The tutorial outlines a step-by-step guide for building a simple IoT proximity alarm using a Raspberry Pi and PubNub, highlighting the Raspberry Pi's suitability for IoT projects due to its open design and ease of use. It details the construction of a hardware setup involving a Raspberry Pi and an HC-SR04 ultrasonic rangefinder, utilizing a voltage divider to safely connect the sensor to the Pi's GPIO pins. Subsequently, it guides users through coding using Python, incorporating libraries such as GPIO and PubNub, to enable real-time, bidirectional communication with other devices via PubNub's data streams. The project culminates in creating a proximity alarm that not only measures distances but also sends alerts to a web interface and can be upgraded to communicate with a motion detector, demonstrating the potential for scalable, interactive IoT solutions.