RF-ID is the technology allowing a low-power or no-power chip to communicate wirelessly. Dongles in a car that pay tolls, credit-cards that can be charged without contact, and badges that open doors are all RF-ID applications.

RF-ID stands for Radio Frequency Identification and works by wirelessly transmitting what is essentially a barcode. There are two basic types: one that has a power source that is able to transmit much further and those without a power source, wirelessly powered by the unit that reads the codes. Non-powered RF-ID devices, including name badges and credit-cards, are more common. However, powered RF-ID devices — like the clickers that open car doors and serve as a key, or that pay tolls — have more uses. (But, as anybody who has ever lost a car remote knows, they are extremely expensive.)

The first crude RF-ID systems were invented by Nazis, who found that rolling their planes a certain way changed radio waves being reflected identifying them as Axis rather than Allied planes. The Allies built on that, developing a system the planes themselves transmitted, an early “friend-or-foe” device.

Researchers continued building on the systems, with the most widespread use being anti-theft devices that triggered a radio wave to beep, alerting a store something was being carried out. Despite the simplicity of the system, and that it dates back to the 1960s, this type of antitheft device remains in widespread use.

In 1973, British-born American immigrant Charles Walton patented a device to transmit serial numbers that unlock doors. Walton would go on to patent many more RF-ID devices and is generally considered the innovator of modern RF-ID systems.

The US government created a system in the 1970s to track nuclear materials, including nuclear weapons, by “buzzing” a transponder in a truck as it drove by. Scientists who developed it eventually left to form the first automatic toll payment system. Another US government agency, the Department of Agriculture, devised a passive non-battery operated system to track cows.

RF-ID technology continues to develop, with non-powered chips that operate at ever further distances. Animals, especially dogs, routinely have chips implanted under their skin to help locate an owner if they become lost. A small number of people have done the same. Although the technology for people and dogs is essentially the same, there are obvious ethical differences.

RF-ID chips are used in supply chains, to track boxes for example, but are typically too expensive to replace barcodes for ordinarily priced individual items. However, scientists continue working on the project with the goal of simply shopping and walking out of a store, with all items scanned automatically. In 2018, Amazon created a store called Amazon Go that uses cameras, sensors, and machine learning which functions this way. However, Amazon Go does not use RF-ID chips, which would increase the cost structure.

In the future, the use of RF-ID chips is likely to dwindle as cameras and similar “seeing” devices increase in power and decrease in price. The chips, no matter how inexpensive, will always cost more than printed barcodes which themselves may become obsolete as computers simply recognize items in much the same way that people do.