IMAGINE being able to record a smell and play it back later, just as you can with sounds or images. Engineersat the Tokyo Institute of Technology in Japan are building an odourrecorder capable of doing just that. Simply point the gadget at afreshly baked cookie, for example, and it will analyse its odour andreproduce it for you using a host of non-toxic chemicals.The device could be usedto improve online shopping by allowing you to sniff foods or fragrancesbefore you buy, to add an extra dimension to virtual realityenvironments and even to assist military doctors treating soldiersremotely by recreating bile, blood or urine odours that might help adiagnosis.The system will use 15 chemical-sensing microchips, orelectronic noses, to pick up a broad range of aromas. These are thenused to create a digital recipe from a set of 96 chemicals that can bechosen according to the purpose of each individual gadget. When youwant to replay a smell, drops from the relevant vials are mixed, heatedand vaporised. In tests so far, the system has successfully recordedand reproduced the smell of orange, lemon, apple, banana and melon.