leslie radar using arduino

radar.c

const int pwPin = 7;
const int led = 11;

void setup()

{
  Serial.begin(115200);
  pinMode(pwPin, INPUT);
  pinMode(led, OUTPUT);
}


void loop() {
  long pulses;
  long cm;
  static int latch = 0;
  static long nextlatch = 0;
  pulses = pulseIn(pwPin, HIGH);
  //cm = (pulses / 147.2) * 2.54;
  //Serial.print(cm);
  //Serial.print("cm");
  //Serial.println();

  long now = millis();
  if (pulses < 3500 && pulses > 300) {
    if (nextlatch < now) {
      latch = 1; 
    }
    nextlatch = now + (10*1000);
  } else {
    latch = 0;
  }

  Serial.print("latch: "); Serial.print(latch);
  Serial.print(" now: "); Serial.print(now);
  Serial.print(" nextlatch: "); Serial.print(nextlatch);
  Serial.print(" pulses: ");
  Serial.print(pulses);
  Serial.println();

  if (latch == 1) {
    analogWrite(led,250);
    delay(100);
    analogWrite(led,0);
    delay(50);
    analogWrite(led,250);
    delay(50);
    analogWrite(led,0);
    latch = 0;
  }
  
  delay(500);
}