Digital Electronics Lab 8 (Step Sequencer)

Code:

int ledPin[4] = {29, 30, 31, 32};
int buttonPin[4] = {33, 34, 35, 36};
bool switchedOn[4] = {false, false, false, false};
bool buttonState[4] = {LOW, LOW, LOW, LOW};
bool lastButtonState[4] = {LOW, LOW, LOW, LOW};
int tempo = 0; 
int mappedPotValTempo = 0;
int currentStep = 0;
unsigned long lastStepTime = 0;

void setup() {
  for (int i = 0; i < 4; i++) {      //use a for loop to set all LEDs and button pins
    pinMode(ledPin[i], OUTPUT);
    pinMode(buttonPin[i], INPUT);
  }
}

void loop() {
  checkButtons();
  updateLeds();
  stepForwards();
  
}

void checkButtons() {
  for (int i = 0; i < 4; i++) { 
    lastButtonState[i] = buttonState[i];
    buttonState[i] = digitalRead(buttonPin[i]);
    if(lastButtonState[i] == LOW && buttonState[i] == HIGH) {
      flipbuttonstate(i);
      delay(5);
    } else if(lastButtonState[i] == HIGH && buttonState[i] == LOW) {
      delay(5);
    }
  }
}

void flipbuttonstate(int i) { //for organization
  if(switchedOn[i]== true){
        switchedOn[i]= false;
      }
      else if(switchedOn[i]== false){
        switchedOn[i]= true;
      }
}

void updateLeds() {
  for (int i = 0; i < 4; i++) {   
    if(switchedOn[i] == true or i == currentStep) { //so that it blinks if the button isn't pushed and stays lit if it is
      digitalWrite(ledPin[i], HIGH);
    } else {
      digitalWrite(ledPin[i], LOW);
    }
}}

void stepForwards() {  
  tempo = analogRead(A19);
  if (millis() >= lastStepTime + tempo) {           //tell Teensy when to start running the function with millis()
    
    lastStepTime = millis();
    usbMIDI.sendNoteOff(40, 0, 1);
    currentStep++;                                  //increase counter
    
    if (currentStep == 4) {
      currentStep = 0;                              //reset counter
    }
    
    if (switchedOn[currentStep] == true) {
      usbMIDI.sendNoteOn(40, 127, 1);
    }
  }
}

Video: