Health or environment, safety or security, energy, automotive or food, it is nowadays very hard to find a sector in which sensors do not play a key, and increasingly pervasive, role. Their applications, nowadays often referred with the terms smart or 4.0 industrial revolution according to the specific sector involved, generally require a very fast technological handover from research results to the manufacturing levels.
AISEM is the Italian Association of researchers in universities, research centers and industries, working, since 1995, at improving and disseminating the science and the applications of Sensors and Microsystems in any scientific, economic and industrial sector.
A sensor translates any quantity into an electric signal enabling electronic circuits to process data whose meaning is outside the circuit itself but it is a quality of the environment at which the sensor is interfaced. Indeed, electronics has been defined as “the science and technology which deals primarily with the supplementing of man’s senses and his brain power by devices to collect and process information, transmit it to the point needed, and there either control machines or present the processed information to human beings for their direct use (Everett, Proc. IRE, 1952)”. Modern sensors, either wired and wireless, can be therefore defined as the electronic senses of the Information-Communication technology that is nowadays carrying everyone’s life into the so-called Internet of Things (IoT) scenario.
Sensors differ in terms of sensed quantity, fabrication technology, working mechanism, and applications. They are usually classified respect to the nature of the stimulus at which they respond. To this regard, sensors are divided in sensors of physical quantities, sensors of chemical quantities and sensors of biological quantities.
A different sensors classification is based on their sensing principle that may be physical, chemical or biological. Physical sensors are normally based on physical phenomena with noteworthy exceptions: for instance molecular thermometers use the relationship between fluorescence and temperature to provide the measure of temperature at molecular scale. On the other hand, chemical sensors are obviously based on chemical phenomena however in some cases physical phenomena may be used, a typical example is the measure of oxygen concentration exploiting the paramagnetic properties of the oxygen molecule. Or, finally, we can deal with sensors based on biological principles, the biosensors, that make use of biological molecules such as peptides, nucleotides, proteins, DNA, and living cells to measure biological and chemical quantities.