Anil Madhavapeddy

Using visual tags to bypass Bluetooth device discovery / Jan 2005

While designing Spotcodes, we realised that visual tags are a much better mechanism to advertise security keys to users instead of the error prone and much more difficult to use Bluetooth device discovery protocol. We duly implemented the direct system, and conducted a user study with Eleanor Toye Scott who was down the corridor working with the HCI group in the Computer Lab. The resulting journal paper on our SpotCode visual tag login system is a fun blend of systems and human factors.

We do not believe that printed tags are competing with RFID and NFC for the prize of "universally accepted connection establishment technology". Instead we observe that each offers complementary tradeoffs in terms of cost, data capacity, interaction distance, client-device compatibility and visibility. We predict that all three of these technologies will ultimately be integrated into mobile applications to provide consumers with the flexibility and functionality they require.

(Update: and indeed, two decades on in 2025, this has played out pretty accurately. It is common now to use QRCodes to access services, and wireless scanning is a relatively rare thing to do but still available.)