I live with a person with lock anxiety, and I'm looking for a DIY solution. I already have an alarm system that beeps if a certain door is closed, but how can I also make sure it's completely locked?
The key word is "completely". The door already has a deadlatch and a dummy knob on the outside, so it already locks people out. However, there's a little knob that locks the inner handle in place and prevents jimmying. Since it doesn't automatically engage, it elicits frequent checking and rechecking.
I've considered some possible solutions:
Just remove the little knob to take away the uncertainty. That comes close, but I would prefer to be able to state that the door has been made more secure in case they ask for details.
Use an electronic deadbolt with timer functionality. This seems needlessly complex and expensive, and requires batteries.
Screw on a gate latch or similar. These are too flimsy and only meant for holding a gate closed, not to lock a door.
To clarify: making sure the door is closed is a non-problem due to the alarm. Door closers and spring hinges don't matter. The door also does not need to allow slamming it shut: it's fine if you have to push/press/hold/twist something to close it.
Is there such a thing as regular deadbolt but that engages automatically via a spring for example? So that you have to twist it back to close the door, but when the door is closed, it's 100% engaged?