Cats' whiskers and snakes' tongues work as position sensors. They send messages to their owners of the exact position of a body, relative to its environment as it moves forward in a line. Engineers have gone to lengths to imitate cats' whiskers because the linear position sensor has a range of vitally important uses, especially in modern industrialized society. As society becomes more complex, so position sensors become even more important.
Position sensors can be linear, rotary or angular. As the category names imply, the different kinds of sensor measure the relationship between objects and their particular environments in either a line, angular of circular directions. Each kind of sensor has very important applications in a great variety of situations.
Variable differential transformers are know as LDTVs, and are also position sensors. They have a variety of very useful applications beneath the earth, on it and above it. Applied to scientific measuring devices they are used to predict earthquakes and tsunamis. Their use in predicting weather patterns has immense significance for agriculture, travel and industry.
Though the chief executives of oil companies are blamed for undersea oil leaks and the consequent environmental disasters, the truth may be that linear position sensors could actually be to blame. One of their many uses is to monitor the performance and safety of undersea equipment. Failure of one sensor could begin a chain of reactions ending in an environmental disaster. The fact that such disasters rarely occur, illustrates how important they are in our complex industrial society.
Robotics has become a vitally important area of endeavour. Robots can build cars and other machines. They already do a number of domestic chores and mundane services such as serving speeding fines on motorists. Electroacoustic transducers are deployed and used for purposes as varied as scoring systems in bowling alleys and surveillance systems to detect movement, perhaps the movements of thieves as they approach a house.
Promisingly, LDTVs can now be used for military purposes, making the heroics of fighter pilots obsolete. Unmanned planes, or drones, can be sent to drop bombs on enemy targets or take pictures of military installations. Higher up in the atmosphere they must be used extensively in space travel in various complex guises. As human beings colonise space, so the humble sensor will become an ever more integral part of everything that moves in heaven or on earth.
The many uses that sensor devices are put to implies that they are subject to severe environmental forces. For example, a LDTV fixed to an industrial machine in an assembly plant, or in a pump beneath the sea, will be exposed to vibrations, temperature variation and corrosion. Fortunately there are types of sensors that are housed in a sliding core that does not touch the inside of the tube that houses it. Thus, damage to the sensor is prevented.
Like twinkling city lights, a multitude of linear position sensors work ceaselessly in an endless variety of purposes. Across the globe, from deep mines to complex urban conurbations and into space, their unseen presence is crucial. From a deep sea tank to the financial stochastic pored over by traders they monitor and facilitate the workings of the world.