Researchers at the New Jersey Institute of Technology in Newark are building a handgun designed to fire only when its circuitry and softwareof an authorized shooter.
Sensors in the handle measure the pressure the hand exerts as it squeezes the trigger. Then algorithms check the shooter's grip with stored, authorized patterns to give the go-ahead.
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"We can build a brain inside the gun," said Timothy N. Chang, a professor of electrical engineering at the New Jersey Institute of Technology who devised the hardware for the grip-recognition system. "The technology is becoming so cheap that we can have not just a computer in every home, but a computer in every gun."
The main function of the system is to distinguish a legitimate shooter from, for example, a child who comes upon a handgun in a drawer. Electronics within the gun could one day include Global Positioning System receivers, accelerometers and other devices that could record the time and direction of gunfire and help reconstruct events in a crime investigation.
For a decade, researchers at many labs have been working on so-called smart, or personalized, handguns designed to prevent accidents. These useto recognize authorized shooters, or require the shooter to wear a small token on the hand that wirelessly transmits an unlocking code to the weapon.
At the New Jersey Institute of Technology, Michael L. Recce, an associate professor in the department of information systems, decided instead to concentrate on the shooter's characteristic grip. Recce created the software that does the pattern recognition for the gun.
Typically, it takes one-tenth of a second to pull a trigger, Recce said. While that is a short period, it is long enough for a computer to match the patterns and process the authorization.
New Jersey Institute
To bring Recce's recognition software to life, Chang created several generations of circuits using off-the-shelf electronic components. He equipped the grips of real and fake handguns with sensors that could generate a charge proportional to the pressure put on them.
The pressure on the grip and trigger are read during the beginning of the trigger pull. The signals are sent to an analog-to-digital converter so that they can be handled by the digital signal processor. Patterns of different users can be stored, and the gun programmed to allow one or more shooters.
At first the group worked mainly with a simulated shooting range designed for police training. "You can't have guns in a university lab," Recce said.
The computer analysis of hand-pressure patterns showed that one person's grip could be distinguished from another's. "A person grasps a