We present FreeDigiter, an interface for mobile devices which enables rapid entry of digits using finger gestures. FreeDigiter is an infrared proximity sensor with a dual axis accelerometer and requires little signal processing. Initial laboratory experiments attain accuracy rates of 99.0%; and the system is tolerant to highly varying lighting conditions. The FreeDigiter system requires little power and could be implemented in a very small form factor appropriate for controlling in-ear hearing aids, small MP3 players, and hands-free mobile phone headsets.