#include "KC868.h" KC868 kc868(&Serial2); //create kc868 object void setup() { Serial.begin(115200); delay(2000); kc868.begin(115200);//begin kc868 with baud 115200 boolean ret = kc868.writeSwitchAllOFF(); //close all relay Serial.printf("close all relay "); if(ret) Serial.println("success!"); else Serial.println("fail."); } void loop(){ kc868.poll(); }