A 3D-Printed EEG based Prosthetic Arm

Nowadays, with the use of 3D printers, the upper limb prosthesis is more available, mainly the myoelectric controlled devices; however, there are some cases where the myoelectric signal is difficult to detect due to the patient's injury. In this case, the Electroencephalography (EEG) controlled prosthesis is more suitable. In this work, we reported a case of a man of 64 years old who received a 13.2 kV. electric shock in his right hand, registering a low electromyographic signal. The prosthetic arm was designed using Blender software, sized and adjusted using the left hand as a reference. All the prosthetic components were 3D printed: hinges with flexible material and the rest with polylactide (PLA). We used three actuators placed on the forearm, which connected through nylon thread to the fingers: one motor for the thumb and the other two motors connected to two fingers for each one. We used the Neurosky Mindwave 2 equipped with a frontal sensor and wireless data transmission and a control unit to obtain the EEG data. The data acquired from the EEG device was filtered and adjusted to the patient's capabilities to find a thresholding value that will be used as a control parameter. As a result, the 3D printed prosthesis was fitted to the patient's stump. The patient was able to perform opening and closing movements of the hand with a force of 11.0 N, able to grab objects used in daily life. We can demonstrate the feasibility of simple control of prostheses by recording EEG data, especially for those whose electromyography signals are challenging to read.