Designing intelligent sensors for use in an "Internet of Things" - Part 1In today’s instant-access Internet-centric world, people want and expect to be able to get information when they want it, in the form they need, and at a price they can afford (preferably free).
As Peter Drucker, the greatest management mind of the past 100 years, points out, unlike physical products, information doesn’t operate under the scarcity theory of economics (in which an item becomes more valuable the less there is of it).
On the contrary, information becomes more useful (and valuable) the more there is of it and the more broadly it is disseminated. Individuals and organizations that understand this concept have begun to unlock the tremendous value that has lain fallow in commercial, academic, and nonprofit enterprises throughout the globe by digitizing their mountains of raw data, analyzing it to create meaningful information, and then sending that information via standardized communication links to others within and outside their organizations to accomplish meaningful work.
It would be difficult to overstate the effects that this new paradigm of ubiquitous connectivity has wrought in society economically, intellectually, and in everyday life. People now speak about working in “Internet time,” a frame of reference in which both space and time are greatly compressed.
Information from anywhere on the globe can be distributed to virtually anywhere else quickly and reliably, and Bangalore is now as close to New York City as Boston. In this new world, people work differently than before; individuals or groups can easily team with others from around the corner or around the globe to produce new ideas, new products, or new services, creating fabulous new wealth for some and destroying ways of life for others.
Truly, the new paradigm, which author Thomas Friedman refers to as the “flattening” of the globe, represents a tectonic shift in the way people view their world and interact within it.
What are Intelligent Sensors?
Interestingly, a nearly identical though largely unnoticed sea change is occurring in the rather mundane world of sensors. For the uninitiated, sensors (or sensing elements as they’re sometimes called) are devices that allow a user to measure the value of some physical condition of interest using the inherent physical properties of the sensor.
That’s quite a mouthful for a pretty simple concept, namely monitoring the behavior of one (relatively) easy-to-observe parameter to deduce the value of another difficult-to-observe parameter.
An example of a very familiar nonelectronic temperature sensor (Figure 1 below) is the mercury bulb thermometer, in which a column of mercury contracts or expands in response to the temperature of the material to which it’s exposed.
In this case, the physical condition that we’re measuring is the temperature of the material in which the thermometer is inserted, and the inherent physical property of the sensor that we use for measurement is the height of the mercury in the thermometer.
|Figure 1.1. Two Mercury Bulb Thermometers Showing the Temperature of a Material (Ice and Boiling Water) under Two Different Conditions|
So what kinds of parameters can we measure with sensors? The answer is quite a lot, actually, with the limiting factor generally being our imaginations. Probably the most widely measured parameter is temperature, but other applications include pressure, acceleration, humidity, position, pH, and literally thousands more.
What makes sensors so useful, though, is not just their ability to accurately measure a wide range of parameters but that the sensors can perform those measurements under environmental conditions in which human involvement is simply impossible.
Whether it’s measuring the temperature of molten steel at the center of a blast furnace or monitoring the ocean current thousands of feet below the surface, sensors provide the accurate information that allows us to monitor and control all sorts of important processes.