San Francisco Airport is testing out location-aware beacons to help visually-impaired people navigate around one of its newest terminals, a program it could roll out to the rest of the airport if successful. An early version of the system was shown off to press today for use on Apple iOS devices, though SFO also plans to make it available for Android users and eventually expand the system to serve up information for those who can see.

The beacons are coming from an indoor positioning company Indoo.rs and have been installed throughout the terminal. Each beacon will connect to a smartphone app to pop up with information when a user gets within range. For the visually impaired, the system uses Apple's Voiceover technology to read out points of interest as they come on screen, though an early version of the app also gives people visual cues for how to navigate to locations from a directory that can be sorted. That means you could tell it to help you find the nearest power outlet to juice your gear, or the nearest coffee shops to recharge your body.

Each beacon, which is about the size of a bottle cap, costs about $20 and runs off battery power to push out signals using Bluetooth low energy. Indoo.rs CEO Hannes Stiebitzhofer says the beacons will last for four years before the batteries need to be replaced, and that the company installed about 300 of them around the terminal. Looking around, you can hardly see them since they're above eye level and many match the color of what they've been adhered to.

These beacons will run for four years

SFO's pilot follows another from Virgin Atlantic, which announced in May that it's testing Apple's iBeacon in London's Heathrow airport. The company partnered with Estimote (an Indoo.rs competitor) to install the beacon hardware around its part of the terminal, and beam notifications to passengers. That includes when they come near its upper class wing and club areas, as well as the security area to pull up whatever boarding pass is stored, though the system is designed primarily for people without visual disabilities.

Location beacons are in their infancy in terms of adoption, but are beginning to show up in retail spaces, museums, movie theaters, and some sports venues. Retailers like Macy's, American Eagle, and Lord & Taylor are testing the technology, along with the Ruben's House museum in Antwerp, Belgium, which is using it to display information about works of art. Major League Baseball installed iBeacons in 28 of its ballparks last year, and is in the process of adding them to others to give attendees point-of-interest information, and push out information about local park concessions. Britain's Odeon Cinemas is testing the same thing at some of its theaters to push out information about movies and get people to go buy popcorn.

SFO and Indoo.rs say they plan to continue testing this system over the next month with a live version of the site, and public availability of the software in the fall.