About The Class

"Electronics and Electrical Engineering has become pervasive in our lives as a powerful technology with applications in a wide range of fields including healthcare, environmental monitoring, robotics, or entertainment. Electronics has become a powerful and ubiquitous technology supporting solutions to a wide range of applications in fields ranging from science, engineering, healthcare, environmental monitoring, transportation, to entertainment." (taken from class syllabus)

This project was for my Electronics for the Internet of Things (IoT) course. As the name suggests, we were tasked with an IoT project that had to meet specific criteria.

First, we have to think about these 3 questions:

What is the need for this project?
Do examples of things like it exist?
What is the theoretical/conceptual problem it solves?

After thinking about our project, we also had to make sure that it fit within specific criteria involving sensing, actuation and data transmission:

What are the sensors the project uses?
What is the actuation that the project uses?
What is the data transmission the project uses?

Project

Eventually, my group of 3 engineers (including myself) decided on creating a prosthetic feedback brace which used wireless communication.

Before I dive into the details, let me show the project in full function!

Here are two videos that I had recorded for my non-engineering friend! I wanted to get the project idea and functionality across to them and I figured it would be good to include here:

We felt that the project would meet the needs of a proper sensory feedback system when it came to simple tasks such as knowing when you're holding a cup (and how much strength to use for said cup). This brace allows the user to know when you're in contact with something such as a cup. Once contact is made, a disk vibrator is activated to let the user know that contact was made (not just from a visual standpoint but also from a sensory standpoint). Not only did we want for it to be a working system but in general, we want it to be a dependable system.

There are some modern examples that resemble this project, such as EMG signal cuffs (devices that can record and stimulate electrical muscle signals and peripheral nerves) and ergonomic prosthetic mounts, but the thing is that modern day prosthetics do not have a direct feedback system for the user.

Here are the sensors and actuations that are integrated and embedded into our project:

The biggest problem with our project involved the transceiver modules that we used into our circuitry. We had issues with communication and dual control due to the insufficient capacitors that we soldered onto the transceiver modules, so we upgraded the capacitors from 10 μF to 100 μF. This helped filter the electronic noise that prevented our modules from communicating with each other! Such a basic (yet overlooked) problem, but we managed to figure it out after lots of testing.

I was in charge of helping with the wiring diagram, as well as creating and implementing the Arduino IDE code that we used to control our electronic parts, which is shown below.

Sender Module Code

This code is meant for the ESP32 that serves as the "interactive" part of our prosthetic brace. With the use of a joystick, we are able to control a servo motor that moves our 3D-printed finger. We also can provide input through an FSR sensor that is attached to the fingertip, simulating our prosthetic fingertip coming in contact with something. This code also sends the servo angle and FSR sensor values to another ESP32, which serves as our "receiver" module.

Receiver Module Code

This code is meant for the ESP32 that receives messages and signals from our sender module in order to show the feedback aspect we aimed to display. It receives both the servo angle and FSR sensor values, where it outputs them in two ways: synced servo motor actuation (so the receiver servo motor moves at the same time as the joystick-controlled servo motor) and disk vibrator actuation (by touching the FSR sensor, it activates the disk vibrator). The disk vibrator is the main feedback output that we wanted to demonstrate, since it would let the user know when they are in contact with an item (ex: when they're holding a cup).

This was a straightforward project, but as straightforward as it may be, it took a lot of debugging and circuitry testing in order for us to show proof of concept, which was a wonderful way of integrating both mechanical and electronic systems together as one!

Prosthetic Feedback Brace