I had a chance to test the viability of the project on a recent event. For this i produced 20 devices. Since i used an existing main board - they were a bit bigger than expected, but anyways it was nice to evaluate it. This is how the devices look like. There is a button and an RGB LED. The simple scenario I used was to let the participants connect the device to a HANA Clout Platform IOT Service and make use of the Button to trigger events, the LED to be controlled via a Web Application, and report the temperature online.
It is all configured by connecting the device via USB to a computer and then using a Chrome Application to setup all necessary stuff.
Next step for me is to build more examples also using other platforms like Thingspeak, Beebotte, Ubidots, etc.