Systems and methods for generating an input to a computing device based, at least in part, on movement data generated by one or more ultrasonic transducers are described herein. An example system may include at least one ultrasonic transducer configured to be mounted to a body surface that is proximate to at least one subsurface tendon, and a controller operably coupled to the at least one ultrasonic transducer. When mounted to a body surface, the at least one ultrasonic transducer is configured to detect movement of the at least one subsurface tendon. The controller is configured to operate the at least one ultrasonic transducer to generate movement data based on detected movement of the at least one subsurface tendon, and generate an input to a computing device based, at least in part, on the generated movement data.
