Wired has an article covering some of the latest high-tech guns. One in particular is a $10,000 gun that won’t fired unless you’re wearing a special watch.
This year, the highest-tech gun belonged to Armatix. The German firm has an electronic safety that automatically disables the pistol when it’s not within a few inches of a custom wristwatch. The watch sends a wireless arming signal to the gun. If the gun is picking up a signal from the watch, a green LED on the back lights up. Try squeezing the handle without wearing the watch, and you will see a red warning light. Anyone can pick up a limited edition version of the pistol for about 7,000 euro, which is pretty steep for a .22cal plinker. They start shipping next month.
To make the weapon more effective, they should have a way of disabling the lights as you really don’t want your enemy to see where you are.