The Tueller Drill is a Augmented Reality self-defense training exercise to prepare against a short-range knife attack when armed only with a holstered handgun. This application requires the use of a RED laser.

Sergeant Dennis Tueller, of the Salt Lake City, Utah Police Department wondered how quickly an attacker with a knife could cover 21 feet (6.4 m), so he timed volunteers as they raced to stab the target. He determined that it could be done in 1.5 seconds. These results were first published as an article in SWAT magazine in 1983 and in a police training video by the same title, "How Close is Too Close?"[1][2]

A defender with a gun has a dilemma. If he shoots too early, he risks being accused of murder. If he waits until the attacker is definitely within striking range so there is no question about motives, he risks injury and even death. The Tueller experiments quantified a "danger zone" where an attacker presented a clear threat.[3]

The Tueller Drill combines both parts of the original time trials by Tueller, and presents a Laser training pistol drill which provides verbal commands to begin. Using a simplified computer vision will identifies the first laser shot that strikes the target area, and displays the elapsed time for the laser strike . This is useful to practice both presentation as well as firing.