Building Arduino Projects for the Internet of Things

CHAPTER 3 ■ COMMUNICATION PROTOCOLS

Understanding MQTT is important for building IoT applications, so let’s take a look
at a few scenarios that will help you understand MQTT.

Intrusion Detection System

A simple version of an intrusion detection system is shown in Figure  3-5. It will consist of
three components—the motion sensors that detect intrusions and publish data, a mobile
app that receives this data and alerts the app user, and the component, which is a topic
on an MQTT broker.

Figure 3-4. T h e M Q T T p r o t o c o l

Figure 3-5. Components of the intrusion detection system