We've recently launched an open source IoT Cookbook which offers step-by-step recipes for IoT components and applications. As an example, there is an alarm application which can use one or more Arduino Yuns with accelerometers for triggering the alarm and buttons and LEDs for control and feedback about the alarm state (as well as having a browser frontend).
Everything is connected through the open-source WAMP protocol, which enables all components to communicate as equals using PubSub and routed RPCs (i.e. any component can call procedures on any other component). Since this is cross-language and cross-platform, applications can encompass multiple devices and device classes.
For the Arduino Yun, there are components which send accelerometer, tilt sensor, ambient light sensor, button or potentiometer data, as well as one for controlling lights. These components can easily be adapted for other modules - and combined with other devices. The alarm application has (optional) components using a Raspberry Pi (camera, text-to-speech output) and Tessel (accelerometer, camera).
So take a look and experiment a bit! Everything is open source - and your feedback and contributions are highly welcome!
Greetings to all,
(from the WAMP & Crossbar.io team)