It’s a wind up

You’re on the train, you must make that all-important pointless phone-call to someone or other, and then tragedy strikes. Your battery has run down, and your travelling companions are spared another turgid conversation about shopping for aubergines.

Well, now the Zucchini chit-chat can continue, courtesy of the wind-up phone.Developed by alternative energy expert Freeplay, and initially only available for Motorola phones, FreeCharge is a portable device that can be charged with wind-up technology and then connected to your phone.

Freeplay’s first product was a ‘clockwork’ radio based on Trevor Baylis’ now famous idea. This radio was powered by a tensator, a spring that supplies a constant force and drives a small dynamo through a gear chain.

Over the years, Freeplay has improved the technology, introducing first a capacitor to store excess electrical energy, and later a rechargeable battery. With the Freecharge, says Technical Director John Hutchinson, the company has turned the technology into something very different from Baylis’ original concept.

Freeplay has dispensed with the spring, and created what Hutchinson refers to as ‘a direct charge device.’ The battery is charged in real time directly from the winding action. The crank-handle drives a dynamo through a transmission system, and the resulting electrical energy goes straight into a rechargeable battery.

Unlike a spring-based system, the amount of power generated depends upon how quickly you turn the alternator. Hutchinson refers to this as an ‘effort reward’ relationship’.

One of the biggest difficulties Freeplay faced was designing the transmission. In contrast to a spring-based system, where the transmission is downstream from the spring and effectively disconnected from the user, the transmission in the Freecharge must be rugged enough to withstand the strongest of inputs.

It was a challenge, says Hutchinson ‘to get a small, efficient well matched high tolerance gear train that’s extraordinarily strong. The generator we ended up with can absorb 2 to 3 times as much power as the average user can put in.’

The device can be used in a number of different ways. A charged unit can be plugged in to your handset and used immediately, or it can be left to upload its power onto the phone’s battery. If both your phone and the Freecharge unit are completely flat you can plug the Freecharge into the phone and begin cranking. This will charge both the phone and the Freecharge because it generates power at a more rapid rate than the phone can absorb. 30 seconds cranking will generate enough power for a 3 – 4 minutes call.

So why not wind-up PDAs, or even computers?

The applications for this technology are apparently endless. Indeed the company has already integrated similar devices into both foetal heart monitors and navigation systems for yachts. But Hutchinson returns to the notion of ‘a marketable effort – reward relationship.’ While it’s worth cranking like mad to save someone’s life, it simply isn’t worth expending the same effort to get a power-hungry laptop to run for a few minutes.

Despite this, Hutchinson believes that the trend towards power efficient devices, driven by a wireless web, means that it’s only a matter of time before wind-up computers become feasible. In 1998, Apple designed a computer with no mechanical drives called the eMate. Freeplay teamed up with Apple and was able to get 20 minutes out of the eMate after only 30 seconds of cranking. Hutchinson believes that this machine will be ideal for the 3rd world.

The freecharge can also be scaled up to generate more power. The company has developed a foot-powered unit and experimented with integrating solar panels. With a suggested retail price of $65, the FreeCharge is expected to be available in March 2002.