int val; void setup() { pinMode(10, OUTPUT); //Positive Terminal of LED pinMode(8, OUTPUT); //Negetive Terminal of LED Serial.begin(9600); } void loop() { digitalWrite(8, LOW); //Allways LOW //Read input from bluetooth module: if( Serial.available()){ val = Serial.read(); } //Input key switch switch(val){ case '0': digitalWrite(10, LOW); //LED OFF break; case '1': digitalWrite(10, HIGH); //LED ON break; default: break; // default code (should never run) } }