Inclinometer based low-cost biofeedback balanceboard for injury rehabilitation

This paper details the design and development of a device that can, through the mechanism of biofeedback, assist individuals undergoing rehabilitation for leg injuries. The device consists of two plates, a base plate which is fixed and a top plate on which the user stands and can be tilted. The two plates are separated by an automotive ball joint and four springs which provide a damping force. A high resolution two axis inclinometer detects the angle of tilt of the platform, and thus implicitly the user´s balance, then sends this information to a personal computer via a microcontroller unit. The tilt information is displayed on the computer monitor to provide immediate, real-time visual feedback to the user. The damping springs, all with a similar spring constant, provide a smooth and linear response over the operating range. Experiments confirm that the inclinometer was highly accurate and responsive. The graphical computer interface conveys feedback about the user´s balance to them as they operate the device. The sensor output is also logged into a database for future retrieval and analysis to monitor the progress of a patient.