Mechatronic instruments can create complex sounds that computers and digital instruments have yet to offer. As a specific example, we explore mechatronic chordophones, which use strings as a sound generator and offer a wide array of parametric affordances. The purpose of this work is to review recent approaches for chordophone design and construction, and present current, state-of-the-art devices. We explore multiple mechatronic frames and their components, and we analyze the challenges of building and interacting with these machines. Finally, we review software and hardware approaches that have been implemented to enhance these instruments and to bridge technical and creative restrictions.