Prosthetic Force Sensor Project

In this project, I modified a previous college student's class project which involved the use of a Servo motor and a potentiometer to control a 3D-printed prosthetic finger. Inspired by his work and my own interest in mechanoreception, I wanted to work on a project which would allow me to develop a prosthetic which mimics the function of receptors in a human finger. The goal of the project is for the finger to increase its grip level based on the pressure sensed by a force sensitive resistor (FSR). The STLs for this project were designed by e-NABLE for use in their existing Phoenix hand design and modified by former college student Paul Kim.

This project uses the variable resistance generated through interaction with a FSR to move the position of the finger. This component can be changed to any electronic sensor that will provide the best accuracy and sensitivity. Future steps for continuation of this project involves the testing of other sensors as well as optimization of the fit of the mold in which the finger lies and potentially a complex system involving multiple fingers could be employed.

Assembly

1) Obtain the following parts

1. Elastic Fishing Line

2. Orthodontic Rubber Bands

3. FSR

4. thumb_knuckle_pin.stl

5. finger_phalanx.stl

6. thumbtip_pin.stl

7. fingertip_short_v2.stl

8. 6 Finger_v2.stl (palm_left_new_supports.stl)

9. SG90 Servo

Links for STL files: e-NABLE phoenix hand, Paul Kim design

2) Assemble the Finger

• Gather parts 5, 6, and 7
• Align the rectangular holes in part 5 and 7 then insert part 6 through the hole
• Take parts 5, 6, 7 and align the remaining hole with the hold in part 8 then insert part 4 through the hole.
• Attach dental bands to the joints of the finger then attach the Servo motor to the slot in part 8 (see Paul Kim's 6 Finger Augmentation Device for more details)

3) Hardware Build

4) Operation

- See Video for details on proper user interaction with this project