Tech Universe: Thursday 04 July

By Miraz Jordan

An inventor has made a door that will open to the sound of his dog's bark. Photo / Thinkstock
An inventor has made a door that will open to the sound of his dog's bark. Photo / Thinkstock

HARK HARK A BARK: Looking for a project for your Raspberry Pi computer? One Irish inventor wanted his dog to be able to let itself out and in through the door, so he rigged up a bark detector. The dog barks at the door, the Raspberry Pi recognises the bark, releases a latch and allows a counterweight to swing the door open. That's a nice bit of fun, but it doesn't seem to close the door again.

UNDER ONE ROOF: 1.7 million square metres is pretty big for a building. In fact, China's New Century Global Center could fit in 20 Sydney Opera Houses. That's what makes it the world's largest free standing building. The New Century is 500 metres long, 400 metres wide and 100 metres high and houses business offices, movie theatres, shopping malls, a theme park and even a fake Mediterranean village. That's 170 hectares or 420 acres. You could probably live there and never see the outside world at all.

TURN THE WIND: There's wind energy and tidal current energy, so how about combining the two? The world's first hybrid wind-current power generation system will be installed off the coast of Japan later this year. The wind turbine will be 47 metres above sea level. The tidal turbine will have a diameter of 15 metres. The two sections will be connected by a power generator that should produce enough electricity for 300 households. Testing begins soon. It seems logical to combine the two forms of energy generation.

AN EYE ON THE SUN: NASA's IRIS spacecraft is on a mission to understand the area between the photosphere and corona of the sun. Most of the sun's ultraviolet emissions come from the region IRIS is studying , and those emissions affect Earth's climate. IRIS will use spectrometry and imaging to explore the area, sending back data that can be used to create a 3D model. Its rocket placed IRIS into a sun-synchronous polar orbit that will allow it to make almost continuous solar observations during its two-year mission. Presumably that's one eye that can look directly at the sun.

GOODBYE SALT: Chemists in Germany and the US have found a new way to take the salt out of seawater. Their technique is simple and takes less energy than conventional desalination. The discovery could make a lifesaving difference to the millions of people who live near the coast but have little clean drinking water. The trick is to apply a small voltage to the junction of a microchannel with two branches on a plastic chip filled with seawater. The voltage neutralises some of the chloride ions in the seawater, changing the electric field so it redirect salts into one branch and desalinated water into the other. At the moment their desalination device is tiny and inefficient, but the chemists are confident it can be scaled up to create a commercial device. Add a solar panel for the power supply and millions of people could benefit.

Miraz Jordan, knowit.co.nz

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