Dahon, maker of folding bikes, has shown off a rather ingenious and incredibly useful little gizmo at the Eurobike show. The BioLogic FreeCharge is a little silicone-encased box which hooks up to your bike’s generator hub and siphons off power for charging your gadgets. The unit comprises a battery and circuitry to both store electricity and to smooth the inevitable bumps and spikes in the generator’s output.

Then you simply plug in your cellphone or iPod to the USB port, juicing the GPS as you ride. The time to a full charge is three hours, but the most likely use for this is topping-off, keeping your gadgets going indefinitely as you trundle along. And think about cycle touring: you can charge iPods, phones and even camera batteries, freeing you from the tyranny of camp-sites and power outlets. Fantastic, and $100 when it ships in March 2010.

Charge your iPod with your bike [Bike Hugger]