char blueToothVal; //value sent over via bluetooth char lastValue; //stores last state of device (on/off) void setup() { Serial.begin(9600); pinMode(13,OUTPUT); } void loop() { if(Serial.available()) {//if there is data being recieved blueToothVal=Serial.read(); //read it } if (blueToothVal=='n') {//if value from bluetooth serial is n digitalWrite(13,HIGH); //switch on LED if (lastValue!='n') Serial.println(F("LED is on")); //print LED is on lastValue=blueToothVal; } else if (blueToothVal=='f') {//if value from bluetooth serial is n digitalWrite(13,LOW); //turn off LED if (lastValue!='f') Serial.println(F("LED is off")); //print LED is on lastValue=blueToothVal; } delay(1000); }