Making a good elevator control is difficult without some additional sensors. On modern elevators, there are amongst others sensors that tell the elevator on which floor it is, where to slow down and where to pull the break (or actually: release the brake as it's spring activated). I would not rely on counting steps as you can't tell how much the hoisting wire contracts or expands and after a power failure you would need to make some sort of 'reference run' to know where you are.

I can tell you a little story about a badly designed elevator control. The worst I have ever seen was on a container vessel I have sailed on in the 1980's. This vessel - and thus its elevator - was built in Poland. In its days, the vessel was "state of the art" in terms of automation; the memories I have from these days still come to good use when designing stuff as an example how not to do it.

Anyway, this elevator used only a single sensor to control everything: a multi-turn potentiometer driven by the hoist wire storage drum. The output signal was fed into a box full of analog comparators, the outputs of which were connected to a huge box of relays that controlled the indicators, motors, locks and brakes. Where the elevator would stop and open the doors was actually very unpredictable and was much dependant upon temperature, humidity, vibration, voltage fluctuations: you name it. So the only way to really control the thing was to push a button that would indicate the general direction you would like to go to, look through the doors window and monitor the hand-painted floor numbers passing by and then operate the emergency stop button at the right moment. After a couple of days you got the hang of it and it would be possible to stop the elevator level within one or two centimeters.

So if you don't want to use sensors: make sure you have a window in your doors and don't forget about the manual emergency stop !