salty, with umami (the taste that comes with monosodium glutamate or MSG) recently added by many experts. The food and beverage industries have developed devices more sensitive than the human tongue to detect flavors, such as bitterness and sweetness, essential for their products. Researchers at the University of Texas and University of Connecticut have gone further, developing electronic methods to test for the presence of all the basic tastes except umami, although these methods have not yet yielded a commercial product.
MORE THAN HUMAN
Sight, hearing, touch, taste, and smell—for each, there are ways the artificial versions fall short of nature, but other ways they can improve on it.They can be extended beyond human norms, or supplemented by sensory modes without human analogues, such as active probing by sonar or laser beams, which work even in the dark, determine the distance and direction to an object, and distinguish between different types of obstacles.
Other advantages are realized by extending artificial vision fur- ther into the electromagnetic spectrum. Humans can see light from 400 to 750 nanometers in wavelength, from violet to red, with the other rainbow colors in between. This is only a tiny portion of the range for electromagnetic radiation,from X-rays and gamma rays with ultrashort wavelengths, to radio waves many meters in wavelength. Within this range lies invisible infrared radiation, which begins at wavelengths beyond 750 nanometers and is generally produced by objects hotter than room temperature. Hold your hand above a hot electric heating coil, or stand in bright sunlight; the warmth you feel is delivered by infrared waves.
The connection between heat and infrared radiation gives an- other way to see in the dark; that is, to discern warm or hot entities like human bodies and internal combustion engines.This is the prin- ciple behind one kind of night-vision goggle, and appropriate sensors provide the same capability to robots. The advantages for military, police, and rescue operations are obvious, and if nursebots or doctorbots ever become realities, their medical diagnoses could be