Abstract: An angle sensor for an orthopedic rehabilitation device includes a magnet and Hall effect sensor. The magnet is attached to a first member of the orthopedic rehabilitation device, and the Hall effect sensor is attached to a second member of the orthopedic rehabilitation device. The Hall effect sensor detects the presence of a magnetic flux created by the magnet, and produces an output voltage signal that changes as a function of the magnetic flux detected by the Hall effect sensor. As the first member rotates relative to the second member, the magnet rotates relative to the Hall effect sensor, which causes a change in the magnetic flux detected by the Hall effect sensor. The change in magnetic flux causes a change in the magnitude of the output voltage signal generated by the Hall effect sensor, which is converted into an angular equivalent.