boolean led= false; char command; String string; void setup() { Serial.begin(9600); pinMode(6, OUTPUT);//connect led to pin 6 } void loop() { if (Serial.available() > 0) //check for input data {string = "";} while(Serial.available() > 0) { command = ((byte)Serial.read()); if(command == ':') { break; } else { string += command; } delay(3); } if(string == "on") { analogWrite(6, 255); delay(10); Serial.println(string); led = true; } if(string =="off") { analogWrite(6, 0); delay(10); led = false; Serial.println(string); } if ((string.toInt()>=0)&&(string.toInt()<=255)) { if (led==true) { analogWrite(6, string.toInt());//type casting to integer Serial.println(string);//printing the int value delay(10); } } }