---

#define PR A0

#define RED 3
#define GREEN 4
#define YELLOW 5

void setup() {
  pinMode(PR, INPUT);

  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(YELLOW, OUTPUT);
}

void loop() {
  int prValue = analogRead(PR);

  if (prValue > 150) {
    digitalWrite(RED, HIGH);
    digitalWrite(GREEN, LOW);
    digitalWrite(YELLOW, LOW);
  }

  if (prValue <= 150 && prValue > 50) {
    digitalWrite(RED, LOW);
    digitalWrite(GREEN, HIGH);
    digitalWrite(YELLOW, LOW);
  }

  if (prValue <= 50) {
    digitalWrite(RED, LOW);
    digitalWrite(GREEN, LOW);
    digitalWrite(YELLOW, HIGH);
  }
}