ModeLabs of France has unveiled three new eco-friendly cellphone concepts. All the concepts rely on the inherent movement of their users to automatically regenerate power and signal the possibility of using smaller batteries or even eliminating them entirely. The most advanced model is the “YoYo”, ModeLabs says. Designed to be worn around your neck, the prototype uses the “bounces and swings” generated by your movement and also gets power from built-in solar cells. The company has also revealed the “U-Turn”, a business phone that draws energy from the opening and closing of the keyboard. Their “Runaway” model is worn on your wrist and takes advantage of the faster movement of exercise as its power source. ModeLabs hasn’t said whether or not its concepts will reach production but hopes to market its custom designs to cellphone makers soon.