What is it? The dynamo has been around for decades, powering your bike light as you pedal. Now someone has taken that idea and applied it to smartphones, creating a device that charges up your iPhone as you exercise. When’s it due? Get charging now. Why are we excited? It’s such a simple idea you wonder why we haven’t seen more products like it before. You can strap it to your arm and go for a run, or clip it to your leg as you cycle. What better incentive to put down the Apple TV remote and get some exercise?