Digital Electronics Lab 9 (Multi-Channel Step Sequencer)

Video:

Code:

int ledPin[4] = {29, 30, 31, 32};
int channelLeds[3] = {18, 17, 16};
int buttonPin[5] = {33, 34, 35, 36, 27};
int tempo = 0; 
int mappedPotValTempo = 0;
int currentStep = 0;
bool buttonState[5] = {LOW, LOW, LOW, LOW, LOW};
bool lastButtonState[5] = {LOW, LOW, LOW, LOW, LOW};
bool switchedOn[3][4] = { //this formatting was a challenge.
  {LOW, LOW, LOW, LOW},
  {LOW, LOW, LOW, LOW},
  {LOW, LOW, LOW, LOW},
};
int activeChannel = 0;
int noteVals[3] = {40, 42, 44};
unsigned long lastStepTime = 0;

void setup() {
  for (int i = 0; i < 5; i++) {      //Sets I/O for all LEDs and button pins
    pinMode(buttonPin[i], INPUT);
  }
  for (int i = 0; i < 4; i++) {      
    pinMode(ledPin[i], OUTPUT);
  }
  for (int i = 0; i < 3; i++) {
    pinMode(channelLeds[i], OUTPUT);
  }
}

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

void changeChannels() { 
  digitalWrite(channelLeds[activeChannel], LOW);

  lastButtonState[4] = buttonState[4];
  buttonState[4] = digitalRead(buttonPin[4]);
  
  if(lastButtonState[4] == LOW && buttonState[4] == HIGH) {
      activeChannel++; 
      if (activeChannel == 3) {
        activeChannel = 0;
      }
      delay(5);
  }
  digitalWrite(channelLeds[activeChannel], HIGH);
}

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) {
      switchedOn[activeChannel][i] = !switchedOn[activeChannel][i]; 
      delay(5);
    } else if(lastButtonState[i] == HIGH && buttonState[i] == LOW) {
      delay(5);
    }
  }
}

void updateLeds() {
  for (int i = 0; i < 4; i++) {   
    if(switchedOn[activeChannel][i] == HIGH 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();
    for (int i = 0; i < 3; i++) {
      usbMIDI.sendNoteOff(noteVals[i], 0, 1);
    }
    currentStep++;                                  //increase counter
    
    if (currentStep == 4) {
      currentStep = 0;                              //reset counter
    }
    for (int i = 0; i < 3; i++) {
      if (switchedOn[i][currentStep] == true) {
          usbMIDI.sendNoteOn(noteVals[i], 127, 1);
       }
    }
  }
}