Like to head out in the boat for a spot of fishing? All you have to do is first find the fish. The

sonar connects to your smartphone so you can

. It features GPS, a catch logbook, and lets you track weather and lunar cycles. The small device is shock resistant and watertight. Attach it to a line, toss it in the water and check the app for the data it's sending back. The sonar reports via Bluetooth up to 25 metres away on water depth and temperature, the contours of the bottom and at what depth the fish are swimming. The internal 3.6 VDC 600 mAh battery powers around 6 to 9 hours of continuous use on the water surface. Now all they need is guided fishing lines.


ON THE GRID: Electricity is fundamental in our modern society so we need to keep a careful watch on the power grid and infrastructure.
Existing sensors to monitor these things have needed power supplies and signal conditioners. A passive smart sensor from The Hong Kong Polytechnic University can produce large and clear output voltage signals 2,000 times higher than current sensors. The chip is around 1 mm thick and can be placed on any sensing point of interest such as electrical cables, conductors and junctions. It detects magnetic fields generated by electricity and recognises telltale changes of currents within electrical equipment. The smart wireless sensors can be used in otherwise inaccessible locations to notify potential and actual failures. That's smart to get rid of the need for power.

PRINT FUN: 3D printing can be particularly useful for designers and manufacturers, but combining different materials and achieving different colours can be hard work. The Objet500 Connex3 Color Mutli-material 3D Printer combines droplets of three base materials, reducing the need for separate print runs and painting. It incorporates traditional 2D printer colour mixing, using cyan, magenta and yellow to be able to create hundreds of colour combinations in base materials of rubber and plastic. That means end products of widely varying flexibility and rigidity, transparency and opacity. The printer should help industrial designers halve the time it takes to bring prototypes to market. You know you'll always be out of cyan when you need it.

WALL SCREEN: Sony's 4K Ultra Short Throw Projector looks like a piece of furniture but uses laser technology to project a 373 cm image at 4K resolution onto a nearby wall. It includes built-in speakers and cabinets too. A 1.6x power zoom lens means you can size the image to suit the wall and the room. Make the projector look like another piece of furniture: that's a winner.

BLUE SCREEN: If you try to project an image onto a glass window the light will just pass straight through. Project onto a wall though and you should see the image just fine, though of course you can't see through the wall. Researchers at MIT found a way to inexpensively and easily create transparent sheets of plastic which include nanoparticles tuned to scatter only certain colours of light, while letting all the other colours pass through. The sheet of plastic could then be attached to a window and used as a projection surface. This could be useful for a heads-up system on a car windscreen for example, or for information on a shop window. The researchers used silver nanoparticles that produced a blue image, but they say it should be possible to create full-colour displays using the same technique. It's not clear what happens if a blue object is placed behind the transparent plastic.

Miraz Jordan,