Microsoft Research's prototype 'Peppermill' self-powered device. (Credit: Microsoft)

The days of scouring the couch cushions for batteries may be numbered. Researchers from Microsoft's lab in Cambridge, England, have created a media remote control called "Peppermill" that converts the twisting motion required to use it into the energy needed to power it. It's a research prototype, not a product, but it points to the larger possibilities in the area of "human-powered user interaction."

Peppermill is an example of "user interface devices that are able to source their power from the physical effort involved in interacting with them, and thereby operate without the need for batteries," write the Microsoft researchers, Nicolas Villar and Steve Hodges, in the paper they presented last week (PDF) at the international conference on Tangible, Embedded, and Embodied Interaction, or TIE 10.

The project gets its name from the fact that the device looks a bit like a pepper grinder. Users hold it with two hands, using one to turn the knob at the top. The three buttons are used in conjunction with the knob for different inputs. For example, holding down the green button and turning the knob adjusts the volume.

Peppermill includes a small motor, a circuit, a microcontroller and a radio transmitter.

"When the user turns the knob, the microcontroller powers up and samples the inputs from the supply circuit, as well as the state of the three additional buttons," they write. "It encodes and transmits the speed of turn, direction of turn and state of the buttons (pressed/released) as a single wireless packet. As long as enough power is being generated the microcontroller continually samples and transmits packets at 5ms intervals."

The researchers say in the paper that they're looking into ways of applying the concept to other types of devices, citing the example of motion-based video-game control systems such as Nintendo's Wii game controller.