Al that Jaz

We just spent 72 straight hours putting together the tech behind a nifty installation for Al Jazeera English as part of the channel’s new brand campaign – its largest marketing push to-date – all under the strapline, Hear the Human Story.  
The installation at St Pancras, London, features 10 light boxes, each audio-enabled with a directional sound projection playing a story narrated by the subject of the photograph on display.  The clever bit, however, is the triggering system.
A microphone mounted on the side of each light box has to be picked up and pointed at the image, as if the user is interviewing its subject.  At this point, an inaudible signal played back through the directional speaker overhead is detected by the microphone, initiating the audible playback of the story, again through the directional sound projection.  How nifty is that?
The installation is live for two weeks, so please do check it out if you’re passing by.