The wind-up radio, invented by the UK's Trevor Baylis, has become an icon of benign technology. Beloved of environmentalists and design gurus alike, it has already shifted over 3m units worldwide. Now the company that bought the idea from Baylis has moved into the mobile phone market. This month, Freeplay will launch a wind-up mobile phone charger to go with the recently commissioned wind-up torch for the Swiss Army knife.
The bright yellow Freecharge looks like a sporty Walkman or maybe even a latter-day football rattle. But what it does is allow you to power your mobile by using a sustainable form of energy. To power your mobile phone with the Freecharge you simply windup and a mere minute of elbow grease will give an average of five minutes talk-time and up to four hours' standby, depending on the state of the phone's battery.
But who would want to use one? Well, me for one. I recently took a Freecharge to Oxfordshire, where I spent the weekend on a barge on the Thames.
After a day or so my battery ran out. I'd only made a couple of calls home and sent the odd text messages. We had only one plug socket on the barge, so the device came in very handy.
It is heavy and a little too clunky to slip into your pocket. I'd feel a bit daft using it in the centre of town. For a moment, it did feel as if I was winding an old field telephone, but that added to the fun. More importantly, we could ring the barge's owner when the engine looked like it was overheating. Without it, we'd have had to stop and go hunting for a payphone.
Later, when down to the last drop of juice - with the phone's alarm bleating in my ear - I was able to sustain a call just by winding. If I had have been making an urgent call, say to a passport office or a credit card company - it could have been a lifeline. And with the summer festivals coming up, I'd say the Freecharge is essential.
Freeplay says that it is not just a camping company. They are also marketing the phone to heavy users and business people. There are plans to expand the use of the Freecharge to include PDAs by next year and the company plans a similar charger for laptops.
"At any one time we have a lot of experimentation underway," says Rory Stear, CEO of Freeplay. "The hardest thing for us was designing a product that wasn't crazily out of kilter with the size of a mobile phone."
The Freecharge is manufactured by Motorola using Freeplay technology. But adapter modules will be available for other major manufacturers at no extra cost, says Steer.
And there is an ethical reason for using the Freecharge. According to environmental groups, the production of mobile phones is harmful to wildlife and politically problematic. This is because most batteries use a rare mineral called coltan that might be an excellent conductor, but some observers believe that coltan mining is funding civil wars in Congo and Zaire.
"We think the Freecharge is a great idea," says a spokesperson for Friends of the Earth. "Because it reduces energy consumption and the emissions that are affecting climate change. It is also a very practical energy solution that helps people get used to the idea of sustainable energy."
Floating through the locks in Oxfordshire's exquisitely manicured countryside, I couldn't help but agree.
· The Motorola Freecharge will be available from major electrical retailer, priced £59.
