This article in MSNBC discusses a new type of handgun developed at the New Jersey Institute of Technology. The handgun can only be fired if the shooter wears a special RFID watch. The article states in part
[Work on a personalized handgun] was dormant and only recently gained attention in the wake of the December 2012 shootings at Sandy Hook Elementary School in Newtown, Conn. In light of that tragedy, scientists at NJIT publicized a gun that integrates a fire-control system and dynamic-grip recognition.
But nothing in the article explains how Sandy Hook could have been avoided through the use of a personalized handgun. Further, the handgun costs $1,400 plus $400 for the watch. This is an incredibly expensive solution looking for a problem to solve.