int pinRelay = 3; //管脚D3连接到继电器模块的信号脚 void setup() { Serial.begin(9600); pinMode(pinRelay,OUTPUT);//设置pinRelay脚为输出状态 } void loop() { digitalWrite(pinRelay,HIGH);//输出HIGH电平，继电器模块闭合 Serial.print("LED illumination"); delay(3000); //等待3000毫秒　 digitalWrite(pinRelay,LOW);//输出LOW电平，继电器模块分开 Serial.print("LED is off"); delay(2000);//等待5000毫秒　 }