Users are grouped according to their group names session ID in iOS development terms).
By default, all devices from our group share the same group name of "MooresLab
".
Other groups attending the conference can use their own group names to establish intra-group messaging.
A user can generate generic messages or ones specific to a poster.
In either case, these messages are intended for all other group members.
To do this, the app uses the Bluetooth radio on the iPhone to achieve short-range wireless communication. Since it does not rely on any infrastructure at the conference venue, such as Wi-Fi access points or cellular base-stations, it can function in a wider scope of settings. The Bluetooth radio on-board of the iPad has a transmission range of up to 100 meters in a not-so-"noisy" environment. At conference venues, however, its range will be a fraction of that. In general, two devices can be out of range of each other frequently, depending on where the users are and how they move. Thus, a device will "mechanically" transport messages from one location to another as its user moves around. When the app detects other group members within range, it swaps messages with them. As a result, a message propagates among devices belonging to the same group until it reaches everybody. Apparently, messages delivered as such are not "instant".