#define TRIG_PIN_1 2
#define ECHO_PIN_1 3
#define TRIG_PIN_2 4
#define ECHO_PIN_2 5

const int ledPins[] = {6, 7, 8, 9, 10};
const int numLeds = sizeof(ledPins) / sizeof(ledPins[0]);

const int detectionThreshold = 50;

void setup() {
  Serial.begin(9600);
  
  pinMode(TRIG_PIN_1, OUTPUT);
  pinMode(ECHO_PIN_1, INPUT);
  pinMode(TRIG_PIN_2, OUTPUT);
  pinMode(ECHO_PIN_2, INPUT);
  
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);
    digitalWrite(ledPins[i], LOW);
  }
}

void loop() {
  long duration1, distance1;
  long duration2, distance2;

  digitalWrite(TRIG_PIN_1, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN_1, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN_1, LOW);
  duration1 = pulseIn(ECHO_PIN_1, HIGH);
  // distance1 = duration1 * 0.034 / 2;
  distance1 = (duration1 / 2) / 29.1;

  digitalWrite(TRIG_PIN_2, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN_2, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN_2, LOW);
  duration2 = pulseIn(ECHO_PIN_2, HIGH);
  // distance2 = duration2 * 0.034 / 2;
  distance2 = (duration2 / 2) / 29.1;

  if (distance1 < detectionThreshold) {
    for (int i = 0; i < numLeds; i++) {
      digitalWrite(ledPins[i], HIGH);
      delay(200);
    }
  }

  if (distance2 < detectionThreshold) {
    for (int i = 0; i < numLeds; i++) {
      digitalWrite(ledPins[i], LOW);
      delay(200);
    }
  }

  delay(100);
}