False alarms are a costly matter and we realize that when we see a sea of people gathered around buildings from an evacuation triggered by a smoke detector set off by a false alarm.

Australia has been trying out chemical sniffers especially tuned to paint and marker vapors to catch vandals in the act. This could help business owners with the real concerns while not having any effect on explorers.

http://www.gizmag....iti-sensors/37440/

They don't react to animals or explorers. It is similar to substance specific leak detectors used in cooling equipment rooms that ignore vapors from housekeeping, maintenance and industrial processes but sniff out and report cooling gas leaks. Explorers run into industrial leak sensors and cheerfully ignore them. It's not a concern since exploration doesn't set them off.

This looks like a fine idea, but, well, for trains, not buildings, cause the threat are not only taggers, but also scrapers and common vandals, so simple motion sensors work best (ok, that's debatable ;) And I bet that no one cares about explorers "goodwill".

Posted by Antash This looks like a fine idea, but, well, for trains, not buildings, cause the threat are not only taggers, but also scrapers and common vandals, so simple motion sensors work best (ok, that's debatable ;) And I bet that no one cares about explorers "goodwill".

Nothing is immune. This would be a good thing for visible outdoor and exterior locations that appeal to vandals, but also frequented by birds and animals that trip motion detectors. They don't want people up on the tower galore but their main concerns are real damage caused by vandals and scrappers. The cost of live operator confirmation for each bird or cat event would get out of hand so it's all in good signal processing.

Selective response chemical sensors coordinated with motion detectors could have very good accuracy for catching tagging in progress while ignoring whiffs of paint from a nearby auto shop or movements explorers or animals. Motion sensors are dirt cheap. This can be very practical once the cost of sniffing sensors drop enough. All sounds good in theory and real world examples from Australia sounds promising.

The thermostat tells your furnace to switch on when the house gets cold. You might not have given this any thought. The computer checks for absence of flame and chimney airflow before it gives gas. Once it gives gas, it checks for successful light off and constantly monitors for blow out. You want it to pickup problems without false alarms. The computer checks the order of events so it's less likely to miss a fault and resists bypass. If you jump a sensor, the program sees the improper order of events and won't move forward. All of the decision making process fits on a chip and they're very cheap to mass produce.

Would it work to just use vapour sensors for vandals, as well as having a sensor attached to wires and pipes, that will notify them if the circuit is broken?

Posted by Darthbindy Would it work to just use vapour sensors for vandals, as well as having a sensor attached to wires and pipes, that will notify them if the circuit is broken?

Some scrappers are brazen enough to take live wires from power poles. People lose electricity or service as soon as it happens. Additional sensors might do not good to prevent those. News articles often mention that some scrap yards buy obvious things like phone booths and statues hacked from local landmarks no questions asked.

Posted by Deuterium Some scrappers are brazen enough to take live wires from power poles. People lose electricity or service as soon as it happens. Additional sensors might do not good to prevent those. News articles often mention that some scrap yards buy obvious things like phone booths and statues hacked from local landmarks no questions asked.

There was a scrapper caught after stealing and selling cast iron manhole covers. He stole hundreds before they arrested him.

As a redundant security measure it's of course a good idea, but still not in every case (thought I wrote it, well, I didn't), I mean it's a matter of costs, and if it would pay off. I'm skeptic.

Btw I thought it's possible to regulate the sensitivity of motion sensors so that they won't get set off by small animals?

As for the scrap topic: one day while I was in the forest I found something that looked like someones stash - shining copper wires, about 4cm thick! It was so shiny that it was more like pink than the typical copper brown, never seen something like it. It had to be stashed there the same day. Huh, it was my lucky day! Finders keepers, right?
I read that this kind of wires are used for example in trains cause they can stand up to 2000 amps, so I was afraid that they won't want to buy it from my at the scrap yard, however... no questions asked, also I saw their current pricing for electric traction - yup, in "plain text" ^^

Posted by Antash As a redundant security measure it's of course a good idea, but still not in every case (thought I wrote it, well, I didn't), I mean it's a matter of costs, and if it would pay off. I'm skeptic.

You hit the nail right on the head. Farmers don't invest their effort into catching animals harmless to their crop. It's a matter of cost on the principle of no harm, no foul. It's a means of separating explorers and others that do no harm from vandals who have already caused damage that is costly to repair by triggering an alarm signal only after detecting vandalism.