What’s the difference between a tag and a beacon?


What’s the difference between a tag and a beacon?

The rapid evolution of Bluetooth technology has left some people a little confused about how this radio system is implemented in tags and beacons.

You could argue that the idea of radio tagging emerged with short range passive RFID tags. These provided a simple code in response to the proximity of a scanner, which also provided the power for the transfer. These scanners were largely industrial units, but as smartphones became more popular, the idea of smart posters and signs emerged. These displays had an embedded RFID tag so that users could walk up to the poster or sign and access extra information via an associated app that connected to the Internet through the phone. The passive tags didn’t require a battery and the code could allow the app to access data such as real time travel information at a bus stop or download a video trailer for a movie poster.

The drawback of these displays was the need for the phone to be close to initiate the link. This need for a close connection works well for application such as London’s Oystercard to pay for travel, and for contactless credit card and debit card payments, but not for broader applications.

So the Bluetooth beacon emerged. Using the latest Bluetooth low energy protocols, a beacon works in a similar way but broadcasting a code over a range of 30 to 50m. This code can be picked up by a Bluetooth-enabled smartphone and used to trigger an app that has already been downloaded. This app can be an offer in the shop that you are walking past, an invitation to a special event, that movie trailer from a poster on the other side of the road, the temperature, or even an augmented reality overlay. A good example of the operation of beacons is in museums to provide more information about exhibits, using the code from that exhibit to download more data, from pictures to videos.

What it does not do is support a two way link back to the beacon as all the connectivity is through the smartphone. This means that a Beacon can be easily installed, powered either by a mains supply by plugging into a convenient socket, a battery-backed module stuck on a wall or in a cabinet or a solar-powered module that is self-sufficient in power.

The Beacon is part of the fixed infrastructure, providing a broadcast, one way tool that provides a trigger code that is used by an app to provide additional data, often downloaded by the smartphone. As a result, privacy and data issues reside in the app, even though actions are triggered by presence of the beacon.

The latest version of the technology takes this a step further.

The reducing size and power consumption of the latest Bluetooth low energy implementations is opening up a new class of device, the Bluetooth Tag. This acts as a Beacon, but adds two way communication between the tag and the smartphone. This can be used in a number of ways.

The main use for a tag is to locate an item. The tag, powered by a small coin cell, can be attached to an item, whether keys, a wallet, luggage or even a pet. This requires the two way link to a smartphone to pair the tag and establish ‘ownership’. Once paired, it sends out a code regularly. If that code is not received by the smartphone, an alarm is triggered so say that the item has moved out of range. Alternatively the smartphone can send a code to light up an LED or trigger an alarm to locate the tag. But this code has wider applications, as any other user of the app can receive it. So if another user receives the code from your tag, the code triggers the upload of current GPS location data from that phone to be uploaded to a crowdsourced database. So if your luggage goes missing with a tag attached, then its location can be shown on that crowdsourced map via other users of the same app. This is a hugely powerful capability that requires the two way pairing.

But the tag is more than a beacon. One tag maker, Tile, is developing partnerships with a wide range of different organisations around the technology. For example, if the flight attendant and pilot have the app on their phones, if you forget something in the plane you can be alerted before you leave or in the terminal building. You could also use it to track your luggage through the smartphones of other users.

Similarly if employees of a theme park have the app on their phones they can crowdsource the location of a lost child via a tag. This provides a flexible, mobile infrastructure which makes it very powerful.

Of course things are not quite that simple. Beacon makers do include a two way Bluetooth low energy communication capability in their devices so that the code can be changed or the beacon firmware can be re-programmed to add new functions. But it is not available to the general public, and the unidirectional beacon remains a powerful part of a fixed broadcast infrastructure.

The evolution of beacons and tags is opening up a wide range of new applications. As the size and power consumption of the latest Bluetooth single chip transceivers drops with innovative chip designs, so these devices can be used in many new places in various ways. While the underlying technology is the same, the way beacons and tags are used is quite different, and understanding those differences leads to powerful new applications for users.