The Mercuy System is more than a tool to develop IoT applications, and it could be easily extended to any general purpose embedded project. Here is a video of a proximity lock developed using a BB01, an ultrasonic and a relay SB (plus an expansion quand and the development framework).
This device could be used as electronic lock with contactless activation or similar applications. Done this morning in a couple of minutes, exploiting the potentiality of the framework 🙂