Source: Nick Sutrich / Android Central For years, the best smart locks have been trying to get rid of keys, but the experience often falls short of the simplicity of a key. Sure, you could use the PIN pad to unlock the door, but, personally, inputting a PIN always feels like an easy way for someone to gain easy access by watching you tap (or looking at the fingerprints on that shiny keypad). Smartphone entry is a great alternative — especially when locks like the August Wi-Fi Smart Lock will automatically unlock when you're in range — but that, of course, requires you to have your phone on your person, making it no better than a key that can be left in the house accidentally.