const int ECHO_PIN = 5;
const int TRIG_PIN = 7;
const int RED_PIN = 11;
const int GREEN_PIN = 10;
const int BLUE_PIN = 9;

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);
}

void setColor(int r, int g, int b) {
  analogWrite(RED_PIN, r);
  analogWrite(GREEN_PIN, g);
  analogWrite(BLUE_PIN, b);
}

void loop()
{
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  int duration = pulseIn(ECHO_PIN, HIGH);
  float distance =  duration * 0.034 / 2;

  if (distance < 20) {
    setColor(255, 0, 0); // включаем красный 100%
  }
  else if (distance < 50) {
    setColor(191, 191, 0); // включаем желтый 75%
  }
  else {
    setColor(0, 127, 0); // включаем зеленый 50%
    delay(1000);
    setColor(0, 0, 0);   // выключаем зеленый 50%
    delay(1000);
  }
}