IoT, or the Internet of Things, depends on sensors. So much so, there would not be any IoT, IIoT, or for that matter, any type of Industry 4.0, at all, without sensors. As the same factors apply to all the three, we will use IoT as a simplification. However, some basic definitions first.

As a simple, general definition, IoT involves devices intercommunicating with useful information. As their names suggest, for IIoT and Industry 4.0, these devices are mainly located in factories. While IIoT is a network of interconnected devices and machines on a plant floor, Industry 4.0 goes a step further. Apart from incorporating IIoT, Industry 4.0 expands on the network, including higher level systems as well. This allows Industry 4.0 to process and analyze data from IIoT, while using it for a wider array of functions, including looping it back into the network for control.

However, the entire network has sensors as its basis, supplying it with the necessary raw data. Typically, the output from sensors is in the form of electrical analog signals, and IoT creates the fundamental distinction between data and information.

This distinction is easier to explain with an example. For instance, a temperature sensor, say, a thermistor, shows electrical resistance that varies with temperature. However, that resistance is in the form of raw data, in ohms. It has no meaning to us, until we are able to correlate it to degrees.

Typically, we measure the resistance with a bridge circuit, effectively converting the resistance to voltage. Next, we apply the derived voltage to a measuring equipment that we have calibrated to show voltage as degrees. This way, we have effectively converted data into information useful to us, humans. However, we can still use the derived voltage to control an electric heater or inform a predictive maintenance system of the temperature of a motor.

But information, once we have derived it from raw data, has almost endless uses. This is the realm of IoT, intercommunicating useful information among devices.

To be useful for IoT, we must convert the analog data from a sensor to a digital form. Typically, the electronics required for doing this is the ADC or Analog to Digital Converter. With IoT applications growing rapidly, users are also speeding up their networks, thereby handling even larger amounts of data, making them more power efficient.

Scientists have evolved a new method for handling large amounts of data that does not require the IoT devices to have large amounts of memory. The devices send their data over the internet to external data centers, the cloud. There, other computers handle the proper storing and analysis of the data. However, this requires higher bandwidth and involves latency.

This is where the smart sensor makes its entry. Smart sensors share the workload. A sensor is deemed smart when it is embedded within a package that has electronics for preprocessing, such as for signal conditioning, analog to digital conversion, and wireless transmission of the data. Lately, smart sensors are also incorporating AI or Artificial Intelligence capabilities.