Development of an Open Source Prosthetic Hand Platform Scott Garrett In the field of upper extremity prosthetic devices, advancements in technology drive the design of products which are becoming capable of restoring the lost functions of the native hand. While several dexterous devices have been developed to serve this purpose, they remain prohibitively expensive and thus are not a viable option for many upper extremity amputees. To address this problem a prosthetic hand platform was developed utilizing the open source Arduino microcontroller and off-the-shelf electrical components. Using these resources, a novel finger actuation mechanism was developed to show how a prosthetic hand platform could be developed which is capable of individual finger actuation, multiple actuation modes, sensing of forces at the individual fingers, providing force feedback to the user, and control of finger actuation through a variety of control inputs. After going through several iterations of hand’s mechanical components, electronics, and firmware a final prototype was built to showcase the possible capabilities of the open source prosthetic hand platform. This prototype consisted of several groups of subcomponents including an auto-flexing / extending finger design, a modular palm/ servo attachment base, and a wrist section which housed the hand’s electronic components, power supplies, force feedback system. The open source prosthetic hand platform was then verified using a series of tests to quantify several performance characteristics of the final prototype. Battery life and grip strength during continuous use were evaluated and demonstrated that the hand could provide consistent grip force during up two hours of initial continuous use. Also, the grip performance of the hand was assessed through the grasping of spherical objects with varying surface textures, diameter, and weight. Furthermore the hand was tested in various “real life” applications including manipulating and sorting small objects, opening doors, grasping moderately heavy objects such as water bottles, and sensitive objects such as an egg. Lastly, the platform was connected to a myoelectric input circuit to demonstrate compatibility with advanced electro-physical inputs. These tests demonstrated that the platform was capable of performing some of the dexterous tasks performed by prohibitively expensive available robotic upper extremity prosthetic devices. Further developments could be made to the open source prosthetic hand platform including enhancements to the platform’s finger force sensing and feedback mechanisms, consolidation of the electronics, refinement of the auto-flexing / extending fingers, and integration with a silicone covering and patients residual limb socket. These future iterations of this platform could help provide a dexterous prosthetic hand platform at lower cost to a wider patient base.