In settings such as disaster sites, toxic gas leaks can pose a real risk to rescue teams. With that in mind, Spanish researchers have outfitted a small drone to go into buildings and check for such gases, before anyone enters.

Known as the SNAV (Smelling Nano Aerial Vehicle), the 35-gram aircraft is actually based around a commercially-available Crazyflie 2.0 mini quadcopter. That drone was modified by a team from the University of Barcelona and the Institute for Bioengineering of Catalonia, in a project led by researchers Santiago Marco and Javier Burgués.

Equipped with MOX (metal oxide) gas sensors, it can detect even minute concentrations of gases like carbon monoxide and methane, along with other organic volatile compounds such as ethanol, acetone and benzene. It has a sensitivity of down to one part per million in volume (depending on the substance), and it's able to locate the source of an emitted gas by tracking how concentrated that gas is within different parts of a room.

Because GPS units can't track their satellites when indoors, the drone instead autonomously navigates within a building using a series of pre-installed radio-frequency transceivers. In trials that have been successfully carried out so far, six of these were placed in known locations within a building, while another was mounted on the SNAV. Using its own transceiver to communicate with the six others, the copter was thus able to triangulate its current location, plus it could also fly to given locations on command.

And as an added bonus, because the SNAV is so small, it can fly through holes, ducts or other spaces that are too narrow for a person to safely pass through.

A paper on the research was recently published in the journal Sensors.

Scientists from Rice University and NASA have also developed gas-sensing drones, although theirs are designed to work outdoors.

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