The Internet of Things (IoT) utilises the power of cloud technology to form a network of interconnected devices such as computers, sensors, MCUs, mobile phones, home appliances, etc. The global internet network is comprised of a “web” of underwater cables that run from continent to continent, as shown in Figure 1.

Figure 1: Global Internet Network

Note that this is just an approximate representation of the network. Major cities such as Sydney and Perth include a major communication node that connects to other communication nodes on surrounding continents such as New Zealand and Papua New Guinea. Homes and businesses within Australia utilise the National Broadband Network (NBN), which provides an internet connection via underground cables both on land and in the seabed. Cell towers, on the other hand, provide a connection to the internet for mobile phones and devices utilising an IoT-enabled SIM card via line-of-sight communication. Well-developed urban areas containing large buildings improve connectivity via reflected signals. Many cell towers are connected to the network of underground cables, while other cell towers are not. For isolated cell towers, line-of-sight communication with non-isolated cell towers is required. In some remote locations where there are no underground cables nor nearby cell towers, satellites are required to provide an internet connection. The main reason for utilising underwater cables is due to the curvature of the Earth and lack of line-of-sight for effective communication. With such a network established, there are numerous possibilities when it comes to embedded solutions, such as turning on an air-conditioning unit from outside of a house and monitoring the temperature of a room remotely. Figure 2 represents the concept of cloud communication between a mobile application and an ESP32 Wi-Fi module to control an LED.

Figure 2: Remote Communication

There are a total of seven elements comprising this communication system:

  • Mobile app: A mobile app is used to communicate with a Dynamic Domain Name Server (DDNS) in sending a message such as “ON.”
  • DDNS: A DDNS is used to point to a router’s worldwide unique public IPv4 address.
  • ISP: An ISP issues an IPv4 address to a router, which is dynamic, i.e., changes after a few days or all the way up to after a few months, depending on the structure of the ISP.
  • Router: A router allows incoming data to pass through a specific port to a specific device’s IP address, i.e., port forwarding.
  • ESP32 module: An ESP32 module, connected to the same forwarded port, “listens” for incoming data.
  • MCU: An MCU can “listen” for incoming data from the ESP32 module.
  • LED: An LED can be controlled based on the embedded source code of the MCU in relation to the incoming data.

This concept can be expanded to control elements of a home air conditioner system, such as turning it ON or OFF and setting the temperature.