Hardware to connect wired contact switches


what would be good hardware to connect about 25 wired contact switches to the Openhab and get their status. These are contact switches on my doors and windows, so I want to detect if the window is closed/open.

Currently they are wired to a Nikobus binary input modules (05-206) but this way it will only trigger changes (from open to close). There is no way to read or get the absolute state in Openhab. So there is a risk of getting out of synch if a state change is missed. That’s why I want to re-connect them to another Openhab input device that is able to read the open-close status and not just trigger the status change.

Any suggestions on what to use best or experiences.

How about connecting the contacts to an Arduino Mega (up to 54 channels) and to communicate between your OH server and the Arduino via serial port?