Human body motion tracking is a key technique in robotics, virtual reality and other human–computer interaction fields, for interactive mixed reality applications. Human motion tracking for rehabilitation is widely discussed by researchers in the last period, being motivated by the increased number of patients with motor function disability. For such patients rehabilitation is an important step to restore their functional capability to normal or close to normal. To reach this target, a patients’ activities need to be continuously monitored, and subsequently corrected. This involves accurate identification, tracking, and post-processing of movement. This paper thus proposes an open loop real time angle computation algorithm designed in Matlab®. Its efficacy was tested using an Arduino Nano® coupled with the MPU-6050 as the Inertial Measurement Units (IMU). The advantages of the proposed algorithm are presented by comparison with the already existing and widely used methods.