In a recent episode of the Mac Power Users I made an offhand remark how I thought it would be clever to use the Apple Watch to unlock my Mac. I received multiple emails from listeners telling me that this functionality effectively exists already with the application called Knock. I’ve been using Knock (iTunes) (website) now for a few weeks and am happy to report that those listeners were correct.

Knock is an iPhone application. It costs four dollars and once you install it, your iPhone becomes aware of when it gets near your Mac, even when it is locked. (You also need to download and install a utility app on your Mac found on their website.) Once you’ve got the system in place, when you get near your Mac, you will see a message on the lock screen that invites you to unlock by knocking twice on your phone. You can do this right in your pocket. For added fun, do this while pointing a toy sonic screwdriver at your Mac. The developer has a clever video that shows off this feature on their website.

After two weeks I’m convinced that this is more than a cute demo. I love unlocking my Mac simply by walking up to it and knocking on my pocket. I still think the Apple Watch could make this even easier but for now, you should check out Knock.