Application domains of the Internet of Things solutions are wide. Most prominent applications include (among others) ^[1]:

• building and home automation,
• smart water,
• smart metering,
• smart city (including logistics, retail, transportation),
• smart animal farming,
• industrial IoT,
• precision agriculture and smart farming,
• security and emergencies,
• healthcare and wellness (including wearables),
• smart environment,
• energy management,
• robotics,
• smart grids.

Smart homes are one of the first examples that come to mind when talking about the domain applications of the Internet of Things. Smart home benefits include reduced energy wastage, the quality and reliability of devices, system security, reduced cost of basic needs, etc. Some home automation examples are environmental control (that monitors and controls heating, ventilation, air conditioning and sunscreens), electrical charging of vehicles, solar panels for electrical power and hot water, ambient lighting control, smart lighting for aquaria, home cooking, garage doors, smart plant watering systems indoors and outdoors, baby monitors, timed pet food dispensers, monitoring perishable goods (for example, in the refrigerator), remote monitoring (for instance, of washer cycle status), tracking and proactive maintenance scheduling, event-triggered task execution. Home security also plays a significant role in smart homes. Example applications are automatic door locks, sensors for opening doors and windows, pressure, motion and infrared sensors, security cameras, notifications about the security (to the owner or the police) and fitness related applications.

In smart city, multiple IoT-based services are applied to different areas of urban settings. The aim of the smart city is the best use of public resources, improvement of the quality of resources provided to people and reduction of operating costs of public administration ^[2]. Smart city can include many solutions like smart buildings, smart grids for improving energy management, smart tourism, monitoring of state of the roads and occupation of parking lots, public safety, environment monitoring, automatic street lighting, signalling with smart power devices, control of water levels for hydropower or flood warnings, electricity generating devices like solar panels and wind turbines, weather monitoring stations. Transportation in smart cities may include aviation, monitoring and forecasting of traffic slowdowns, timetables and current status, navigation and route planning, as well as vehicle diagnostics and maintenance reports, remote maintenance services, traffic accident information collection, fleet management using digital tachographs, smart parking, car/bicycle sharing services ^[3]. IoT in transportation makes cars connected.

Smart grid is a digital power distribution system. In this system, information is gathered using smart meters, sensors and other devices. After these data are processed, power distribution can be adapted accordingly. Smart grids are used to deliver sustainable, economical and secure electricity supplies efficiently.

In precision agriculture and smart farming IoT solutions can be used to monitor the moisture of the soil, conditions of the plants, control microclimate conditions and monitor the weather conditions in order to improve farming ^[4]. The goal of using IoT in agriculture is the maximization of the harvest, reducing operational costs, being more efficient in general and reducing environmental pollution using low-cost automated solutions. An interaction between the farmer and the systems can be done using a human-machine interface. In the future smart precision farming can be a solution for such challenges like increasing worldwide demand for food, a changing climate, and a limited supply of water and fossil fuels ^[5].

Similar to precision agriculture that is part of IoT in industry, smart factories also tend to improve the manufacturing process by monitoring of pollutant gases, locating employees and with many other solutions.

Industrial IoT and smart factories are part of the Industry 4.0 revolution. In this model, modern factories are able to automate complex manufacturing tasks, thanks to the Machine-To-Machine communication model and thanks to it, provide more flexibility in the manufacturing process to enable personalised, short volume products manufacturing with ease.

In the healthcare and wellness, IoT applications can be used for monitoring and diagnosing of patients, managing of people and medical resources. It allows to remotely and continuously monitor the vital signs of patients to improve medical care and wellness of patients ^[6]. Important part of the smart welfare are wearables that include wristbands and smartwatches that monitor the level of activity, heart rate and other parameters. Smart healthcare includes remote monitoring, care of patients, self-monitoring, smart pills, smart home care, Real-Time Health Systems (RTHS) and many more. Medical robotics can also be part of the healthcare IoT system that includes medical robots in precision surgery or distance surgery; some robots are used in rehabilitation and hospitals (for example, Panasonic HOSPI ^[7]) for delivering medication, drinks, etc. to patients.

Wearables used in IoT applications should be highly energy efficient, ultra-low power and small sized. Wearables are installed with sensors and software for data and information collected about the user. Devices used in daily life like Fitbit ^[8] are used to track people health and exercise progress in previously impossible ways, and smartwatches allow to access smartphones using this device on the wrist. But wearables are not limited only by wearing them on the wrist. They can also be glasses that equipped with the camera, a sports bundle attached to the shoes or camera attached to the helmet or as a necklace ^[9].