The ability to perform range of motion can help human maintain mobility and flexibility. The transitional device for measuring range of motion is Goniometer, a manual method. This method is depended on users' experience and skill which could lead to wrong interpretation and results. The purpose of this project is to design and develop a prototype for measuring Range of Motion (ROM) by using Inertial Measurement Units (IMUs). The prototype, called ROMie, is including hardware and software. ROMie had been validated for accuracy and sensitivity at 45, 60, 90 and 180 degrees. ROMie was tested for forty times at each angle,. The results showed that ROMie has the overall accuracy greater than 95 percent. Sensitivity is equal 1 at 95 percent confidence interval and greater than 0.875 at 99 percent confidence interval.
