#define TRIG_PIN 5
#define ECHO_PIN 18
#define GREEN_LED 19
#define RED_LED 21
long duration;
int distance;
int threshold = 15; // cm, adjust as needed
void setup() {
Serial.begin(115200);
pinMode(TRIG_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
pinMode(GREEN_LED, OUTPUT);
pinMode(RED_LED, OUTPUT);
}
void loop() {
// Clear trigger
digitalWrite(TRIG_PIN, LOW);
delayMicroseconds(2);
// Send pulse
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
// Read echo
duration = pulseIn(ECHO_PIN, HIGH);
distance = duration * 0.034 / 2; // cm
Serial.print("Distance: ");
Serial.print(distance);
Serial.println(" cm");
// Parking logic
if(distance < threshold) {
digitalWrite(RED_LED, HIGH); // Space full
digitalWrite(GREEN_LED, LOW);
} else {
digitalWrite(RED_LED, LOW);
digitalWrite(GREEN_LED, HIGH); // Space free
}
delay(500);
}