This iPhone-app-slash-Mac-utility came out a few weeks ago and it’s quite spectacular. Your iPhone and Mac pair up via the low-energy Bluetooth 4, and then when you come into proximity of your Mac and see the lock screen, you just knock twice on your phone. And presto! Your Mac is unlocked.
(Remember when we had to type our user passwords in like animals?)
I’ve been using Knock since it first came out, and it works right away about 95% of the time. Sometimes it takes a few seconds for the iPhone and Mac to pair up before I can knock to unlock. And as for the drain on my iPhone’s battery, it’s been negligible.
Update: Since posting this link last night I’ve received quite a bit of comments from folks on Twitter who haven’t had as much luck with the app that I have. Apparently it can be hit and miss, and some folks frequently have to toggle bluetooth of and off on their iPhone to get Knock to re-connect their Mac and find that it’s just easier and faster to type their password in. So, alas, I guess your milage may vary.