Bluetooth, RFID, or QR code: which event badge technology fits which event?

A QR code badge is a printed identity. The code holds an identifier. When someone scans it, the system knows who showed up, where, and at what time. That is all it does, and it is already a lot. Its strength is simplicity. No electronics, no battery, no pairing, no distribution logistics. It works with a phone camera, which means it works with hardware everyone already has in their pocket. It reprints in thirty seconds at the registration desk when an attendee forgets theirs, and it goes in the trash at the end of the event without a second thought. Its limit is the gesture. A QR code produces data only when someone decides to scan it. Between two scans, nothing happens. The badge does not know where its wearer is, who they walk past, or how long they stayed in a room. Every piece of information costs a gesture: a line, a staff member, a raised phone. At a 2,000-person conference, adding scan points means adding lines. So a QR code answers one question very well, and only one: who passed through this checkpoint?

RFID moves the intelligence out of the badge and into the venue. The badge carries a chip. The venue carries readers: entry gates, room pedestals, overhead antennas, floor mats. When the wearer comes within range of a reader, the passage is recorded without any action on their part. This is the technology of large flows. An RFID gate clears an entry line far faster than manual scanning, and it produces reliable data on the thing it cares about: passages. How many people entered the keynote, when the peak formed, which room emptied after the break, which breakout filled up. Its limits are physical and logistical. A passive RFID badge only speaks in front of a reader, so the map of your data looks exactly like the map of your readers. Whatever happens between two readers is invisible. Active RFID badges exist, powered by a battery, with longer range — but then you are back to an electronic object that has to be handed out and collected. More to the point, that map of readers has to be installed. Pick the locations, power them, test them, tear them down. In a venue you do not know, with a few hours of setup time, that is a project of its own: a technical contact at the venue, a floor plan, a dry run. It is doable. It is the norm at very large trade shows. It is not free of consequences. RFID answers this very well: how many people came through here, and when? It says nothing about who met whom.

Bluetooth Low Energy (BLE) measures neither a point-in-time identity nor a passage. It measures proximity, continuously. A BLE badge emits a short signal at regular intervals. Any device in range hears it, and the strength of the received signal gives an idea of the distance. The difference is in kind, not degree. The first two technologies observe fixed points. BLE observes relationships. Two badges that stay side by side for eight minutes are not a passage. They are a conversation. BLE is the only one of the three that can say "these two people met" rather than "these two people attended." One common confusion is worth clearing up here, because two very different architectures hide behind the same word. In the first, fixed beacons are installed in the venue, and those beacons listen for badges or phones. You get the resolution of BLE, but you inherit the logistics of RFID: placement, power, calibration, teardown. In the second, the badge itself is the beacon. It is detected by the phones of other attendees, and there is nothing to install in the venue. That is the architecture of the Smart Ruby badge, and it is why the same setup can follow a roadshow from city to city with no site survey. BLE answers this: who crossed paths with whom, where, and for how long?

QR code — What it measures: an identity, at the moment of the scan. — What it requires from the venue: nothing, beyond someone or something to scan. — What it asks of the attendee: a gesture, every time. — What it cannot do: trace a path, detect a meeting. — Where it fits: access control, attendance sheets, breakout check-in. Passive RFID — What it measures: passages past readers. — What it requires from the venue: a reader infrastructure, installed and tested on site. — What it asks of the attendee: nothing. — What it cannot do: tell you who talked to whom. — Where it fits: very large flows, multiple entrances, room counting. Bluetooth (BLE) with fixed beacons in the venue — What it measures: positions and proximity, inside the covered zones. — What it requires from the venue: beacons to place and calibrate. — What it asks of the attendee: the app, with Bluetooth on. — What it cannot do: work outside the covered zones. — Where it fits: a single, controlled venue, reused edition after edition. Bluetooth (BLE) where the badge is the beacon — What it measures: proximity between attendees, everywhere they go. — What it requires from the venue: nothing. — What it asks of the attendee: the app, with Bluetooth on. — What it cannot do: control access, or work without the app. — Where it fits: networking, trade shows, corporate events, business clubs, traveling events.

Let us be straightforward: Bluetooth is not the right answer everywhere, and it has flaws no vendor can erase. The first is physical. Distance is inferred from signal strength, and that strength is affected by anything between the two badges: a body, a partition wall, a metal structure, a dense crowd. Under normal conditions the reading is fine-grained, accurate to within a meter. In a packed hall or behind a load-bearing wall, it degrades. BLE gives you estimated proximity, not centimeter-level map coordinates. A vendor promising centimeters is selling you an idea of BLE, not BLE. The second is human. The badge broadcasts, but something has to hear it. Detection relies on attendees’ phones, which means the app has to be installed and Bluetooth has to be on. An attendee who does not install the app sees nothing and is seen by no one. That is why app adoption matters more than the badge technology itself. Across our events equipped with badges, we measure roughly 85% download and usage (internal measurement, 2018), and at a SPIE seminar in 2018, 94% of attendees had downloaded the app. Below a certain threshold, a proximity badge stops being worth it. Check that number before the event, not after. The third is hardware. A BLE badge is an electronic object. It has a battery, it gets handed out at the desk, it gets collected on the way out. It does not reprint in thirty seconds like a sheet of paper. We offer these badges as rentals, which shifts the problem without removing it: distribution and return still have to be managed. Finally, BLE does not replace access control. It does not decide who is allowed in, and that is not its job. Attendee check-in happens in the app.

Internal meeting, corporate event, incentive trip. The challenge is not flow, it is mixing: getting teams that never cross paths to actually talk within two days. A QR code only handles the attendance sheet. RFID is overkill. The BLE badge is the most useful option here, because it is the only one that can tell you the next morning whether the mixing happened. Trade show. Both logics coexist. Access control and counting belong to QR codes or RFID. Connecting a visitor with the right exhibitor belongs to proximity. At a trade show the question is not "how many people came" but "how many good conversations happened," and that question has only one technical answer. Scientific or medical conference. RFID still rules keynote entrances and session counting. BLE is a useful addition when the conference has a genuine meeting agenda: committees, learned societies, industry partners. Business club, industry network. These are communities that gather several times a year, often in different venues. Fixed infrastructure is beside the point here. A badge that travels with the setup is not. Traveling event, roadshow. The deciding factor is the site survey. Anything that requires installation in the venue has to be repeated in every city. Anything that fits in a case does not. And in every case, one detail that matters: for us, the badge is an option. The app works without it, with the agenda, messaging, meetings, live questions, polls, and offline mode. The badge adds proximity. It is not a precondition for the event.

Smart Ruby is a Bluetooth beacon worn on a lanyard. It geolocates the other attendees to within a meter, and it is the attendees’ phones that detect it. There is no infrastructure to install in the venue. It is available as a rental, and it stays optional: an event works with or without it. That positioning has a practical consequence people underestimate. Because nothing is mounted on the walls, there is no site survey, no floor plan, no negotiation with the venue, no teardown at midnight. The setup follows the event, including when the event changes cities. It also has a consequence for the data. What gets measured is not a passage through a gate. It is proximity between two people. That is where matchmaking connections, meeting suggestions, and the networking statistics in the organizer dashboard come from. Across 100+ events equipped, that adds up to more than 12,000 accepted matchmaking connections (V1 export, December 2, 2021). And since we are being candid about limits: this badge does not handle access control, does not swap contact records on contact, and is useless if the app is not installed.

A proximity badge produces personal data. Three questions are enough to evaluate any vendor seriously, whatever the technology. Where is the data hosted? For us, in the European Union. That is a verifiable answer, unlike "our servers are secure." Who has access, and for what? The organizer reviews the data in the organizer dashboard and exports it to Excel or PDF. A documented REST API is available for organizations that want to plug in their own tools. What happens to the data after the event? That is the question nobody asks and everybody should — including of us. One piece of method: ask for those three answers in writing, before you sign. A vendor who answers them plainly tells you more about their standards than any spec sheet.

— The Smart Ruby badge in detail: /badges — App features: /features — The organizer dashboard: /organizer-dashboard — Trade shows and exhibitions: /trade-shows — Conferences: /conferences — Corporate events: /corporate-events — Business clubs and networks: /business-clubs — Case studies: /case-studies