I'd like to convert my stupid door lock into a smart one.
I already have a gear for the lock knob. Now I'd like to design a gear decoupling system that will be connected between the knob and the motor so that the door can be opened with a key when the motor is not running. I thought about using the electromagnetic clutch, but they seem to be not very popular because I could find only used ones from printers at an affordable price. I don't even know how to power them. I want to use something more accessible than this particular electro-clutch.
My second idea is to use a solenoid or servo to connect the gear racks together. It would be also cool if it was possible to design this using only mechanical parts. Does anyone know of any examples of projects with such a solution that I could take a look at? What are the ways to solve this problem?