Apple’s own description of iBeacons is "a new class of low-powered, low-cost
transmitters that can notify nearby iOS devices of their presence^6 ". This can be
read as implying that the beacons notify the iOS device of its location. This is
a good enough model but it skims over some complexity.
What actually happens is: the beacon broadcasts a unique ID. The iOS device
detects the ID, and looks up its location in an online database. It notes its own
position by its proximity to the beacon. In looking up the beacon, it informs
Apple of its location, and Apple then send the push notification.
9- 11: iBeacons diagram: what the user needs to know, and what’s actually
happening
UX researchers at Ericsson have suggested that it is particularly difficult for
users to understand networks of devices. Their informal research indicated that
users currently think of connections between devices as being ‘invisible
wires’. As Ann Light, co-author of chapter 15, puts it: “Most people are
disposed to think of things, not links; of nodes rather than relations”^7. But this
way of understanding is not helpful in making sense of complex networks with
many interconnections and interdependencies^8. To understand a system,
users must understand the links as well as the nodes.
In 1983, the HCI specialist Larry Tesler (then at Apple) proposed the Law of
Conservation of Complexity. Interviewed in Dan Saffer’s book ‘Designing
Interactions’, Tesler says: “I postulated that every application must have an
inherent amount of irreducible complexity. The only question is who will have
to deal with it^9 .” His point was that shielding users from complexity would
involve extra work from designers and developers.
(^6) https://developer.apple.com/ios7/, which now redirects to iOS8, original text retrieved
via http://en.wikipedia.org/wiki/IBeacon#cite_note-5
(^7) In conversation.
(^8) Joakim Formo, The Internet of Things for Mere Mortals,
http://www.ericsson.com/uxblog/2012/04/the-internet-of-things-for-mere-mortals/
(^9) Dan Saffer, Designing for interaction, 2006, New Riders. Larry Tesler interview
available at http://www.designingforinteraction.com/tesler.html