This article presents the design and implementation of a bioelectronic knee integrated into a transfemoral mechanical prosthesis manufactured in 3D printing. This device is made to improve the human gait cycle in the lifting, rocking, and support phases. For its implementation, control subsystems were integrated for the spatial variables and the conditioning of native muscle signals generated by the contractions of the vastus and biceps of the stump of a patient with trans-femoral amputation. The readings of the position and angular velocity signals were made through an interface adapted to the non-amputated limb as a response pattern. The scope of this article is defined by the reading, monitoring, control, and improvement of knee movements in a bioelectronic prosthesis in the phases of the human gait cycle. Finally, the importance of reducing the cost of the device is highlighted through the optimization of resources, construction materials, and electronic elements, with a low cost value.