Physical barriers against real-world intruders (as opposed to the cyberspace kind) is largely not nerdy. It is doors, locks, bars and stuff like that.
There is scope to add nerdy stuff in the form of DYI electronic locks and stuff like that.
Sites such as hackaday have run many articles on electronic locks of one type or another.
We don't want to carry a kilo of keys everywhere and spend half an hour locking and unlocking stuff every time we leave the house - so a central locking for home in is order.
A word or two of caution.
Making the place too secure could make it a death trap. You have to be very mindful of being able to exit in case of emergency. You also must be sure you can't accidentally trap yourself (or others).