A smart device is an electronic device, generally connected to other devices or networks via different wireless protocols such as Bluetooth, Zigbee, NFC, Wi-Fi, LiFi, 5G, etc., that can operate to some extent interactively and autonomously. Several notable types of smart devices are smartphones, smart cars, smart thermostats, smart doorbells, smart locks, smart refrigerators, phablets and tablets, smartwatches, smart bands, smart key chains, smart speakers and others. The term can also refer to a device that exhibits some properties of ubiquitous computing, including—although not necessarily—artificial intelligence. Smart Devices can be designed to support a variety of form factors, a range of properties pertaining to ubiquitous computing and to be used in three main system environments: physical world, human-centered environments and distributed computing environments. Smart devices play a fundamental role in today’s Industry 4.0. They are at the center of the Internet of Things (IoT) and smart cities.