What distinguishes a 'smart gun' from others?

 

Any time a toddler mistakenly shoots a friend or family member, a teen kills himself with a bullet, or a gunman commits a mass shooting. The topic of "smart gun" technology comes up in conversation. The idea stems from a 1995 report by the National Institute of Justice (NIJ), which proposed a technology-based solution to minimize the number of police officers killed in gun grabs by assailants. President Barack Obama's latest message on gun violence contained concrete guidance on federal actions to encourage the implementation and commercialization of electronic gun-safety systems.

The word "smart gun" has become a catch-all for all types of electronic personalized safety technology in the mainstream press. The aim is to ensure that its registered owner can only shoot a gun. However, the various situations in which a gun might be fired improperly necessitate radically different safety mechanisms. We provide the safest and the best gun safes for your smart guns.

A typical door lock metaphor is a helpful way to think about the different technical approaches. The key serves as a unique identifier for each person. The authenticator is the pin tumblers, which know the key inside the lock. The latch also acts as a block. All electronic gun-safety systems must recognize registered shooters, authenticate their credentials, and then release the block on the firing mechanism.

The performance constraints of the application environment and the physical constraints of the weapon dictate how certain needs are met. These distinctions result in distinct branches on the personalized-weapons technology family tree.

Can you hear me now, proximity sensors?

One set of solutions can be traced back to a National Institute of Justice study aimed at preventing police guns from being taken away during a close-quarters battle. It proposed using Radio Frequency Identification to create a token-based proximity sensor (RFID). Starting with Colt's 1996 pistol, a range of working RFID prototype weapons has been demonstrated, including Triggersmart, M-2000, and the Armatix iP1.

A consumer wears a passive RFID tag, similar to those embedded in goods to deter shoplifting, in the form of a badge, wristband, or ring. It's the "token," and in the front door metaphor, it's the key. It can be duplicated or exchanged in the same way that a physical key can. It is the possession of the token, not the identity of the token holder, that is essential.

The gun includes a wireless RFID reader that acts as an authenticator. It sends a signal to the RFID tag, causing it to respond with an embedded code. If a match is found, the electromechanical components unblock the weapon firing mechanism, and the gun resumes normal operation. The response time of these devices varies depending on the electromechanical components used in the blocking system (for example, servomotors, solenoids, and shape memory metals). Still, it is usually less than half a second. The gun is designed to stay active as long as there is a signal connection or, in some cases, as long as pressure sensors sense the gun is being held.

If the tag is too far away from the transmitter for it to self-activate and react, it's like losing your front door key: the gun remains locked. For example, the Armatix iP1 specifies a 15-inch range. If you try to spoof the transponder with a signal that doesn't contain the unique code, it's like trying to use the wrong key: it fits in the slot but won't turn because it is tumbler don't match, and the gun stays locked down.

In the upper photo, the RFID-type system of the gun is locked. The weapon is ready to fire in the inset, with the firing mechanism no longer blocked, and a user's tag (in the form of a ring) is close enough. CC BY-ND iGun Technology Corp

Various designs obstruct the mechanical firing mechanism in various locations, ranging from the trigger bar to the firing pin. Different technologies, such as solenoid actuators, shape memory alloy-based parts, and even electronic firing systems, can be used as a deadbolt to be released when an authentication device is received. The specifics are proprietary to each product on the market and represent design trade-offs in power consumption, component free space, and response time.

During a close-quarters confrontation, the proximity of the gun to the token is not an utter determinant of rightful ownership. However, the technology is simple to use, allows for quick weapon sharing among authorized users (i.e., partners), and reliably disables a weapon if the officer is overpowered and the duty weapon is taken.

Can I recognize you by your biometrics?

In the house, the advantages of a token-based scheme in a street experience become a liability. The approach's effectiveness depends entirely on the token's owner protecting it so that refused users cannot access it. Guns used for home protection, on the other hand, are more likely to keep the token and weapon together to avoid any delays in the event of an attack. It can be fired by someone who has both the token and the weapon.

The second set of innovations arose in reaction to child-safe handgun legislation passed in New Jersey and Maryland in the early 2000s, which was intended to discourage the illegal use of personal firearms kept at home. Physical tokens are no longer needed for biometric authentication systems. Instead, any approved user's observable physical characteristic becomes the secret. It cannot be copied, counterfeited, or otherwise transmitted without permission.

Fingerprints have been the most common feature used in biometric systems to date. Fingerprint detection is a primary mode of protection in Kodiak Arms Intelligent and Safe Gun Technology's retrofit for rifles. If the fingerprint is the secret, the sensor and pattern matching software is the pin tumblers in these weapons that perform the authentication.

Capacitance imaging of the fingerprint is the most commonly used sensor technology. The difference in distance between the finger's ridges and grooves and the sensor plate produces a distribution of electrical charge storage (capacitance) that can be calculated in the sensor's array of conductor plates. Some fingerprint sensors use pressure sensing to produce a digital pattern that represents the print, while others use infrared (thermal) imaging.

The sensor software must be trained to store appropriate patterns that can reflect multiple approved users' fingers or different fingers from a single user. Any pattern that does not fit within a certain tolerance is then rejected. The sensor's resolution, the extent and orientation of the exposed digit, and physical factors that can interfere with the mapping all affect the authentication process's reliability. Moisture on the finger, for example, can fool a capacitive detector; cold fingers can make thermal imaging less reliable; and dirt, paint, or gloves can mask the fingerprint beyond recognition.