Its reaction with the odour molecules changes a detector's electrical resistance, and this signal is fed into a neural net (the closest that computer technology has got to imitating the pattern-recognising abilities of networks of nerve cells) to work out what is being smelt.
Along these lines, last June, Google connected together 16, 000 computer processors into a giant machine vision learning neural net and let them loose on YouTube.
His team at the Neural Systems Laboratory, University of Washington, hopes to take brain-computer interface (BCI) technology to the next level by attempting to teach robots new skills directly via brain signals.