Visually-impaired travellers at San Francisco International Airport (SFO) are now being guided through terminals via Bluetooth Low Energy (BLE) beacons supplied by Indoo.rs. Some 500 devices have been placed at boarding gates, restaurants and power outlets to trigger audible calls on a passenger’s smartphone when in beacon range. “The prototype version will undergo additional testing and refinement before being released for use by the traveling public,” SFO says.