Answer: A sense of smell.
The project was created by researchers at Karlsruhe Institute of Technology in Germany. Their “electronic nose” is based off of the biological olfactory system, which is made up of 10 million olfactory cells equipped with 400 unique receptors. Those receptors send differing signal patterns to the brain to tell it what they are smelling. The electronic system, which is entirely contained within a chip just a few centimeters in size, works in the same way. However, it is much quicker than the human system in identifying smells that have already been “taught” to it.
According to the researchers, the "nose" still has a lot to learn before it can be incorporated into our devices.
“The difficulty consists in the fact that a scent does not always remain the same. For instance, the smell of a rose in the sun differs from that of a rose in rain,” said the project’s coordinator Dr. Martin Sommer. “Currently, we are training the electronic nose for specific uses which can be chosen universally, however.”
Potential everyday uses include testing the air for harmful particles and determining if food has spoiled.