To activate / deactivate the alarm you can additionally define alarm keys. Currently, only Homematic IP buttons and hand transmitters are available for this function, since their communication protocol is encrypted and so the signal is protected against a replay attack.

To create a new alarm key, go to Settings → Alarm. Select absence or presence mode and tap “Keys”. Tap “Add” and select the device and the buttons with which the alarm should be activated or deactivated. Finally save the settings.