This project relays a series of beeps in such a manner that the person whose device triggers the beeps can decode the information and know who is triggering a notification. This project recieves a 'fake notification' using the web UI. Of course for it to be useful this would need to be integrated into a modern phone OS or perhaps some sort of wearable. This was more of a psychology experiment than an actual project. After an hour of practice, I could listen to the noises generated and tell you which of the example situations triggered the audio.
This project won the "Rube Goldberg" category after the audience clicked tons of notifications and the device sounded like it was playing 8-bit music.
One of the requirements was PubNub integration. While PN is a great service, one which I work with all the time at work, this particular project didn't need it, so at the last second I added a gimmicky multiple cursor thing.
Another requirement was the use of an Electronic Imp. I used one for generating the tones via a Piezoelectric speaker, however a phone app or web interface could have replaced this.
You'll need to creage an Electric Imp account, register a device, attach a speaker to the appropriate pins, and upload the .nut files.