If the door does not open
You have to reset the Arduino using the physical Reset Button (See added image), the small black button.
How change who gets in and who not
1. You can open the door using the webpage where all the people who are Mediamatic user of google calendar can log in, using the same info as you use to get to your Mediamatic google calendar. There is no separate way of managing this list.
2. You can call the door using your phone. Phone numbers can be added or removed from the list.
Marco Wessel knows how to do this.
The Arduino hardware system for connecting the phone system to the door system is in the server room.
This system is developed by former employee Marco Wessel who now works at Driebit. You can contact him best trough sms to (nul)(zes) 52 61 44 03
Later Saro Van Cleynenbreugel moved the module to the 'server room' into the former Nedap power unit (used for the former RFID door opening system).
If you open this box you can find the Arduino running the software for the internet door opening.
Please make sure there's always a plastic wrapper around the module, to prohibit the whole thing from short circuiting.