Tom Igoe got his hands on a Peppermill circuit board, and took it out for a spin:

Nicolas Villar sent me a sample of the PepperMill, a new sensor board he and Steve Hodges designed at Microsoft Research in Cambridge, UK. It’s a nifty little board. You attach a DC motor and the board can an output voltage when the motor is turned, and analog signals telling you the direction and speed of the motor. It turns a DC motor into a rotary encoder, of sorts.

Wiring is very simple. The motor connects to the two spring connectors at the top of the board. Direction and Speed pins connect to two analog inputs on your microcontroller. Ground connects to your microcontroller’s ground. The motor generates voltage when you spin it.

Check out Tom’s article for circuit diagrams, source code, and information on obtaining a Peppermill board to experiment with. Using PepperMill to turn a motor into a sensor

(Tom is a member of the Arduino team and the author of Making Things Talk).

Making Things Talk
Our Price: $29.99
Programming microcontrollers used to require an expensive development environment costing thousands of dollars and requiring professional electrical engineering expertise. Open-source physical computing platforms with simple i/o boards and development environments have led to new options for hobbyists, hackers, and makers. This book contains a series of projects that teach you what you need to know to get your creations talking to each other, connecting to the web, and forming networks of smart devices.