<p>In general, this disclosure describes techniques for unlocking certain functionality of a mobile computing device upon wirelessly detecting that an external device is in relatively close proximity to the mobile computing device. One example method comprises: providing a phone application and a second, different application; initiating a first mode of operation when the mobile computing device becomes locked; prohibiting user access to the second application during the first mode of operation when the mobile computing device fails to wirelessly detect a presence of an external device; and initiating a second mode of operation when the mobile computing device wirelessly detects the presence of the external device and when the mobile computing device has received user input specifying an access password, wherein the mobile computing device allows complete user access to both the phone application and the second application during the second mode of operation.</p>
