i use bluetooth to connect my iphone with arduino uno, i want to let arduino watch my iphone,if any new message came, arduino can display it,how can i do ? is anyone can show me the way? thank you!
That's not an Arduino question, that's an iOS question. Ask in an Apple forum how the iPhone can tell that information to a device connected by Bluetooth. Once you have that information (and the necessary App on the iPhone) you might ask here again how to implement the Arduino part. If you do so, post details about the hardware you want to use for that, a standard Arduino isn't able to do Bluetooth.