// blink_esp32.ino
const int LED_PIN = 5; // common built-in LED / wire external LED to GPIO2
void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  Serial.println("Blink start");
}
void loop() {
  digitalWrite(LED_PIN, HIGH);
  Serial.println("LED ON");
  delay(500);
  digitalWrite(LED_PIN, LOW);
  Serial.println("LED OFF");
  delay(500);
}