SENDING DATA BETWEEN ARDUINO TO ARDUINO OR ARDUINO TO NODE MCU (WORKS FOR BOTH) Use the following code in Sender side #include <SoftwareSerial.h> // connect the 5 of esp to 5 of arduino SoftwareSerial s(5,6); //connect the 6 of esp to 6 of arduino void setup() { s.begin(9600); } void loop() { int data=50; if(s.available()>0) { s.write(data); } } use following code on receiver side #include <SoftwareSerial.h> SoftwareSerial s(D6,D5); float data; void setup() { Serial.begin(9600); } void loop() { if (s.available()>0) { data=s.read(); Serial.println(data); } }