My front door has a surface-mounted rim night latch, that auto-locks when you pull the door shut. Mostly I just slide the little bottom lever (right → left) to pop the latch, walk out and close the door and it locks itself.
I am planning to automate door unlocking without replacing it with a smart lock but through mechanical parts and unlocking the door on command through an app or something.
Below is a representation (Claude built it) of how I imagine it will work like.
Tentative Plan
I knew I would need a servo but Claude suggested to go for a linear servo which seems to be the best option for this. I’ll have to do some research on the stiffness and the travel distance etc. before I can narrow down on the best option.
To communicate remotely, I have spare ESP32 and an old Raspberry Pi 3. I will probably use an ESP32 as it’ll be smaller and easier to mount on the door.
I am not too sure of the power supply logistics TBH, can get a little messy to keep it more practical for day-to-day use.
Once I have things working, I’ll probably wrap it all up in a 3D printed housing.
I have not decided the mechanism to trigger unlock (some kind of scan vs app etc.), but that’s the easy part.