The detection of relative motion or orientation between a user and a computing device can be used to control aspects of the device. For example, the computing device can include an imaging element and software for locating positions, shapes, separations, and/or other aspects of a user's facial features relative to the device, such that an orientation of the device relative to the user can be determined. A user then can provide input to the device by performing actions such as tilting the device, moving the user's head, making a facial expression, or otherwise altering an orientation of at least one aspect of the user with respect to the device. Such an approach can be used in addition to, or as an alternative to, conventional input devices such as keypads and touch screens.