testing data sending using mega to nodemcu

megasendata_practice

//connect the rx<-0/tx->0 on nodemcu rx/tx after mega and nodemcu done uploading this code.
/*-----------------for mega------------------------*/
void setup() {
  Serial.begin(115200);
}

void loop() {
  Serial.write("0");
  delay(500);
  Serial.write("1");
  delay(500);
}

/*---------------------for nodemcu-------------*/
#define LED D4
void setup() {
  pinMode(LED, OUTPUT);
  digitalWrite(LED, HIGH);
  Serial.begin(115200);
  Serial.println("Blinking on GPIO pin " + String(LED));
}
 
void loop() {
  if (Serial.available()) {
    char s = Serial.read();
    if (s == '1') {
      digitalWrite(LED, HIGH);
      Serial.println("on");
    }
    if (s == '0') {
      digitalWrite(LED, LOW);
      Serial.println("off");
    }
  }
}