Pipe bombs and butcher knives. Who would have expected middle school students to bring such weapons into school  buildings or on campuses here in Rowan County?

But they did in recent incidents, fortunately without hurting anyone. This is the reality of life today. A kid doesn’t have to be holding a gun to be armed and dangerous. Between confused kids, desperate criminals and homegrown terrorists, the nation is more aware than ever of how vulnerable we are to violence.

So are businesses, including those that provide security systems. This week officials a Methuen, Massachusetts, elementary school held a simulated shooting to see how “active shooter” technology could help police respond quickly. Sensors installed in classrooms and hallways were activated by the sound of dummy rounds being fired in the school library. Police officers instantly tracked the shooter’s movements down a hallway and stopped him.

“It’s amazing, the short, split-second amount of time from identification of the shot to transmission of the message,” said Metheun’s police chief, Joseph Solomon. “It changes the whole game. Without that shot detection system, we wouldn’t know what was going on in the school. … Valuable, valuable time can be lost.”

That brings back memories of SWAT officers gathering around Columbine High School in 1999, not knowing where the shooters were. And Virginia Tech. And Sandy Hook Elementary. And so on.

Sensors cannot prevent the first shots from being fired, but they could help limit losses by pinpointing the shooter’s location for police. Shooter Detection Systems installed the Methuen system — said to be the first in a public school in the U.S. —  but other companies are also marketing “active shooter” systems to schools, malls, airports and other public buildings. Some say the systems could become as common as smoke detectors and fire sprinklers.

Technology is ramping up to detect danger, but it would be a poor replacement for school resource officers. Sensors could not have knocked the knife out of a West Rowan Middle School student’s hand, for example. Instead, technology is a tool to help officers do their job.  We’d like to live in a time and place where “active shooters” are unheard of, but that time is long past.