In this section, we will give a complete example of a Central-Peripheral communication using Android. Peripheral is the device which advertises itself and Central responds to the advertisement and initiates the connection process. Normally, the peripheral is an IoT device which broadcast its identity and central is a cell phone which connects to the device to exchange data.

We have discussed various scenarios where a device can act as peripheral and the cellular phone can act as a central to start the communication process. Since we are not focusing on the hardware in this chapter, the complete cycle of Central-Peripheral communication is acquired by one of the software tools discussed in Chapter 2, BLE Hardware, Software, and Debugging Tools. We are using Nordic Connect Application to deploy a GATT server as a peripheral. We will configure the server with minimum efforts which will advertise built-in heart rate service.

Once the server will be deployed, we will move to the Android application which will act as a central. The application will explore the services and characteristics advertised by the server. It will also write the values to the peripheral.