Usually based on Bluetooth Low Energy (or Bluetooth Smart), beacons are basically broadcast transmitters of individual IDs, so that an intelligent device (typically a mobile phone) can react on known IDs when detected.
The beacon’s ID and possible sensor information etc is sent continuously at an interval of 1/10th of a second or slower, depending on what responsiveness is needed for a certain situation.
The power level of the BLE radio can usually also be controlled, to provide a trade-off between distance and battery drain.
Not all beacons are battery-powered though. There are USB and power supply variants available as well.
In theory BLE can reach 100 meters, but is very sensitive to obstructions, so it’s enough with some metal or water in between the beacon and the detecting device to lower that distance considerably. Even on full power, don’t expect more than 20 meters or so.
There are numerous beacon formats being available, essentially differing in what data is being sent:
- iBeacon: Apple’s pioneering variant of beacon, sending UUID, major ID and minor ID, that can all be configured to ones liking
- Eddystone: Google’s variant of beacon, providing separate packets with different uses: UID (similar to iBeacon), URL (supported by Chrome and soon Android), TLM (beacon status)
- AltBeacon: An open-source format, backwards compatible with iBeacon
As the focus is access and “interpretation” via mobile phones, uses are typically in situations where people move around, e.g. in retail, exhibits, conferences, museums etc.
Abiro provides support for iBeacon and Eddystone-URL (as of yet) in CliqTags. On the site are described more about beacons and uses thereof.