all IoT devices are directly connected to the Internet. It is not always possible or even desirable to do so. In fact, a good number of IoT devices in a smart home or a factory setting communicate via a non‐IP link such as ZigBee or low‐power wide‐area network (LoRaWAN), which enables these devices to communicate over distances with gateways that interface to standard IP networks. It should also be noted that when such devices use IP, it does not by default mean they are using the public Internet. There could be home and enterprise networks that use IP with data traffic that may never touch the public Internet. Also, even if there is a cluster of non‐IP devices communicating with an aggregation gateway, beyond that gateway, the expectation is that the traffic will be IP‐based. Hence, all the “nodes” of the IoT are expected to create some sort of IP traffic, whether directly, or through some gateway.
Sensing and Actuating: Sensors and actuators are two crucial elements in IoT systems. Sensors are used to perceive and gather information about some dynamic activity (pressure, temperature, altitude, etc.). The collected information is resulted from the interaction of the sensor with the environment.
A more general expression for a sensor is a transducer. A transducer is any device that converts one form of energy into another. A microphone, for instance, is a transducer that takes sound energy and converts it to electrical energy in a useful manner for other components in the system to correlate with.
An actuator is another type of transducer that is found in the majority of IoT systems. Actuators operate in the reverse manner as sensors. They typically take a form of energy and convert it into a physical action. For example, a speaker takes an electrical signal and converts it into a diaphragm vibration which replicates an audio signal.
Connectivity, Communication, and Data Distribution: IoT devices are connected to the Internet either directly or through another device (gateway) where network connections are used for transporting data and interacting with users. Also, these devices allow users to access information and/or control devices remotely using a variety of communication protocols and technologies.
Automation: Regardless of the application, most IoT devices are about automation, such as in industrial automation, business process automation, or home automation. Thus, such devices can generate, exchange, and produce data with minimal or no human intervention.
Intelligence: Intelligence in IoT lies in the knowledge extraction from the generated data and the smart utilization of this knowledge to solve a challenge, automate a process, or improve a situation. There is no real IoT benefit without artificial intelligence, machine learning, Big Data2 analytics, and cognitive algorithms.
Figure 1.1 depicts the abovementioned IoT characteristics.
1.1.2.3 What Exactly Is a Wearable Device?
The term “wearable devices” generally refers to electronic and computing technologies that are incorporated into accessories or garments which can comfortably be worn on the user's body. These devices are capable of performing several of the tasks and functions as smartphones, laptops, and tablets. However, in some cases, wearable devices can perform tasks more conveniently and more efficiently than portable and hand‐held devices. They also tend to be more sophisticated in terms of sensory feedback and actuating capabilities as compared to hand‐held and portable technologies. The ultimate purpose of wearable technology is to deliver reliable, consistent, convenient, seamless, and hands‐free digital services.
Figure 1.1 Characteristics of the Internet of Things.
Typically, wearable devices provide feedback communications of some sort to allow the user to view/access information in real time. A friendly user interface is also an essential feature of such devices, so is an ergonomic design. Examples of wearable devices include smart watches, bracelets, eyewear (i.e.: glasses, contact lenses), headgears (i.e.: helmets), and smart clothing. Figure 1.2 depicts the most important possible forms of wearable devices.
While typical wearable devices tend to refer to items which can be placed external to the body surface or clothing, there are more invasive forms as in the case of implantable electronics and sensors. In the author's opinion, invasive implantables, i.e. ingestible sensors, under the skin microchips, and smart tattoos, which are generally used for medical and tracking purposes, should not be categorized as wearables since they have different mechanisms and operation requirements. The reader should seek other resources which are dedicated to the design and prototyping of such devices.
Figure 1.2 Forms of wearable technology.
1.1.2.4 Characteristics of Wearable Devices
The uses of wearables are far reaching and have exciting potentials in the fields of medicine, well‐being, sports, aging, disabilities, education, transportation, enterprise, and entertainment. The main objective of wearable technology in each of these fields is to smoothly incorporate functional and portable electronics into the users' daily routines. Prior to their existence in the consumer market, wearables were primarily employed in the fields of military technology and health sector.
Generally speaking, wearables share many aspects of the sensing, connectivity, automation, and intelligence characteristics with IoT devices. However, there are a few major differences worth highlighting which will be discussed in the following sections.
Form factor is a hardware design aspect in electronics packaging which specifies the physical dimensions, shape, weight, and other components specifications of the printed circuit board (PCB) or the device itself. Although wearable devices have a small form factor in general, it is practically dependent on the type and the way they are worn (rings and wristbands, as opposed to glasses and clothing).
Smaller form factors may offer reduced usage of material, easy handling, and simpler logistics; however, they typically give rise to higher design and manufacturing costs in addition to signal integrity issues and maintenance constraints.
Moreover, durability, comfort, aesthetics, and ergonomic factors are important when it comes to designing a wearable device. Weight, shape, color, and texture must be carefully considered. The general characteristics of wearable technology are presented in Figure 1.3.
1.1.2.5 IoT vs. M2M
M2M describes the technology that enables the communication between two or more machines. With M2M, one could connect machines, devices, and appliances in a wired or wireless fashion via a variety of communications techniques to deliver services with limited human intervention.
The difference between machine to machine (M2M) and IoT can be confusing to many. In fact, the misconception that M2M and IoT are the same has been a continuing subject of debate in the realm of tech industry.
Both
