Bluetooth as a push button

All you need to do now is make it so a space char is sent out when no button/key is pressed.

Not a good idea. How will you determine how often to send the space?

What is needed is to set BluetoothData to some value that is not a valid "command" after processing that one "command".

my BluetoothData variable is set as an integer, and if I change it to string

A string is a NULL terminated ARRAY of chars. No one suggested changing the type to string. Change it co char - ONE char. Or set the value to -27.