DC Police Department monitors gunshots with acoustic rooftop sensors | Hacker News Reader

DC Police Department monitors gunshots with acoustic rooftop sensors

washingtonpost.com

54 points_pius42 comments

This system has been used in Minneapolis for a while already, and you can view the maps of local gunshots detected by the system.[1] Once in a while, the police have to test the system with police gunshots to calibrate the microphone network.[2] ShotSpotter appears, based on the experience of Minneapolis, to have rather limited usefulness for deterring or prosecuting gunshot crimes. But maybe it aids prevention of crime if police respond to where the gunshots are usually fired with preventive patrols.

[1] http://www.minneapolismn.gov/police/statistics/crime-statist...

[2] http://www.startribune.com/local/blogs/224931852.html

Looking at the ShotSpotter reports... this is crazy. I was aware that some shootings happen, but it seems like Minneapolis has 4-5 shootings per week on average. Really depressing idea. 4-5 in a year would probably be a high number for my area (in the UK though).

Yeah, it's really apples-to-oranges to compare anywhere in the US to the UK -- even the state with the tightest gun laws is more permissive.

FWIW I live in Chicago and in my neighborhood >1-2 a year is high and causes a commotion.

That being said you go 20mi south and it's a different story.

I came here to post the same links to the Minneapolis PD ShotSpotter page. What's more depressing is that nearly all the shootings are concentrated in a few North Minneapolis neighborhoods. I've hung out in those neighborhoods a lot and I would hear gunshots, see shot-out street lights, etc. especially at night.

Crime is way down in Minneapolis since the mid-1990s though, apparently in 1995 North Minneapolis blocks had the highest rate of violent crime per capita in the nation.

Looking at this table of murders by city internationally, it should be pretty obvious what all these locations have in common...

http://en.wikipedia.org/wiki/List_of_cities_by_murder_rate

Milwaukee uses this system too, unfortunately there's not a map of just ShotSpotter results.

Saginaw, Michigan has been using the shotspotter for years. It's a huge joke in the community. It doesn't even work most of the time.

Allegedly there are plenty of ex-police chiefs and such involved with this company, and government grants pay for the installation of the product. It lets authorities know, i n theory, when and where gunshots occur. That's it.

It's not tied into some Hollywood satellite video system where two seconds after a gun is fired, the aftermath and fleeing suspects are caught on tape. It doesn't even produce any evidence that can be used in court.

It is disturbing that a city of 50,000 would need something like this.

In any case, all the advocates of the system claim is that it "lets you know when and where a gunshot occurs". That's it. I see no one claiming more, yet can appreciate how knowledge when and where a gunshot occurs can be useful to law enforcement.

> It is disturbing that a city of 50,000 would need something like this.

It's sad that a police department of a city of 50,000 is using the purchase of such a system to justify their budget.

Do you think ShotSpotter paid a PR agency to get this article published?

http://www.paulgraham.com/submarine.html

(Not that that's necessarily a bad thing. I'm just curious.)

Most likely, yes. It's extremely common, not sure you can draw any conclusions from that.

It's certainly possible -- I guess you could email the author and ask whether he was pitched the idea or not -- but the article says the data came from a public records request and the analysis was done by the Post. I don't think you can jump to conclusions any way.

The acoustic sensors have made the Washington Post before, in the context of actual investigations.

Previous discussion about acoustic gun detection systems: https://news.ycombinator.com/item?id=4034528

I have never seen these on the roof, however, I have seen them posted on telephone poles and light posts all throughout Chinatown

http://www.washingtoncitypaper.com/cover/2009/0213/1.jpg

That just looks like a "standard" camera box. Probably some kind of little NVR in it, along with a wireless network node of some sort (mesh, 4G, etc.).

There isn't any single company that supplies those, but there are a handful of security dealers that essentially assemble them.

That one looks like it might be old, the PTZ on the bottom looks like a really old Pelco unit.

Ah Pelco where 3.5" floppy is still required for updates, still, in 2013.

I was told that many of the boxes in Chicago just have fake cameras and a blue flashing light to let you know you're being "watched". Not sure if it is true or not but you can buy fake security cameras.

You can certainly buy fake cameras. You can also buy real cameras for under $40 and just not hook them up.

Many cities are starting to deploy these municipal surveillance boxes, many with grant funding. So, it's hard to say which are real and which are not anymore.

A very related link to a project I'm unaffiliated with, but which I've been aware of for some time: Homicide Watch. It follows homicides in DC (largely shooting related) from incident through trial and the wider ramifications. Politico-journo-techno-mashup. http://homicidewatch.org/

These systems are pretty good at detecting fire crackers and backfiring cars. E.g., check out this recent map of results:

http://www.minneapolismn.gov/www/groups/public/@mpd/document...

Only a few of those points are actually shootings.

Wired article about Shot Spotter:

http://www.wired.com/wired/archive/15.04/shotspotter.html

The Oakland police dept have been using ShotSpotter for 5+ years.

They've actually been in DC for 8 years. The article is about crunching the data they've collected so far.

I remember this level in Deus Ex. Luckily I hadn't really developed my firearms tree; more hacking and lock picking.

Troy, NY tried this for a few years. They got rid of it because it's expensive and ineffective.

http://www.timesunion.com/local/article/Troy-will-turn-off-S...

> The network covers only a third of the city, focusing on the police districts with the most violent crime.

That's refreshingly novel. Usually police coverage is concentrated in the less violent but wealthier districts.

I heard rumors this year that these are installed in my neighborhood in Berkeley, but that they don't work at all on July 4th due to all the fireworks false positives.

Gosh, where I live, it'd be useless during much of the year, what, with the rednecks and the backfiring vehicles and such. ;)

Is there an app for that?

(I suspect there will be, soon. It's a simple matter of software – and battery life – once everyone is carrying a networked microphone.)

Would this be good for listening for breaking glass?

That would be great for detecting breakins and car theft, no?

Actually they could develop a new model you install inside a house and listens for windows breaking.

That would be better than the expensive of putting a sensor on every window of a house for an ADP type system.

This already exists. http://www.benchmarkmagazine.com/intruder_tests_detail.php?t...

Why limited it to that. It could be extended to monitor all sounds including spoken voice. That then could be turned into text and they could detect if people speak about crime. Stop crimes and terrorism at the root!

Who said the military industrial complex doesn't create anything of benefit? LOL

The gall of this surveillance state. What about the Constitution? How dare they monitor gun-owning Patriots like this!

What a terrible idea. If you know it exists and want to shoot someone, just get a bunch of random people to shoot in the air all over town. Or even better get a few speakers and some youtube videos of people shooting. Audio is so easy to fake.

you aren't going to make a speaker generate the sharp pressure rise the devices are listening for over any significant distance.

Fire crackers are a better bet.

just get a bunch of random people to shoot in the air all over town

So now instead of just shooting someone, you're also engaging many conspirators in your plan?

Law enforcement tactics are often discounted using contrived scenarios that criminals simply don't undertake. Firstly because most criminals generally aren't masterminds, and for those that actually are, the proposed circumvention activities usually leaves even more of a trace that ends up with people in jail.

> If you know it exists and want to shoot someone, just get a bunch of random people to shoot in the air all over town.

The cops catch a few and likely trace the requests back to you via use of plea bargains.

> Or even better get a few speakers and some youtube videos of people shooting.

Oh yes, even better. Traceable evidence, with fingerprints and maybe purchase records! Not to mention the system to set them all off at the right time.

By the way, use of these tactics escalate the murder charge to first degree when they catch you, as it's pretty clearly premeditated.

Or you could go the cheapest and easiest route and get a silencer, as mentioned in the article, clearly most people don't care who hears them.

...Are you actually arguing that every single would-be murderer, premeditated or otherwise, has the forethought and resources to organize a city-wide conspiracy to shoot guns into the air at the exact moment of their crime?

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