We’ve been working on a ESP8266-based motion sensor using PIR sensor, with a motor port to control a servo — the idea is that this can sense a person standing in front of the door and that in turn triggers the motion of a physical bell. It can also send notifications remotely, or you can remotely trigger the bell to ring. It’s along the lines of OpenAlarm, but perhaps the sensors you have in mind are different.
Speaking of door/window sensors — Jeff Lawrence’s improved OpenGarage firmware:
supports connecting a simple switch sensor to OpenGarage (instead of using the built-in ultrasonic distance sensor). That may immediately address the need of a door/window sensor. We are in the process of merging his changes to the master branch.