Combining push button and Serial.read to make led on and off.

Other Hardware LEDs and Multiplexing
5

Please edit it to use code tags like in you first post :wink:

And a little tip, once you start numbering variables, arrays are the answer :wink: See Gammons Tip 1 (and for more).

But worst, you give pins names but never use them! Go and use the names!

And don't just make all the variables global.

After some updates

const byte SwitchPins[] = {2, 4};
const byte MotorLedPins[sizeof(SwitchPins)] = {3, 5};
bool buzzer = false;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);

  for(byte i = 0; i < sizeof(SwitchPins); i++){
    pinMode(SwitchPins[i], INPUT);
  }
  
  for(byte i = 0; i < sizeof(MotorLedPins); i++){
    pinMode(MotorLedPins[i], OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  
  for(byte i = 0; i < sizeof(SwitchPins); i++){
    if(digitalRead(SwitchPins[i]) && !buzzer){
      digitalWrite(MotorLedPins[i], HIGH);
      buzzer = 1;
    }
  }
  
  if (Serial.available() > 0)
  {
    Serial.print("Buzzer state: ");
    Serial.println(buzzer);

    if (Serial.read() == 'R')
    {
      Serial.println("LEDs set off");
      buzzer = false;
      for(byte i = 0; i < sizeof(MotorLedPins); i++)
      {
        digitalWrite(MotorLedPins[i], LOW);
      }
    }
  }
}