GOOD VIBES FOR TOUCH SCREENS
A touch-screen sensor that works like a flat-panel loudspeaker in reverse has been developed by British audio company NXT and US-based 3M.
Today鈥檚 touch-sensitive screens on PCs or PDAs work by sensing changes in an electric field caused by the pressure of the stylus or finger. But the NXT/3M panel 鈥渓istens鈥� for the vibrations caused by touch 鈥� using much simpler and potentially cheaper technology.
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NXT鈥檚 flat-panel speakers use peizoelectric transducers at the sides of a flat panel to flex it, creating sound waves that radiate into the air. The touch panel reverses this principle, using transducers at each corner to convert touch vibrations into electricity. When you press a virtual button on the screen, a microchip triangulates the time of arrival of the vibrations at the transducers to work out where on the screen 鈥� and therefore which button 鈥� you pressed.
The transparent panel would be mounted on top of an LCD display, and could be a few centimetres wide for a PDA or up to a metre wide in a whiteboard application. Usefully, the microchip can easily spot and filter out vibrations such as accidental palm pressure or someone placing a coffee cup on the surface.
WHIPPING THE STENCH
It could freshen up the smell of the countryside. A foamy spray has been developed in South Korea to quell the stench from lagoons of pig faeces or heaps of cow dung on farms.
A team led by Kyoungphile Nam at Seoul National University has developed a bacteria-laden foam that neutralises foul-smelling compounds such as ammonia and hydrogen sulphide. The foam is based on a solution of the protein keratin (which makes up hair and nails) combined with a strain of Pseudomonas bacteria that feeds on smelly compounds and converts them to odourless ones.
To ensure as many bugs as possible are exposed, the solution is turned into a foam by passing compressed air through it. 鈥淚t is like whipping cream,鈥� says Nam.
The American Society for Microbiology annual conference in New Orleans last week heard that in tests on a swine waste lagoon, the foam cut ammonia emissions by two-thirds, and hydrogen sulphide by three-quarters.
