This is a well executed project and fun, poignant art piece: the Sigh Collector by Michael Kontopoulos. He writes:
These are instructions for building a home monitoring system that measures and ‘collects’ sighs. The result is a physical visualization of the amount of sighing, for personal use in a domestic environment.
The project is in two parts. The first part is a stationary unit, which inflates a large red air bladder upon receiving the appropriate signal. The second part is a mobile unit, worn by the user, which monitors breathing (via a chest strap) and communicates a signal to the stationary unit wirelessly when a sigh is detected.