A novel infinitely variable transmission (IVT) is presented that has the potential to be an order of magnitude smaller than existing technologies leading to several potential applications in robotics (Fig. 1). Unlike more common continuously variable transmissions (CVTs), this transmission can reverse the direction of the output relative to the input without clutches or extra stages, affording new opportunities for energy savings or power bursts. This potentially enables its use across a broad range of mechanical energy conversion applications including robotics, transportation, and heavy industry, where it could dramatically increase total system efficiency. Its controllable impedance also makes it well suited to human-safe robotics and haptic feedback systems.