Building an IoT Alarm Module

In the previous chapter, we explored the Raspberry Pi’s GPIO port and built a basic alarm system. We learned about different communication protocols and worked with a set of sensors, which we accessed using the GPIO port. In this chapter, we will enhance our basic alarm system using a Raspberry Pi Pico W, a public Message Queuing Telemetry Transport (MQTT) server, and the MQTTHQ web client (Figure 6.1).

We will use a Raspberry Pi Pico W to host a passive infrared (PIR) sensor and buzzer as we build our IoT alarm module. In our setup, when motion is detected, a motion message is sent to the MQTT server and viewed using the MQTTHQ web client:

Figure 6.1 – IoT-powered alarm module using MQTT

We will send a buzzer message to the Raspberry Pi Pico W from the MQTTHQ web client to activate the buzzer. This Raspberry Pi Pico W and MQTTHQ web client setup forms the foundation of our IoT home security system.

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