I'll be applying for a sabbatical to create a microswitch activated gripper thumb. This would be an ultra-low cost, purposely simple design that uses a servo or dc motor to actuate a cable or directly drive the thumb in the gripper thumb prosthetic design of Skip Meetze. The purpose of this micro grant would be to provide $500 of funding for equipment costs. Based on early prototypes, this should be sufficient to purchase electronics for 8-10 mechanical gripper thumbs. This funding would be used to purchase the necessary electronics and create kits to provide to partners interested in creating, testing and providing feedback on the design. Additional plastic and other hardware costs to build the hands and any shipping costs would be covered by my current research lab budget. The requested funding is largely needed to demonstrate that interest in this project from eNABLE as an entity is high. This will strengthen the competitiveness of the sabbatical proposal for the review committee.

Happy to answer any questions anyone has. More details on the project are incoming.

#Description of Proposed Project:

I propose to invent a new form of low-cost, upper limb, 3D printed, electronically controlled prosthetic device. This device will meet a worldwide need for prosthetics for individuals with transhumeral (above the elbow) limb differences. While commercial myoelectric options exist, they are high cost and complex systems that require knowledgeable experts for maintenance, which is inappropriate for users in the developing world where the need is arguably greatest. I will use my expertise in 3D CAD iterate on a current design (the Gripper Thumb of Skip Meetze and Rochester ReNable) to create a prosthetic hand and, possibly, Ugunugu-evolved elbow system that uses simple, low-cost microswitches to detect physical muscle flexing. These microswitches will interface with a small, Arduino microcontroller to actuate motors to open the fingers of a voluntary opening prosthetic device and, possibly, to rotate a prosthetic elbow. This control system will be adaptable by designing flexible 3D printable attachment options for detecting muscle motion in a variety of locations on a users’ body (wrist flexion/extension, elbow flexion/extension, shoulder motion, bicep flexing, etc.) to control both the hand and elbow. By making this system using a microswitch to detect motion, the design should allow for the use of a variety of muscle motions for actuation, based on a user’s unique needs. To allow the use of such a system by a wide variety of users, a full suite of design instructions (including hardware assembly and software calibration instructions) will also be developed. Furthermore, a particular emphasis will be placed on simplicity to maximize the potential impact of this device.

The goals of the proposal are, therefore:

1) Research biomechanical operation of the human body to determine appropriate sites that permit sufficient physical motion of a muscle to be detectable by a microswitch.
2) Design a system that uses microswitches to detect muscle motions at a variety of locations on a user’s body.
3) Interface this switch system with motors through an Arduino microcontroller to control a voluntary opening prosthetic hand and a prosthetic elbow.
4) Create an easy to follow software calibration system so users can personalize the system to their own unique situations.
5) Create full assembly guides for hardware and software systems to the design can be recreated by eNABLE volunteers throughout the world.

#Expected results/impact:

Electronic prosthetics are highly desirable to provide functional devices for a variety of amputation cases. A simple, low-cost, lightweight eNABLE design could be transformative for a variety of cases not currently well-served by eNABLE designs, including bilateral and above-the-elbow amputees. By keeping the design low-cost and simple, it should be deployable in developing regions where the needs are high but access to technology precludes more complicated myoelectric designs.

#Estimate of work effort involved:

A detailed description of the work involved is provided in the timeline below. Briefly, it will require studying of muscle groups for placement of microswitches to allow efficient actuation of a servo motor, creating arduino simple arduino code to link motor control with button activation and creating simple guides for recreating the design.

#Estimated timeline for completion:

August-September 2019 – Study of muscle groups for identification or microswitch placement. Testing of the electronics (using microswitches to control servos through an Arduino). Coding of microswitch interface with servos through Arduino.
October 2019 – Creation of parametric, 3D-printed enclosures for microswitch sensors. Adaptation of currently available 3D printed prosthetic hand and elbow designs. Integration of microswitches into 3D printed prosthetic elbows and hands.
November 2019 – Testing of microswitch operation of prosthetic hand and elbow. Adjustment of software interface for easier calibration by volunteers.
December 2019 - Creation of hardware build guides. Creation of software installation and calibration guides. Deployment of guides to partners in the wider eNABLE community. Potential deployment to individuals in need of devices in Nicaragua through collaboration with the MU DPT program and their clinical partners.

#Names of individuals responsible for deliverables:
Eric Bubar

#Amount of funding being requested:
$500 - subject to negotiation. Intention of the grant is to demonstrate not insignificant buy-in from the eNABLE community to strengthen the competitiveness of the proposal for a sabbatical committee.

#A brief overview of my background with e-NABLE:
I have been a very active eNABLE member since 2015. I am a member of the SPC and have created and shared a variety of resources with the eNABLE Educational Community for testing functionality of eNABLE devices. I have also provided a variety of proof-of-concept videos of the mechanical gripper thumb, as proposed, on the eNABLE Facebook R&D group (https://www.facebook.com/enablemarymount/videos/683148082060085/)