Who invented sensors

In this case, the mechanical energy form strain or pressure creates electrical signal an electrical charge as a result of the fundamental material behavior of the sensor element. An example. The resulting change in the gauge length of the fiber is measured using interferometry i. Schematic representations of a piezoelectric pressure sensor and a fiberoptic magnetic-field sensor are depicted in Figures and , respectively.

Often sensors incorporate more than one transduction principle; thus, sensors can be conveniently classified simply by their input energy form or signal domain of interest. The committee adopted a sensor taxonomy for this report that is based on the input energy form or measurand as a practical engineering-oriented approach that provides insight into selecting sensors technologies for applications. This approach, however, does not emphasize the underlying mechanisms to the extent that a more science-based taxonomy would; this limitation is particularly telling when multiple response interactions occur.

Nor does this approach lead to rapid identification of low-cost sensors, sensors that exploit a particular type of material, etc. Therefore, alternative sensor taxonomies are also useful.

In addition, research efforts should be directed at improving the understanding of multiple physical responses to a sensing phenomena. For instance, it has been shown that reaction of certain gases on a surface can be effectively measured with a novel sensing approach that uses the differential thermal expansion of a bimetallic material and changes in heat capacity and thermal conductivity of the sensor elements Gimzewski et al.

Sensors, in their most general form, are systems possessing a variable number of components. Three basic components have already been identified: a sensor element, sensor packaging and connections, and sensor signal processing hardware. However, there are additional components to certain sensors. The fiberoptic magnetic-field sensor illustrated schematically in Figure is an example of a common sensor that uses "compound" sensors to transduce a magnetic field into an electric signal.

There are numerous technologies available to convert a magnetic signal into an electrical signal; however, application constraints cost, environmental effects, packaging, etc. The anatomy of a complete sensor system is shown in Figure Technological components in current sensor systems include:. The scope of hardware elements is indicative of widening definition of a sensor attributable to advances in silicon micromachining, micropackaging, and microelectronics.

It is clear from the preceding discussion that modern sensors are much more than a transduction material. Opportunities for introducing new materials in sensors thus arise from three areas: 1 sensor transducer mediums material ; 2 sensor packaging materials; and 3 electronic signal processing devices and readouts.

This report focuses attention on the sensor transducer medium but recognizes the importance, and in some instances dominance, of materials requirements for the other portions of a sensor system. Many recent advances in sensors have not come from the synthesis of new transduction materials except perhaps for chemical sensors but rather from microelectronic innovations in low-cost, large-scale manufacturing of interconnections, microelectronics, and micromachining that have allowed more complex sensor systems to be formed using well-known sensor elements.

One of the most important advances in sensor technology in the last ten years has been the focused development of smart sensors. The definition of "smart" and "intelligent" sensing can be debated.

In general, it is difficult to identify any features in a smart sensor that parallel intelligence in natural systems; however, the terms have become cemented in the technical jargon. The basic tenet of smart sensors is that the sensor complexities must be concealed internally and must be transparent to the host system. Smart sensors are designed to present a simple face to the host structure via a digital interface , such that the complexity is borne by the sensor and not by the central signal processing system.

This report does not address specific technologies associated with smart sensing but instead presents the concept and identifies where and why opportunities exist for new sensor materials as well as for the utilization of existing materials that have not traditionally been used for sensing applications.

Realization of this concept simply means that electronic or optical signal processing hardware is dedicated to each sensor and miniaturized to the point that it becomes a part of the sensor package. Figure provides a schematic representation of a smart sensor that employs "on chip" signal processing within a sensor package. With reference to Figure , a smart sensor would include the sensor, interface circuit, signal processing, and power source.

The primary sensor element within a smart sensor may not be made of a conventional transducer material. Nonlinear and hysteretic materials, previously discarded as being too unreliable or unstable for sensing applications, may now be applied in a sensor that contains its own dedicated microprocessor; the need to burden a central processor with a complex constitutive model or filtering algorithm is thereby avoided.

Applications can be envisioned that exploit the inherent memory or hysteresis of nonlinear materials to reduce the signal processing workload for example, "record" peak temperature. The principal catalyst for the growth of smart-sensing technology has been the development of microelectronics at reduced cost.

On-chip actuators for self-calibration and mechanical compensation may be created using micromachining techniques or thin-film technologies.

Many silicon manufacturing techniques are now being used to make not only sensor elements but also multilayered sensors and sensor arrays that are able to provide internal compensation and increase reliability. It is difficult to predict the future in smart sensing, as the new applications will be driven by the availability of new sensing materials, an improved understanding of the transduction characteristics of "old" materials, and manufacturing techniques for microactuators, microsensors, and microelectronics.

It is clear, however, that the smart-sensing concept creates new opportunities for using novel materials for sensors. The smart-sensing concept makes it possible to avoid the constraint of the paradigm. These advantages of smart sensors are application specific.

There is certainly justification for many applications in distributing the signal processing throughout a large sensor system so that each sensor has its own calibration, fault diagnostics, signal processing, and communication, thereby creating a hierarchical system. Innovations in sensor technology have generally allowed a greater number of sensors to be networked or more-accurate sensors to be developed or on-chip calibration to be included.

In general, new technology has contributed to better performance by increasing the efficiency and accuracy of information distribution and reducing overall costs.

However, these performance enhancements have been achieved at the expense of increased complexity of individual sensor systems. Currently, the practical utility of smart sensors seems to be limited to applications that require a very large number of sensors. The field of sensor technology is extremely broad, and its future development will involve the interaction of nearly every scientific and technical discipline. The basic definitions and terminology in this chapter have been presented to establish some consistency in discussions of sensor applications and technologies, since considerable ambiguity exists in sensor definitions and classifications.

In the remainder of the present report, a sensor classification system based on the measurand, or primary input variable, is used. The committee acknowledges that alternative systems of sensor taxonomy may be useful in particular circumstances, but for the purposes of the present study, the aforementioned scheme was adopted as the most practical option.

In order to accelerate the incorporation of emerging sensor materials in new applications, it is critically important that the sensor materials community be able to readily identify sensing needs and to target those physical phenomena that candidate materials could sense. The definitions of the terms "sensor," "sensor element," and "sensor system" given above have been adopted by the committee in order to facilitate coherent and consistent analysis of sensor technologies.

Many modern "sensors" are in fact sensor systems, incorporating some form of signal processing. Integration of sensor functions into a ''black box" system in which the technical complexity is effectively hidden from the user is a growing trend in sensor development. Of particular interest is the smart sensing concept, which creates new opportunities for using novel materials in sensors, for instance by removing the constraint that sensor elements be linear and noise-free although the cost-effectiveness of such an approach would depend on the application.

Since modern sensors encompass much more than a transduction material, there are many opportunities for introducing new materials in sensor systems, although this report focuses on transducer materials.

Gimzewski, J. Gerber, and E. Observations of a chemical reaction using a micromechanical sensor. Hesse, and J. Zemel, eds. Sensors: A Comprehensive Survey, Vol. New York: VCH. Instrument Society of America. Electrical Transducer Nomenclature and Terminology.

Lion, K. Transducers—problems and prospects. Middlehoek S. Three-dimensional representation of input and output transducers. Sensors and Actuators 2 1 — Sensors: The Journal of Machine Perception 9 Transduction is sometimes referred to by the materials community as a physical or chemical effect.

Some materials exhibit a reciprocal behavior; for example, in a piezoelectric material a mechanical stress generates an electrical charge and vice versa. There are many significant innovations and inventions begin made daily. Micro- and nanotechnology, novel materials, and smaller, smarter, and more effective electronic systems will play an important role in the future of sensors.

To fulfill the promise of ubiquitous sensor systems providing situational awareness at low cost, there must be a demonstrated benefit that is only gained through further miniaturization. For example, new nanowire-based materials that have unique sensing properties can provide higher sensitivity, greater selectivity, and possibly improved stability at a lower cost. Such improvements are necessary to the sensor future. Sensors can improve the world through diagnostics in medical applications; improved performance of energy sources like fuel cells and batteries and solar power; improved health and safety and security for people; sensors for exploring space and the known university; and improved environmental monitoring.

Using a CCD sensor, Steven Sasson built, from the Kodak parts bin, an 8-pound device that gave a black-and-white image of 0. By the late s, complementary metal-oxide semiconductor CMOS architecture had become the choice for logic circuits of all types, especially complex microprocessors and memory devices. A key player in this activity was Eric Fossum. By combining active-pixel sensor APS technology — originally attempted much earlier in MOS — with intra-pixel charge-transfer techniques, the JPL research team was able to envision fully integrated imaging devices, complete with integrated readout circuitry and analog-to-digital conversion in one monolithic CMOS structure.

It was a remarkable advance. By comparison, CCD arrays required supplemental CMOS chips to collect, count and transmit the electrons to the rest of a camera circuit. Fossum and Barmak Mansoorian, another member of the team, soon joined her. A number of viable applications were quickly identified, ranging from medical imaging equipment to webcams.

Over the next few years, dozens of camera makers began the switch to digital imaging, with nearly every camera maker fully converted by Some developed their own image sensors.

At the same time, demand for sophisticated applications was growing quickly.