The symbiotic relationship with computers is not unidirectional, going from our brains to the machine. We also receive information from computers. Today, this information is expressed in numbers, text, graphs, fixed images, and animated sequences displayed on screens, or in sounds emitted by speakers. But with portable computers, personal digital assistants, hand-held computers, increasingly miniaturized telephones, videophones, and pagers, there will be a need to transmit information to the brain in a way that is more personalized, more discreet, and more private.
We are at the dawn of a revolution in the means of communication, going from electronic machines to humans. What we call the "communications revolution" is in fact the prehistory of a phase that will take place in the first decade of the twenty-first century. When it comes to communications, we havenít seen anything yet! Bioelectronic ears, eyes, and noses that can hear, see, smell, transmit, and, especially, interface with human beings, are already being developed by high-tech companies. The reception of information from computers and communications machines is taking a new direction. For example, a small California company has developed a combination earphone-microphone placed in the ear. The innovation is in the clever relationship between the earphone, the microphone, and the information emission unit. There are no wires; everything is transmitted by Hertzian waves. You can talk with your computer while moving about, or keep your portable telephone in your pocket while talking in a very low voice with the person at the other end. The microphone placed just outside the ear electronically reduces ambient noise by taking into account the constant distance between the ear and the mouth. In addition, using an original process, the microphone picks up the sounds transmitted by the bones of the skull. This considerably amplifies the emission quality of the voice of the person speaking, even when he or she is only whispering. Other companies are developing implants placed deeper in the ear, similar to certain hearing aids, which allow a computer with voice synthesis to speak directly into the ear.
Artificial noses have been developed by a number of laboratories in the world. One of them, created at the University of Manchester, is already using molecular electronics. A sensor functions like the olfactory mucous membrane. It consists of conducting polymers containing groups of chemicals that recognize the molecules responsible for various odors. When a molecule carried by the flow of air lands on a receptor, a change in the electric conduction of the polymer occurs, which produces an olfactory "fingerprint" or profile of the substance. A neural network then compares this information with the various families of odors in its memory. The computer screen displays the specific pattern of the odor and announces the name of the substance. A palm-sized vapor detector has been developed by Sawtek, a Florida-based company. Up to 200 known chemicals ranging from toxic gases to moldy food can be sniffed out using four piezoelectric crystals coated with different polymers that absorb target vapors.
Synthetic retinas that can distinguish shapes are the precursors of the eyes of future generations of robots. Until now, the artificial retinas used in the vision systems of robots or smart missiles have been based on silicon. A Japanese team at the Fuji laboratories has used bacteriorhodopsin, a protein that acts as a photoreceptor in certain photosynthetic bacteria that live in salt water, in particular, in the Dead Sea. One of the important characteristics of this artificial retina is its capacity to react in a few microseconds to changes in light intensity. Researchers at Johns Hopkins Universityís Wilmer Eye Institute and at the Massachusetts Institute of Technology have developed artificial retinas in the form of silicon implants packed with transistors that sit on the surface of the retina. Alan Chow, an opthalmologist and founder of the start-up OptoBionics, is working on a subretinal implant made of a collection of microphotodiodes implanted behind the retina.