According to Nature, humans are capable of smelling at least 1-trillion different odors using around 400 types of scent receptors, which is incredible. Researchers from Germany’s Karlsruhe Institute of Technology have developed an “Electronic Nose” capable of doing the same thing using a scent’s signal pattern.
The sensor is part of KIT’s “smelldect” project, which was designed to develop a low-cost olfactory sensor suit that can be mass-produced and used for everyday devices. The prototype Electronic Nose is only a few centimeters in size and contains all the necessary hardware to evaluate gases, which features a main sensor chip that is connected to a myriad of other sensors using nanowires made of tin oxide.
The device calculates specific signal patterns from those gases based on the resistance changes in the individual sensors. To get the right scent, the sensors compare ambient air molecules against the other gases that are present and look for specific patterns that it has been taught to analyze. The process of educating the chip begins by temporary lowering the resistance of the nanowires using UV light emitted by a LED mounted in the sensor’s housing. Once the molecules from a specific gas settle on the nanowires, that resistance decreases further. It’s that resistance that denotes a particular signal, which the sensor uses to note a particular pattern that correlates to a specific gas- hence it has learned to identify that odor and only takes a few seconds to do so.
The researchers state that the device can be used for various applications, such as controlling the ambient air in smart homes, used for shopping to detect the freshness of produce and meat or used in robots for identification purposes. Smelldect project manager Dr. Martin Sommer goes on to say, “In the future, the electronic nose might be incorporated into all electric gadgets in order to prevent cable fires. Or it can be used in smartphones. When going shopping, everybody might be accompanied by his/her own highly sensitive electronic nose.”