title: iOS: detect app users nearby
body: <p>I want to build and app which can detect other iPhones with my app within 65 feet range. As I understand I have the following choices:</p>
  
  <ol>
  <li><p>Use Bluetooth to check periodically whether there is device with my app in the range. Send list of found devices to the server. The problem here is battery consumption. Is it true that Bluetooth will be disabled after some period of time automatically?</p></li>
  <li><p>Can I use BLE technology for this purpose? If so, do you know what devices support BLE?</p></li>
  </ol>
  
  <p>What is the best option on your opinion? Did I miss some other option?</p>
  
  <p>Thanks</p>
  
  <p><strong>UPDATE</strong>
  I plan to run search every 20 seconds or even more often.</p>