Smell detecting robot in the news
Sky News have published Sniffer dogs, beware: Scientists give robot a sense of smell. This sensor has come from Tel Aviv University in Israel.
The banner image on the article shows a robot with familiar yellow wheels, 4WD TT Plastic motors, a Raspberry Pi 4, some kind of motor PCB layer, an HC-SR04 distance sensor on an SG-90 pan and tilt mechanism.
Above the Pi is another tier of electronics, for the sensor, with a receptacle for the sensing. The sensor itself - antennae from a desert locust. The image shows something being dropped in, perhaps a medium for keeping the antennae alive?
There are already common sensors for airborne chemicals like CO2, hazardous gasses and smoke detecting. However according to the original article, this is supposed to detect far more nuanced odours.
It would be interesting to see if it can be made directional enough to drive towards a lemon.
The Sky News article suggests the original paper was published in The Journal of Biosensors and Bioelectronics as The Locust antenna as an odor discriminator, however a purchase is needed to see that content.