Are all the devices which support BLE 4.0 can be connected in my iOS devices which support BLE 4.0?

Question

About Bluetooth Low Energy. I know iPhone 4S, iPhone 5, iPad 3 with iOS 5.1 and above support BLE 4.0. And I read the sample code TemperatureSensor from Apple. My question is what is the requirement for the sensors? In another words, what kind of sensors can be connected in this application? Are all the devices which support BLE 4.0 can be connected in my iOS devices which support BLE 4.0?

Answer 1

BLE communication is based on GATT (General Attributes), which is essentially an exchanges of the values of different characteristics under a service. If you've read the TemperatureSensor sample code, you must have seen that it starts to discover devices according to a service UUID, and then read/write characteristics, still based on UUID, under the service. Therefore, as long as the sensor supports BLE and you know about its services (its UUID, its characteristics and properties), you can program your iOS app to communicate with it. Some of the services are 'pre-defined' by Bluetooth SIG, so you can find the information of these services on Bluetooth SIG website.