Term Meeting #3 - Sept 31

A project log for Myoelectric Arm Prosthesis

A low cost arm prosthesis that fulfills the need for inexpensive, functional prosthesis

Joyce ZhangJoyce Zhang 10/01/2017 at 21:330 Comments

- We split the team into 4 subteams for the next week to get components ready for 3D printing:


Timeline: Aim to complete by Sunday/Monday (It will be difficult for team 4 (and perhaps team 3) to start before team 1 completes their work) 

Members: Ankit, Kira, Laura (Edit: Liza will also join this team) 


- Fill in the space in the top and bottom palm (excluding the holes for the knuckle joints and screws) 

- Remove wrist and extrude existing forearm into the palm (i.e. create a fixed wrist) 

- Remove everything in the forearm: this includes removing the tube for wires, servo mounts, holes for screws, 9v battery slot, and Arduino Uno frame. We essentially just want a skeletal frame of a forearm with just the thin wall of the forearm remaining.


Timeline: Aim to complete by Tuesday/Wednesday 

Members: Will and Joyce 


- Fix finger joints  

- Adjust knuckle axle position 

- Increase diameter of certain tunnels for the fishing line


Timeline: Aim to complete by Tuesday/Wednesday 

Members: Jenna, Isha (Edit: Karam will also join this team) 

Tasks: - Rotate thumb to a fixed position (use your own discretion as to what angle appears to be suitable) 

- Created fixed axle connected to the palm of the hand for the thumb to spin on. To do this you could extrude the existing axle into the palm or create your own design. I have posted a few links below if you want to look at other designs[1]. (please note: when designing the axle that the palm is split into 2 pieces, a top and bottom, as such keep in mind that the axle may be cut in 2 when printing the 2 pieces of the palm) 

- Increase the size of black forearm cover to make access to the forearm easier. Additionally, create an overlap between the 2 white and one black piece of the forearm and add screw holes so we can easy open up the forearm instead of glueing it together.


Timeline: Aim to complete by Wednesday/Thursday (It will be difficult to start before team 1 completes their work, perhaps start designing the servo mounts first and add them in when team 1 is finished) 

Members: Timmy, Evan, Maya, James 


- Extra screw hole in palm near pinky finger 

- Create mounts for 3 (perhaps 4) sg90 servos in the forearm. 

Some things to keep in mind: the servos need a clearance of about 0.3mm between each face of the servo and the wall of the mount, also ensure there are small cylinders cut out for the screws (about 1.8mm diameter and 5mm deep). In the fusion file there is a body I imported called “5 servo mount” if you recall from the Thursday meeting this is the mount that I used in the red prosthetic arm. Feel free to adapt this and use it, cutting it down to either 3 or 4 servo mounts instead of 5.

- Adds tunnels for the fishing line to guide them through the palm to their respective fingers