At the shared office our company used, you had to enter your phone number and a password at a kiosk every time you came in. Each entry took 30 seconds to a minute. Everyone on the team stood there several times a day.
So I built a device that presses the automatic door button on the inside of the door. Staff tap the card they always carry on a reader next to the door. An Arduino checks whether the card is registered, and a small servo motor presses the button and releases it. An unregistered card only gets a low beep, and the door stays shut. I didn’t touch the building’s door wiring.
The door is used all day. So if no one uses it for a long time, the reader restarts, and if the program freezes, it restarts itself within 2 seconds. To add a new staff card, you tap it on a separate registration tool, and it shows the number to register.
It wasn’t part of my job, but it cut entry time for everyone.