Nowadays, we are pretty much inseparable from a small, thin, usually black device that connects us to one another and to the world: our mobile phones. These devices are computing marvels, miniaturized chips with powerful microprocessors that are much more powerful than desktop computers from a decade ago. Add to that capacious connections to Wi-Fi networks that allow broad connectivity to the world and Bluetooth, which allows narrow and close-by secure connection to edge devices. Soon, Wi-Fi 5G and Bluetooth 6 will increase these connections to geographically disparate networks, to terabytes of data and to millions of interconnected devices making up the Internet of Things.
Also attached to those powerful phones are a variety of sensors, including cameras, temperature sensors, light-sensitive screens, and something perhaps little known to you before this chapter: accelerometers. An accelerometer detects and monitors vibration in rolling machines and can be used to obtain positional data in 3D space over time, which is 4D data. All cell phones are equipped with these sensors, which provide positional data in the following form: