Control access as it suits your needs
Access control is easy with one application on your mobile. You can use a simple keycard to enter any door or remotely control the access. You can also enter thanks to location-based trigger, but it's up to you to choose what is the easiest way, for you.
You can give different permissions to different people. Pierre is adjusted to know who has access where, and according to that people can get in. Every access is logged so you can follow it through the application.