#define LED 5
#define POT A4
volatile int c = 1;
volatile int val = 0;
volatile int n = 0;
volatile bool num = 0;
volatile bool pot = 0;
volatile bool lin = 0;
void setup() {
  pinMode(LED, OUTPUT);
  pinMode(LED_BUILTIN, OUTPUT); 
  Serial.begin(9600); 


  cli(); 
  TCCR1A = 0; 
  TCCR1B = 0; 
  TCCR1B |= (1 << WGM12);
  TCCR1B |= (1 << CS10) | (1 << CS12); 
  OCR1A = 15625 - 1; 
  TIMSK1 |= (1 << OCIE1A); 
  sei(); 
}

void loop() {
 if (num) {
  Serial.println(n);
  num = 0;
  n++;
  }
if (pot) {
  while(pot){
  analogWrite(LED, analogRead(POT) / 4);}
}
if (lin){
  digitalWrite(LED_BUILTIN, HIGH);
      delay(100);
      digitalWrite(LED_BUILTIN, LOW);
      lin = 0;
}
}

ISR(TIMER1_COMPA_vect) {
  
  switch (c) {
    case 1:
      num = 1;
      digitalWrite(LED, LOW);
      break;
    case 2:
    lin=1;
      break;
    case 3:
    pot = 1;
      break;
    case 4:
    pot = 0;
      digitalWrite(LED, LOW);
      break;
    case 5:
      digitalWrite(LED, HIGH);
      break;
  }
  c++; 
  if (c > 5) c = 1; 
}