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Exclusive: Flock Safety Reveals Gunshot Sensors Tied to Cameras

The device, called the Raven, is going through beta testing now and will launch for general sales in January. It’s designed to detect gunshots, as well as other sounds such as glass breaking, and activate nearby cameras.

The Flock Safety Raven device mounted to a pole on a sidewalk.
Flock Safety
A gunshot rings out, and overhead a camera begins recording.

With a new product, this is what Flock Safety hopes to achieve. And more than that, it wants to make the product cheap enough and fast enough to set up that any local police department can use it.

The product — going through beta testing now and hitting the market for general sale in January — is an audio sensor called Raven. It’s meant to detect gunshots, along with other crime-related noises such as glass breaking and tires screeching, and then activate nearby cameras as well as alert the police.

Garrett Langley, co-founder and CEO of Flock Safety, hopes Raven will allow law enforcement to respond to crimes faster and relay more information to detectives. In a best-case scenario, Raven could put police on the scene before an incident escalates.

The camera tie-in is critical. Gunshot detection is nothing new — ShotSpotter has been doing it for years — but the whole selling point of Raven is that it will connect to Falcon, Flock Safety’s camera that helps police locate vehicles of interest.

“The audio event is critical. But to me, it’s that integrated solution about how are we actually going to solve homicide, how are we going to prevent a homicide?” Langley said. “And that’s what we’re selling. So could it work alone? Sure, but we would never sell it alone, because I think that that would be a truly ineffective solution.”

Like the Falcon camera, the Raven audio device is solar powered, so it doesn’t need to tap into an existing power source. Raven can trigger cameras to begin recording, but it relies on cameras to do the actual processing to determine what kind of sound has occurred. Unlike ShotSpotter, which has a center staffed with people working to validate that a gunshot was, in fact, a gunshot, Flock Safety plans to rely solely on its AI algorithms to identify a sound.

“Something loud or something with a particular frequency happens in a particular area … then we start recording, and then we start filtering through the machine learning on the edge to decide, in more or less granular buckets, this is a gunshot, this is glass breaking, [these are] some of the things that we’re interested in. And then there’s everything else, which is all the things we’re not interested in, [like] human voice and all this other stuff, and that stuff is just dumped immediately,” said Davis Lukens, Flock’s vice president of product. “Then once we have it [through that] first set of filtering, that’s when it gets backhauled to the Falcon, and then sent off to the cloud for additional processing and more granular detection of — you know, maybe it is a firework that sounds very similar to a gunshot.”

Lukens declined to give an exact accuracy rate — which will change between different environments, and likely between different types of sound — but said an aggregate accuracy rate would be north of 90 percent.

Even though the tie-in with cameras means a possible extra layer of validation for whatever sounds the Raven picks up, the very nature of the product is at odds with the criticisms racial justice activists have been making for years. Oftentimes cities will deploy technologies such as license plate-reading cameras and gunshot sensors in areas with more low-income residents or people of color, which means that those technologies will tend to send police to those areas more often. As a result, the department will log more crimes in those areas, which will make it seem like those areas need even more policing.

That begins with the choice of where to put a camera or sensor, which is up to the city, not the company. Regardless, Langley said he believes people in those areas want the police to stop the crime happening in their neighborhoods.

“What we believe is that if you go to the average citizen who lives in a community and ask them ... ‘Do you actually want more police involvement?’ In my experience, the answer is a resounding yes,” he said. “If you ask a broad topic, a national question of over policing, you get very mixed views.”

Langley said the company watches for best practices and good policies among its customers, and looks to offer such practices and policies to its other customers.

Additionally, the company offers transparency tools to its customers — again, their choice to use or not — that can give residents a clearer idea of the activities being detected. These tools can give police the ability to show where gunshots are happening, or placate residents who think they heard a gunshot when a car backfired.

“One of my goals would be to push our police chiefs to use our transparency report to show [their] community that they actually don’t have as much gun violence as they think,” Langley said.

The company will be working with customers over time to identify other noises that could be associated with crimes. For example, it could train the Raven to listen for the type of saws criminals might use to steal catalytic converters. That capability could be pushed out to all deployed Ravens in an over-the-air update.

“For the city where my parents live, they fortunately don’t have a lot of gun violence, but they do have car break-ins, they have illegal street racing, they have catalytic converters theft,” he said. “Those are still all events — crimes — that begin with audio, and then visual.”

The company has been beta testing the device in a number of areas, including Fort Worth, Texas, and Clarkesville, Ga. It’s offering a kind of free trial to customers; any agency that’s already a customer or signs up to deploy 15 or more Falcon cameras between Sept. 1 and Dec. 31 will get one square mile of coverage from Raven for a year for free.

After that, the company plans to charge $25,000 per square mile per year for Raven, not including the cost of the cameras.

“I believe that every single city deserves this type of technology,” Langley said.
Ben Miller is the associate editor of data and business for Government Technology. His reporting experience includes breaking news, business, community features and technical subjects. He holds a Bachelor’s degree in journalism from the Reynolds School of Journalism at the University of Nevada, Reno, and lives in Sacramento, Calif.