[Aeddan (OP)]

We all know why drugs dogs are use but why is there no machine that can do the same?
What's blocking the path ? Surely cracking fusion energy is not easier than creating a portable machine that is as good as a police drug dog . . .

[Bored chemist]

Two things.
Evolution has about a billion year head start on us and
there's no market because the machine would have to be cheaper to build than a dog.

[alancalverd]

....and as much fun to operate. And as versatile. I watched a man trying to run out of Milan airport one day with a dog hanging on to his briefcase. The dog handler just laughed, and a guard at the exit stopped the runaway "Please I check your bag and return the dog, sir." Dogs in the uniformed services are given a rank from cadet to "airdog" or equivalent, and receive a promotion and pension on retirement.

Bees are cheaper but less fun and more specific. It is claimed that you can train a bee in a few minutes to spot less than 10 molecules of any one target volatile material. They then spend a couple of hours on active duty, get a big sugar reward, and are released into the wild.

[Origin]

Surely cracking fusion energy is not easier than creating a portable machine that is as good as a police drug dog . . .

Well we currently have neither.  I would wager there is a lot more money being spent on fusion than on an artificial dog nose, especially since a dog works perfectly well.

[Aeddan (OP)]

Two things.
Evolution has about a billion year head start on us and
there's no market because the machine would have to be cheaper to build than a dog.

We can cheat & studdy evolutions homework. I read a while back about cancer smelling machines in the process of being made.
Police already have a portable breath analyzing machine.
Not every police officer can have a dog but all of them have a potential to shove a smelling machine into they hats ( yes those hats would need to be the same size as a dogs lungs to function correcty. Which correct me if I am wrong here but would be very funny to see)

[alancalverd]

The breathalyser is very crude compared with even the human nose. The difference is in requirement and specification: for breath alcohol you need a very accurate measure of quite a high concentration of just one material, delivered in a very precise manner. For drugs,  explosives, or hidden people, you need to be able to detect a ridiculously small number (some say as few as 2) molecules of any one of a range of targets which the perpetrator has done his best to hide.

I've worked on breath analysis of a few analytes such as hydrogen, hydrogen peroxide, and COVID. Again, the collector was very precise and the concentration of the target was well within the scope of A level analytical chemistry - several orders of magnitude above a canine threshold.

Not ever policeman or soldier needs a dog, but there are enough folk who want to handle dogs in uniform, and enough dogs that enjoy the work, that the K9 van is usually available when needed, and the occupant is often multiskilled.  You can tell a dog to search an area that is inaccessible to Constable Plod's big boots, or to roam around a dockside where he is "just a dog" and ignored until he finds something of interest.

At one demonstration I learned  that the British army had been asked to supply search and rescue dogs to the Polish police after an earthquake. Apparently it was quicker to teach the dogs Polish commands than to teach the police officers English, and they were on the scene within 2 days.

It is also interesting to note that a lot of sniffer dogs are recruited from rehoming centers. Some dogs are unsuitable as pets because they have obsessive traits, but these are just  what is required: they are easily retrained to hunt for cocaine, gun oil, or whatever, instead of shoes, and aren't distracted by noise or other animals when they are at work.

[alancalverd]

Postscript

If you've ever had a selenium diode catch fire (you'd have to be over 50 to remember these) you will have had a machine that smells worse than a dog.

[Aeddan (OP)]

Dose this mean we have machines that have surpassed a super human smeller?
Or is there still something our nose can do a machine cannot?

I am pondering what is blocking the next leap in the tech.
When we talk about detecting Co2 in ppm. Is detecting cocaine ppb . ppt or pp(omg what is that number) ?

[paul cotter]

Not wishing to derail this topic but I have to reply to Alan. I am, unfortunately, of an age to remember selenium rectifier stacks and even copper oxide rectifiers and have often heard of the stench when a selenium rectifier fails but it is something I have never experienced. This is strange since I have been experimenting with various bits of electrical equipment since I was a kid ~8years old. I have heard that tv repair men would often be told "the dog is sick" as an explanation for the stink when such a rectifier had failed in the set needing repair.

[vhfpmr]

Postscript

If you've ever had a selenium diode catch fire (you'd have to be over 50 to remember these) you will have had a machine that smells worse than a dog.

When I was a kid I had some EHT rectifiers that consisted of a foot long Paxolin tube filled with a stack of selenium discs. After amusing myself melting them with a soldering iron for a few minutes I felt distinctly green round the gills.

[paul cotter]

A foot long? what were they obtained from, an xray machine? Selenium is an essential element for human health where it exists as selenomethionine and selenocysteine which are components of some enzymes(can't remember which) but is highly toxic if a certain level is exceeded, normal nutritional requirements in the microgram range, ~250μ.

[vhfpmr]

They were in the CRT supply of a home made oscilloscope with a VCR97. About 2kV according to this.

[paul cotter]

I made a home made oscilloscope from a design in "practical wireless" using the cheap 3bp1. Despite it's low bandwidth it worked ok but for one problem: the magnetic field from the mains transformer caused a ripple in the display and no amount of shielding would eliminate it. A foot long for 2kv seems a lot but then again in those days solid state rectifiers were primitive and mercury vapour jobs would be used if the power requirements were anyway significant.

[alancalverd]

I made a home made oscilloscope from a design in "practical wireless" using the cheap 3bp1.

Me too. Had lots of fun with it until it was superseded by a Russian one. I've no idea what happened to them after I left the parental home!

[Zer0]

Dose this mean we have machines that have surpassed a super human smeller?
Or is there still something our nose can do a machine cannot?

I am pondering what is blocking the next leap in the tech.
When we talk about detecting Co2 in ppm. Is detecting cocaine ppb . ppt or pp(omg what is that number) ?

Donno much about Smell...
I'll say a few words n your queries might be answered by somebody else.

Guessing Machines have surpassed Humans in that regards.
Perhaps one thing a Mechanical Nose can't do is to be Runny.
But Surely it could be Programmed to produce Mucus.

Perhaps it's the lack of Financing in Research & Development preventing or slowing down Leaps in Science & Technology.

I had read somewhere that People spend more on Pet Products vs Governments granting Aid towards Fusion Reactors.

ps - Caring for Pets is Essential.
No compromises should be made there.
Clean Energy can Wait, it's not like the World is gonna end due to climate change or global warming.