Blog Post 5

Final Product:

Note** Video and pictures were taken before some
final changes were made but for the most part reflect what
the final product looked and functioned like

  

Hardware updates:
Since the last post I have printed two more fingers and added them to the hand. I decided to stick with the make-shift solution to replace the hinges for this prototype as I discussed in previous posts. They ended up working well as they had some flexibility to them so that the fingers could contract different amounts around the curvature of an object. I constructed a housing to hold the hand and the servos in place so that the servos could turn and apply a torque to the strings connected to each finger. All the servos were connected separately to the breadboard and wired up to power and digital pins for signaling. Each servo had to be calibrated to a starting position and then I tested to find the value of the desired contraction for each finger. Finally I printed a new ring to house the button/ control system for the prosthetic hand (shown in one of the videos above).

Software updates:
I implement a timer using millis() in order count the number of button presses during a given time interval. I also set up different cases for the hand which I called modes. I then implemented statements that would toggle the mode if the number of button clicks within the time interval was greater than or equal to the threshold value for switching. All of these vales were not hard coded as to make changes such as adding additional functions and changing the time interval possible. The two functions I coded for the demo were a clench function which simply contracted all of the fingers, and the second function displayed an "okay sign". These were simple as they were just meant to showcase the toggle ability of the hand. Overall, I was very happy with how the toggle function was working. It was pretty seamless and worked really all the time with minimal error It was easy to use and felt natural. I did have some issues integrating the servos on to the hand. The interrupts from the millis() timer seemed to interfere with the signaling to the servos. I solved this problem by adding some delays in the loops and powering the servos off of an external power supply.

Future iterations:
I do developing further versions of this prototype both on the physical quality of the prosthetic and the control side. Eventually, I would want to be able to produce a variety of custom prosthetic devices all with customizable control systems that could be selected by the user. I do plan on communicating with potential consumers in the target market to better determine what they would need in a functional prosthetic like this one. For the more immediate next steps, I would like to continue working on the control software to allow more seamless control to the device. I would want to develop more functions for the user to be able to select and more control options. I would eventually like to develop an interface through which users with or without programming experience could implement their own functions based on their specific needs and even customize the control. Another improvement would be making the controller wireless and housing the electronics inside the prosthetic itself. I hope to make all of the code and files open source and possible provide custom kits to those who would like all of the parts packaged together for them. Overall, I am very happy with the progress I have made and I think this prototype does act as a proof of concept for the idea and of course their is room for improvement. I learned a lot through pursuing this project and am excited to see where it takes me through further iterations and how I will be able to apply this knowledge to future projects.