Most piezoelectric materials, which convert mechanical stress into electricity, are heavy and brittle ceramics. Now a team at Johns Hopkins University in Baltimore, Maryland, have made a flexible piezoelectric by combining silicone rubber with a polypropylene foam. Potential applications include foldable loudspeakers and lightweight devices that “scavenge” movement or sound to generate power.
Air-conditioning units could one day monitor activity in the home, turning themselves down if no one is in a room. Shwetak Patel at the Georgia Institute of Technology in Atlanta has developed an air-conditioning system with centralised pressure sensors which detect small air-flow disturbances caused by people…
