A Chicago-based startup is testing a new approach to gunshot detection technology that transforms smartphones into acoustic sensors, potentially saving lives. The testing comes almost two years after the city ended its contract with SoundThinking.
SplitSec, which was founded in Chicago in 2025, has developed an app that is capable of detecting gunshots using the microphones that are already built into Android phones. The technology has the potential to eliminate the need to install fixed sensors, such as the ones used by SoundThinking.
“As I observed events around us, one of the things that was striking is any time there is a gunfire incident, people are unaware, and they stand there for several minutes not knowing what happened. And so the idea was how can we make people aware sooner?” SplitSec founder and CEO Sri Deivasigamani told Fox News Digital.
“We centered our thinking on how can we bring in personal safety for people, and how can you make them be aware and share that awareness. And we’re using technology to help us achieve that, something that we all carry in our own back pockets every day: smartphones,” Deivasigamani added.
The two no-cost trials are taking place in Chicago’s 21st and 42nd wards, according to Block Club Chicago, which reported that there are discussions about expanding testing to the 5th, 29th and 38th wards.
Deivasigamani told Fox News Digital that app users participating in the trials have given SplitSec useful feedback. He said that on some phones the company noticed a high degree of false positives due to sensitive microphones. Another issue that users noted was battery drainage, something SplitSec’s engineers are working on, according to the founder and CEO.
“For some users, on July 27 and 28, the app actually detected gunshots and the user confirmed that they heard gunshots. So, it was an important moment for us,” he said.
Even though SplitSec was not able to verify the gunshots, according to Deivasigamani, users confirmed that what the app picked up was in fact gunfire.
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While the city previously used SoundThinking, which relied on fixed sensors across Chicago, SplitSec uses microphones and computing power already built into smartphones. Deivasigamani told Fox News Digital that advances in smartphone technology have made it possible for something like SplitSec to exist.
“We, you know, could not do this a few years ago, but these days, smartphones are AI-enabled. They have a lot of computing power. So, we designed and built an AI model that runs entirely on your phone,” he said. “And just like your phone can wake up when you say, ‘Hey, Siri’, or ‘Hey, Google’, we have designed our app to wake up only on gunshot sounds.”
Deivasigamani compared SplitSec to Waze, as it does not solely rely on what the phone detects, but also user confirmation, creating a community-powered network.
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Once the app detects the sound of a gunshot, it prompts the user to confirm whether there was in fact gunfire. If the user confirms the sound was a gunshot, SplitSec is then able to distribute the alert to people in a one-mile radius. Additionally, if two or more users confirm the same gunshots, the company is able to triangulate where the shooter is located, allowing them to help people run away from the danger.
“Many shootings have happened where people are actually running towards gunfire because they really quite honestly don’t know where it’s coming from,” Deivasigamani told Fox News Digital.
Chicago is no stranger to gunshot detection technology. The city previously used SoundThinking, formerly known as ShotSpotter, which sparked political battles over its cost and effectiveness. In 2024, the city ended its contract with the company, which meant the Chicago Police Department (CPD) was no longer receiving gunshot alerts from the sensors across the city.
SplitSec is not currently working with CPD and its alerts are meant for users. However, Deivasigamani said that if the company were to work with CPD or Chicago’s Office of Emergency Management and Communications (OEMC), it could provide law enforcement the same map of anonymously reported gunfire that users see.
The use of residents’ smartphones to detect gunfire has raised some concerns about privacy, including questions about whether SplitSec continuously monitors its users. Deivasigamani clarified that the audio analysis takes place entirely on the users’ smartphones and audio clips are only sent to the company if a user reports a false positive. In that case, users are asked about sending the clip to SplitSec, and it is then used to train the model on different sounds to help improve its accuracy.
“We really believe such an app needs to earn people’s trust and needs to be built in such a way that it protects privacy,” he said.
