This post is also available in: heעברית (Hebrew)

“Smart guns” have entered the national conversation in the US following President Barack Obama’s plea to end the rampant gun violence plaguing the nation.They are supposed to make gun ownership and use safer, and prevent injuries and deaths. But what are smart guns? Knowledge of what are the underlying technologies, their uses and applications, is often missing from the discussion. While personalised weapons technology can definitely increase gun safety, decrease death and injuries, there are no fool-proof and all encompassing solutions.

The idea of “smart guns” finds its origins in a 1995 US National Institute of Justice (NIJ) study that recommended a technological solution to reducing the prevalence of incidents where police officers were killed by assailants grabbing their weapons. Recently, Obama’s appeal mentioned specific recommendations on federal actions aimed at promoting the development of advanced gun-safety systems. The term “smart gun” has become a catchall for a number of technologies, which we’ll look at here.

The first type of solution are proximity sensors. This class of technologies is designed with the need to protect officers whose guns have been taken off them in mind. The basic conception employs a Radio Frequency Identification (RFID) tag worn by the user, and an RFID sensor in the gun itself. The system works by sensing the proximity of an authorised RFID chip. If it’s not present, locking mechanisms prevent the gun from firing. Gun prototypes with RFID firing prevention mechanisms were demonstrated as far back as 1996.

Proximity of the RFID tag to the sensor is of course not a sure-fire method of determining whether a gun is is held by its rightful owner, but the simplicity of use often outweighs the limitations. Moreover, as RFID tags can be easily reproduced, this method doesn’t ensure that only a particular user can fire a gun. Rather, that only a user with an appropriate identification tag can. This allows for easy weapons exchange between permitted users, such as partners on patrol.

The other prominent method of ensuring a gun only fires in the right hands is based on biometrics. While easy weapons exchange out in the field allows for great flexibility, it can turn into a disadvantage in the home, where any member of a household could get their hands on the RFID chip. Biometrics systems rely on on unique, measurable physical characteristics to prevent the misuse of a firearm.

The most common method of biometric identification currently relies on fingerprints, with capacitance imaging sensors being prevalent. They measure the variations in the distances between the grooves and ridges of the fingerprint. Other methods rely on infrared (thermal) imaging, and pressure detection.  These methods all have their own drawbacks. Capacitance sensors, for example, work unreliably when the fingers are moist, while infrared sensors are affected by simply having cold fingers.

Other types of biometric identification mechanisms being explored include vascular biometrics that rely on subcutaneous blood vessel structure, and dynamic – or behavioural – biometrics. These include generally voice or electronic signature recognition. For firearms, researchers at the New Jersey Institute of Technology have developed a system called Dynamic Grip Recognition. It’s based on demonstrable changes over time in the pressure pattern created on the grip of a handgun that are individual to the user.

Over the last two decades advancements in two fields have made “smart guns” a reality. Advances in microprocessing – both processing power and ruggedness – have made increasingly more sophisticated systems possible. On the other hand, sensor reliability has also dramatically increased. The major hurdle to overcome now is a cultural one. With the public being more understanding of the need to ensure firearms are used in the right hands, it too might be overcome soon enough.