מרחק, נוכחות ותנועה

const int TRIG = 9;
const int ECHO = 10;
const float V = 0.0343;                  // speed of sound: 343 m/s = 0.0343 cm/us

void setup() {
  Serial.begin(9600);
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
}

void loop() {
  digitalWrite(TRIG, HIGH);                // 10 us trigger pulse
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  unsigned long t = pulseIn(ECHO, HIGH, 30000UL);   // 0 = timeout
  Serial.print("t = "); Serial.print(t);
  if (t == 0) {
    Serial.println(" us  no echo");
  } else {
    Serial.print(" us  d = "); Serial.print(V * t / 2, 1);
    Serial.println(" cm");
  }
  delay(100);
}

const int TRIG = 9, ECHO = 10, BUZZ = 8;   // BUZZ: passive buzzer
const unsigned int GAP[] = {0, 500, 200, 0};   // ms between beeps
unsigned long lastBeep = 0;

void setup() {
  Serial.begin(9600);
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
}

void loop() {
  digitalWrite(TRIG, HIGH); delayMicroseconds(10); digitalWrite(TRIG, LOW);
  unsigned long t = pulseIn(ECHO, HIGH, 30000UL);
  float d = (t == 0) ? 999.0 : t / 58.0;   // no echo = far away
  int z = (d > 100) ? 0 : (d > 50) ? 1 : (d > 25) ? 2 : 3;
  if (z == 0) noTone(BUZZ);
  else if (z == 3) tone(BUZZ, 2000);       // stop: continuous tone
  else if (millis() - lastBeep >= GAP[z]) {
    tone(BUZZ, 2000, 60);                  // short beep
    lastBeep = millis();
  }
  Serial.print("d = "); Serial.print(d, 1);
  Serial.print(" cm  zone "); Serial.println(z);
  delay(60);
}

const int PIR = 2, LAMP = 7;
const unsigned long HOLD = 30000UL;        // ms after the last motion
unsigned long lastMotion = 0;
bool lampOn = false;
void report(const char *msg) {
  Serial.print("t = "); Serial.print(millis() / 1000.0, 1);
  Serial.print(" s  "); Serial.println(msg);
}
void setup() {
  Serial.begin(9600);
  pinMode(PIR, INPUT); pinMode(LAMP, OUTPUT);
  delay(60000UL);                          // PIR warm-up
  Serial.println("ready");
}
void loop() {
  unsigned long now = millis();
  if (digitalRead(PIR) == HIGH) {
    lastMotion = now;                      // motion: restart the timer
    if (!lampOn) {
      lampOn = true; digitalWrite(LAMP, HIGH); report("lamp ON");
    }
  }
  if (lampOn && now - lastMotion >= HOLD) {
    lampOn = false; digitalWrite(LAMP, LOW); report("lamp OFF");
  }
}