…Breathing can be useful?

Breath Powered USB Charger

Quit wasting your breath and put it to good use. This interesting looking contraption is actually a USB charger that is powered by the expanding and contracting of your body as you breathe. With a few scavenged parts from an old CD-ROM drive, a simple electronic circuit, and rubber bands, “you will soon be huffing and puffing your way to fully-charged pseudo-useful electronic gadget nirvana”.

[Instructables – Breath Powered USB Charger]

[Via: MAKE: Blog]