ARDUINO FULL CODE
//Arduino code#include <SoftwareSerial.h>SoftwareSerial s(5,6); void setup() {s.begin(9600);} void loop() {int data=50;if(s.available()>0){ s.write(data);}}NODEMCU FULL CODE
#include <SoftwareSerial.h>SoftwareSerial s(D6,D5);int data;void setup() {s.begin(9600);Serial.begin(9600);} void loop() { s.write("s"); if (s.available()>0) { data=s.read(); Serial.println(data); } }