I would like to design a lock which will automatically open once someone is on a specific side of a door ("outside").
There are easy (software) and complicated (hardware) elements to take into account but one of the points which i do not know to approach is the side detection.
How is this typically done?
An example is my car which will let the door close only if the key is outside the car. If it is next to the car outside, the car will lock. A few centimeters in (the key touches the door from the inside) and it is not possible to lock the door anymore.