Gadget watch: The Power Purse

You're out shopping and your mobile phone starts ringing, but before you can take that all important call the battery runs out.

Annoyances such as this can become a thing of the past if every woman knew about Solarjo's solar handbag, otherwise known as the Power Purse.

What can it do?

The solar-powered bag charges as you walk, and as long as your gadgets are plugged into the carrier's USB port, they'll charge too.

Joe Hynek, a doctoral student in mechanical engineering at Iowa State University, designed the quirky gadget that uses the sun's natural energy to power your small electronic devices.

Mobile phones, a digital diary, iPods or MP3 players, satellite navigation devices, voice recorders and even small cameras can all be charged by the free renewable energy stored in the Power Purse.

How does it work?

The black, rectangular purse is covered with laminated solar panels which resemble a very thin camera film, separated by white lines.

There's extra padding in the purse for protection and a zipper for security.

The bigger picture A closer look at the solar-powered bag.

Mark Bryden, a mechanical engineering professor at Iowa State, predicts the idea could bloom into other sorts of wearable items.

Already, there are backpacks that convert solar energy into battery power. Another new backpack design generates electricity from the motion of hiking.

Hynek wants to market the Power Purse to environmentally conscious consumers and expects it to retail at 150.

Featuring clear plastic handles, its good looks are complemented by the high-fashion metallics which have been seen on the catwalk runways this season.