system
Given the following post, respond as if you're commenting on Reddit:
human
Are there electronic devices to substitute sniff dogs for forensics?

Is a device that sniffs illicit substances around a house a thing that is possible ?? If it exists, why didn’t it replace sniffing dogs already?
(Sorry for the flair, wasn’t sure which flair fits.)
gpt
Yes, there are chemical detection machines - you may have seen one used at the TSA screening line in an airport.  Of course, those are meant to detect explosive residues, and are largely just theater, but theoretically one could be made that detects a variety of narcotics.

However, it's going to be a long time before dogs can be replaced.  Their noses are so sensitive, require no engineering (just training), and they know how to cover the space inside the house.  Compare that to a Roomba, which can't even navigate stairs, and takes a long time to slowly build a model of the 3D (well, really 2D) space it's in... If they even do that, in their current iteration.

Also, part of the sensitivity of the dog nose is that it detects airborne particulate.  Our security theater explosive detection machines that don't move also can only detect chemicals they can directly sample.  So, imagine how long it would take for humans to go around swabbing every surface in a house to try to get a sample of meth somewhere.

TL;DR - scientifically, dogs are pretty good at sniffing.

Edit: also, you can always give the dog a little kick while no one's looking, say that it barked, and get your warrant that way.  Robots would mess that up.