didnt see the flower smelling robot but anything which does things like smell or taste needs to perform some complex chemistry and its usually done in very specialised integrated circuits which combine the chemical analysis with some form of transducer to read the results.
I was thinking some time ago about a control system for controlling model gliders as a friend of mine flys gliders and asked about not using remote control but an autopilot type system.Its not actually that difficult to do but its a matter of having the time.So theres one idea.Mind you,you might need to read up on control system theory.