Utilizing beacons

The previous section introduced the GATT profile as a way for Bluetooth LE devices to communicate once connected. But BLE devices can also send data without being connected by using the Generic Access Profile (GAP) in "advertising" mode. In this mode, data is sent out in specially formatted data packets on a periodic basis, thus acting as a beacon for any device that is listening.

There are currently three general beacon formats:

• iBeacon: Apple was the first to create a beacon format; it is simple and robust.
• AltBeacon: This open format, created by Radius Networks, is very similar to iBeacon but has a little more data available and is not company-specific.
• EddyStone: Google created this open source, cross-platform format that defines different types of frames for a variety of applications; it is part of their Physical Web initiative.

To use beacons in your Delphi app, you may be thinking that you have to learn about the underlying...