Take a shower under an

head and you'll easily know when you've been in there too long: the shower head itself turns red.

in the shower head gradually change colour from blue to green through orange and finally, after about 7 minutes, to red. The change in colour alerts bathers to how long they've been in the shower, which leads to savings in both water and power. That's clever. >


KNEE NEEDS: In the US a titanium prosthetic knee joint alone can cost $10,000. But there are many amputees around the world who need an effective joint that costs less than $100. The JaipurKnee is one solution. The joint is made from an oil-filled nylon polymer that self lubricates with use and weighs less than a kilo. It's composed of 5 plastic pieces and 4 standard fasteners, with a 165 degree range that makes it possible to kneel and squat. And the ultimate outcome: the possibility to live an independent and productive life.

GLASS AND MIRRORS: Have your smartphone see around corners with the Smartphone Spy Lens. Attach the provided metal ring around your smartphone's built-in lens then snap on the Spy Lens which attaches magnetically. The glass lens uses mirrors to take photos at right angles to the phone and can swivel around to easily cover any direction. That's handy for those who like to take photos of their meals.

KEEP THE PHONE CLOSE: It's not what it sounds like: the Micro Phone Lens converts your cellphone camera into a microscope. The tiny soft platinum catalysed silicone lens sticks itself to your cellphone over the camera lens. Peel it off again and store it in its carry case for future uses. It has a 15x base magnification but can accommodate a built-in zoom in the phone. The biggest problem is likely to be its tiny size: it's only around 6 mm in diameter. Get that old contact lens case out.

WATCH YOUR BACK: Fos is a fabric patch that contains a very bright LED grid and can be controlled by a mobile phone. For example, it can display the next turn on the route you're taking. Wear the patch on your back so drivers can see you and your next turn on your bike. The patch includes a software development kit so you can design your own uses. Images can be displayed at up to 60 frames per second. The 30 gram patch is lined with Velcro, includes a 32-bit microprocessor, flash memory and efficient power supply, and offers 64K shades of light for every pixel. Just keep the messages clean.

Miraz Jordan,