There are several elements that contribute to creating the IoT ecosystem and it is important to understand the role they play in order to have a clear picture about IoT. This will be useful to better understand the projects we will build using Android Things. The basic brick of IoT is a smart object. It is a device that connects to the internet and it is capable of exchanging data. It can be a simple sensor that measures a quantity such as pressure, temperature, and so on, or a complex system. Extending this concept, our oven, our coffee machine, and even our washing machine are all examples of smart objects once they connect to the internet. All of these smart objects contribute to developing the internet of things network. Anyway, it's not only household appliances that are examples of smart objects, but also cars, buildings, actuators, and so on. We can reference these objects, when connected, using a unique identifier and start talking to them.
At the low level, these devices exchange data using a network layer. The most important and known protocols at the base of Internet of things are:
- Wi-Fi
- Bluetooth
- Zigbee
- Cellular network
- NB-IoT
- LoRA
From an application point of view, there are several application protocols widely used in the internet of things. Some protocols derive from different contexts (such as the web); others are IoT-specific. To name a few of them, we can remember:
- HTTP
- MQTT
- CoAP
- AMQP
- Rest
- XMPP
- Stomp
By now, they could be just names or empty boxes, but throughout this book we will explore how to use these protocols with Android Things.
Prototyping boards play an important role in the Internet of things and they help to develop the number of connected objects. Using prototyping boards, we can experiment with IoT projects and in this book, we will explore how to build and test IoT projects using boards compatible with Android Things. As you may already know, there are several prototyping boards available on the market, each one having specific features. Just to name a few of them, we can list:
- Arduino (in different flavors)
- Raspberry Pi (in different flavors)
- Intel Edison
- ESP8266
- NXP
We will focus our attention on Raspberry Pi 3 and Intel Edison because Android Things officially supports these two boards. During the books, we will also use other development boards so that you can understand how to integrate them.
