The term 'smell SENSOR' can be broken down into two words: 'NOSE' and 'SENSOR'. The NOSE is a part of the body that is responsible for detecting smells. It is made up of millions of tiny nerve endings that detect odors in the air and send signals to the brain. A SENSOR is a device that detects changes in the environment and sends signals to a computer or other device. In this case, the SENSOR is used to detect smells and send signals to a computer or other device.