A microsensor is a miniature electronic device functioning similar to existing large-scale sensors. With recent micro-electromechanical system (MEMS) technology, microsensors are integrated with signal-processing circuits, analog-to-digital (A/D) converters, programmable memory, and a microprocessor, a so-called smart microsensor.
Current smart microsensors contain an antenna for radio signal transmission. Wireless microsensors are now commercially available and are evolving with more powerful functionalities.
In general, a wireless microsensor consists of a sensing unit, a processing unit, a power unit, and communication elements. The sensing unit is an electrical part detecting the physical variable from the environment. The processing unit (a tiny microprocessor) performs signal-processing functions, i. e. integrating data and omputation required in the processing of information. The communication elements consist of a receiver, a transmitter, and an amplifier if needed.The power unit provides energy source with other units
Basically, all individual sensor nodes are operated by a limited battery, but a base-station node as a final data collecting center can be modeled with an unlimited energy source. Under the microscale, nanosensors are used in chemical and biological sensory applications to deliver information about nanoparticles.
As an example, nanotubes are used to sense various properties of gaseous molecules, as depicted in the figure below. In developing and commercializing nanosensors, developers still need to overcome high costs of production and reliability challenges. In the near future, there is tremendous room to enhance the technology and implement various nanosensors in real-life applications.
Photo: Three-dimensional (3-D) model of three types of single-walled carbon nanotubes, like those used to make certain nanosensors (created by Michael Ströck on February 1, 2006)
Extracted and edited from “Handbook of Automation – Springer – 2009”