Martinsville schools to install gunshot detection devices in all buildings Device is about the same size as a smoke detector Taj Simmons, Reporter Tags: The district will install gunshot detection devices in all of its buildings. The purchase and installation of these devices was funded by an approved $200,000 request to the Virginia Department of Education. The device, which is about the same size as a smoke detector, automatically notifies dispatchers and police if it hears the sound of a gunshot. The technology is also able to tell law enforcement where in the building the sound came from. “It’s a tool that’s out of sight, out of mind,” said Martinsville City Schools director of security T.J. Slaughter. “It’s peace of mind, it’s there when you need it.”