If you've lived on this planet long enough, you've probably had that moment where you thought you'd closed the door on your way out, only to find out that it didn't quite shut. But how are you supposed to know if no one's at home to tell you, and even many smart locks won't fill in the gap? August Home thinks it has the answer. It's introducing two new locks, a lower-cost August Smart Lock (shown at center) and the August Smart Lock Pro (at left), that include a sensor to determine whether or not the door is really closed. If it's ajar and the deadbolt didn't engage, you can find out through your phone instead of having to return home.