my BluetoothData variable is set as an integer
Your bluetooth module should be sending out chars, not ints.
But I can see where the problem is and it's with this line here, "int BluetoothData; // the data given from Computer"
BluetoothData should be type char not int. In fact you're already comparing it to chars in your IF statements.
BluetoothData == 's'
All you need to do now is make it so a space char is sent out when no button/key is pressed.