A US app developer says it is testing a smartphone app that can help blind people find each other in public places. Smartphones are gaining use among blind people, and the People Finder can help with the frustrating task of locating blind friends in a public place by alerting a user by vibration and a sound alert when someone also running the app comes within 50 feet, the Sendero Group said. The two phones running the app communicate by Bluetooth, and the app can let users know how close they are by saying "near" or "cold" as they walk. Sendero head Mike May says his company has years of experience making accessible GPS solutions for blind pedestrians but that he long wanted to make a people-finding app. "As a blind person I'd love to be made aware of when somebody I know is nearby, so that I can meet with them," he told the BBC. "As a bonus, you will also be careful not to talk about someone if you know they might be in hearing distance." May said 100 blind people are testing the app, now in the prototype stage, and he is seeking funding for further development.