Thieves in the London Borough of Brent may turn green at a new police initiative — literally.

devices detect intruders and spray thieves with a fine mist of a special substance. The mist contains a mix of chemicals that are almost impossible to wash out of clothes, and can stay on the skin for weeks. Under UV light the chemicals show up as a bright green. Advertising that the devices are in use is intended to deter thieves, while the colour can help catch out those suspected of the crime. Smart thieves will doubtless turn to disposable coveralls and masks.

LEVERAGE: The Mipwr iPhone case doesn't just contain a battery to help keep the phone charged, but a small pop-out lever so you can charge the phone in an emergency. Move a switch and the lever pops out of the side of the case. Pump the lever for a few minutes by squeezing your hand to get a couple of minutes of talk time. Build your arm muscles while staying connected in an emergency.


ON THE CARDS: Would you like instant credit card sized prints from your photos? That's what the instax mini 90 Neo Classic camera from Fujifilm can do. The camera includes various shooting modes, including double exposure and a bulb mode for light trails or night views, as well as macro and party. The camera takes film packs to produce prints that are 62 mm x 46 mm. That could be a novel way to create a business card on the spot when networking.

THROUGH A GLASS CLEARLY: If you have a DSLR its lens almost certainly contains numerous heavy and expensive optical elements, many of which compensate for the deficiencies and errors in the others. How about if you could do away with all that specially ground glass and replace it with a cheaper and lighter simple lens and some very clever software? Researchers have devised software that can apply complex algorithms to the output of a poorly performing lens such as a single plano-convex lens. The software eliminates colour fringing to deblur the image and produce a sharper picture. The notion of replacing much of a physical lens with an app is very intriguing.

P12 IN THE SKY: The P12 Martin Jetpack is on its way — at least for rescue workers, police and fire services. The Kiwi-designed jetpack has a maximum airspeed of 74 Kph and can fly for up to 30 minutes up to a height of 900 metres. The engine itself weighs 60 Kg and must be overhauled every 200 hours. Maybe for now you'd better stick to the skateboard for getting to work.

Miraz Jordan,