to track the state of thate button. 

Write a function that loops through the array of structs, checks the state of each one, and does the work to play/stop the notes and toggle the LED states based on the state of each button.