Milestone 2

Milestone 2.1 - Project Plan

Team Roles

Software Development: Nicholas DiMeglio (Lead), Shady Kamel (Support)

Mechanical Development: Rohit Jayas

Electronic Development: Shady Kamel

Advisors

Professor George McConnell, Professor Mahmoud Al-Quzwini

Project Management

TinnX is using a structured shared Google Drive to keep track of tasks, a Gantt chart for responsibilities and deadlines, and meticulously organized folders and files. The shared drive will also house SOLIDWORKS files and revisions, audio files and samples, and any mathematics formulas needed. It currently also holds website resources, as well as the team's budget and expenses. For code storage and version control, TinnX will use GitHub. For communication, the team has a text message group chat and communicates frequently regarding project updates and ideas. Lastly, TinnX meets three times a week in person to conduct meetings and work on the project.

Software

For our minimum viable product (MVP), we will be using C/C++ to create a program that generates customizable tinnitus relief audio signals. We will also be using libraries to achieve the audio implementation we are after. Finding the best library will take some experimentation, which is mentioned in our test plan as we wait for project materials to arrive. This program will likely run on a PC and stream audio to our bone conduction headphones using Bluetooth.

Hardware & Electronics

Our MVP will use off-the-shelf bone conduction headphones to transmit the tinnitus relieving audio signals generated by our software. We will be using off-the-shelf over-ear headphones for our demonstration at the Innovation Expo. After completing our MVP, we hope to design and build our own custom bone conduction headphones for better functionality and battery life. This will require designing the housing in SOLIDWORKS, a printed circuit board (PCB) designed using Autodesk Fusion 360, two transducers, and other electronic components to ensure proper functionality.

Task Breakdown

Fall Semester

1. Milestone 1 (September 5 - October 11)

   • Understand who our customers are, evaluate their needs, and lay out their requirements

   • Map customer needs to requirements

   • Onboard project advisors and begin discussion on how to best approach this problem

2. Milestone 2 (October 12 - November 29)

   • Create a project plan with a task breakdown to provide an overview of the project and how the team has structured the work to be done

   • Come up with different design concepts to assess possible design alternatives

   • Select the most viable design concept

   • Create a system diagram and process flowchart for the entire tinnitus relief system

   • Understand hardware and software requirements

   • Develop a reasonable test plan balancing time, objectives, deadlines, and our budget

3. Team Assessments (November 30 - December 6)

   • Assess team performance and reiterate team responsibilities

4. Presentation (December 13)

   • Develop a professional presentation incorporating principles learned in Design VI, Design VII, IDE 400, IDE 401, and MGT 103

Minimum Viable Product

1. Create an application that generates tinnitus canceling sounds

2. Build prompts or a prompting system that guides the customer to find their frequency and customize it to reduce their tinnitus as much as possible

3. (Potentially part of the MVP) Design an external control board for medical personnel to calibrate and manipulate what the customer hears

Spring Semester

1. Develop an optimized pair of bone conduction headphones that focuses on battery life

2. Enhance the prompting system

3. Establish a well-thought-out system for ENTs to set up, monitor, and adjust patient usage of the device

Innovation Expo (April 26, 2024)

Milestone 2.2 - Concepts

TinnX developed five potential concepts for a tinnitus relief system. For a complete list of requirements, please refer to Milestone #1. Primarily, the customer shall be able to easily and safely use the device for extended periods of time, in all environments, to provide relief from tinnitus.

Concept 1

Concept 1 helps solve tinnitus by sending externally generated frequencies to the ear. By doing so, this will 

• Figure out the tinnitus frequency that a person hears

• Send frequencies to the eardrum to help reduce the tinnitus sound the person is hearing

• Fine tune the frequency that person receives from the earbuds to neutralize the tinnitus sounds

• Have the person use comfortable earbuds and easily recharge them for 24/7 use

Concept 2

Concept 2 follows the same premise of concept 1, but instead will be done with bone conduction headphones. The process that takes place is as follows:

• Find the tinnitus frequency that a person hears

• Send frequencies to the cochlea as an internal source of sound to help reduce the Tinnitus sound the person is hearing 

• Fine tune the frequency that person receives from the earbuds to neutralize the Tinnitus sounds

• Have the person use comfortable earbuds and easily recharge them for 24/7 use

Concept 3

Concept 3 combats tinnitus by targeting damaged hair cells in the inner ear, a common cause of tinnitus. This method involves:

• Researching and creating a suitable inner ear hair replacement / prosthetic (promising research)

• Finding and removing all damaged inner ear hairs without posing a risk to healthy hairs

• Replacing the damaged ear hairs with the artificial hairs

• These replacement ear hairs shall respond to sound waves and transmit electrical signals to the brain just as natural ear hair cells do

Concept 4

Concept 4 is similar to Concept 3 as it also targets damaged inner ear hair cells. This approach would narrow down the target market to customers who suffer from tinnitus and also have very sensitive hearing:

• Find and remove all damaged inner ear hairs without posing a risk to healthy hairs

• Do not replace with prosthetic hairs

Milestone 2.3 - Concept Selection

TinnX first analyzed the proposed concepts on a surface level. One of the biggest limitations facing the project is that, since the team does not have a biomedical engineer, testing on humans is prohibited. After observing project limitations, as well as the project constraints including little time in the academic year and a small initial budget ($400), concepts 3 and 4 were eliminated. TinnX is determined to provide a product that puts the customer first and provides an accessible, safe solution to minimizing tinnitus. As a result, it is outside of the project scope, team abilities, and allowed difficulty to guarantee this promise when pursuing concepts like 3 and 4. TinnX targets an affordable solution, and a surgery of that caliber may prove unaffordable to many. This does not align with the mission statement.

This leaves us with concepts 1 and 2. The reason why the group decided to proceed with concept 2 instead of concept 1 is the untapped potential with the idea of bone conduction headphones. Tinnitus is an internal sound that a person hears, and as a result, would be very difficult for a device such as earbuds to help send frequencies to an eardrum to neutralize the tinnitus sound. Bone conducting headphones are a special product as they have the ability to transmit sound to a person without the need to go through the eardrums. The way that bone conduction headphones work is that they are able to sit on a person's cheekbones and vibrate the sound directly to the cochlea, bypassing the need of getting the signal through the eardrum. By doing so, a person will be able to hear the frequency from the bone conduction headphones as an internal sound and this will be able to help reduce the tinnitus frequency that a person hears. 

Furthermore, an in ear solution is dangerous. Tinnitus relief is required indefinitely, and having the customer's ears blocked all the time is not safe. The customer will not hear the environment around them, which is especially dangerous when walking in an area with cars present. Keeping the customer's ears open is the logical solution. Bone conduction is the only technology readily available to our team that will keep their ears open while still providing tinnitus relief.

Milestone 2.4 - Design

The following image is the system diagram for the TinnX minimum viable product. This is a very simplified system to enable proof of concept testing.

The following image is the process flowchart for the MVP.

Milestone 2.5 - Analysis

Hardware Specifications

For the hardware aspect of the design, this involves a myriad of components. The purpose of the hardware components that are involved is that it will house all of the electronics components, such as the wiring, transducers, and custom PCB's. By housing all of the electrical components, this will help in making sure all of the components are secured in place and will work accordingly. Additionally, there will be an emphasis on making an outer case that is durable and can last for long-term daily use. TinnX intends to have their customers use the device 24/7, and as a result, have worked on making sure that the casing is durable for long-term use. PETG will be used to 3D print the housing. Additionally, the product should work in all kinds of environments. Therefore, silicon weatherproofing will be applied to the inside of the housing to protect the electronics. A rubber cover will be used to protect the charging and data uploading port.

Software Specifications

The software required for the TinnX device will be built in C/C++, using external audio libraries. The best audio library will be selected after experimenting with the Shokz bone conduction headphones (refer to Test Plan). This software will have to interface with external physical controls, and obtain values to be used throughout the program. TinnX will not collect personal identifiable information (PII), so cloud services and APIs will not be used. It will run locally as it will eventually be contained within the bone conduction headphones. The prototype software will run on a laptop and stream to the Shokz headphones via Bluetooth.

Electronics Specifications

Firstly, an Arduino Pro Micro ATmega32U4 will be used as the microcontroller board for the external physical controls used by the ENT or audiologist. This board was chosen as the ATmega32U4 will make the controls recognizable as a human interface device (HID), providing flexibility when combining all of the elements of the tinnitus relief system. Most of the controls will be potentiometers with knobs to fine tune signal parameters. A durable housing will also be made for the controls. Next, a pair of Shokz bone conduction headphones is used for the prototype. Eventually, custom bone conduction headphones will be developed to optimize for battery life and specific functionality for the customer. When building this pair, two 8 ohm 1 Watt bone conductor transducers (with wires) from Adafruit will be used. A custom PCB will be designed in Autodesk Fusion 360 and will be sent to be manufactured. 

Budget Allocation Analysis

So far, TinnX has ordered Shokz bone conduction headphones. This purchase totaled $108, leaving $292.

• Bone conduction transducers (x2) - $30 (including fees and shipping)

• Over-ear headphones - $60 (including tax)

• Custom PCB ~ $40 (estimate including shipping)

• ATmega32U4 ~ $20 (estimate including shipping)

• Potentiometers & other electronic components ~ $35 - 40

After these future purchases, the remaining budget should be around $100.

Milestone 2.6 - Test Plan

There are many variables to account for when testing and ensuring real tinnitus relief. The following items are not all of the possible tests available to TinnX, as more testing opportunities may be presented in the future. Currently, the plan is to:

• Identify the frequency response of bone conduction transducers in a near ideal environment with minimal noise. Ideally, the transducers will be able to accurately produce 20Hz - 20KHz to be able to generate canceling signals for all tinnitus cases.

• Identify the frequency response of bone conduction transducers in a noisy environment and determine what their weaknesses are. What frequency ranges does it struggle with?

• Conduct tests on the casing, such as structural analysis and durability tests, to determine how durable the device is to make sure that it can withstand long-term use by the customer

• Find out how hot the electronics can get, and with that information, conduct thermal analysis on the casing to see if it can withstand the temperatures and for how long it can do so

• Test the bone conduction transducers with a variety of different materials to test if the material affects transmission of audio. This may help or harm the frequency response and producible signals. Materials may range from different kinds of plastic available in the Stevens 3D printing lab, to other materials such as wood or metals. Foam materials may also be tested to provide more comfort to customers who will wear the device all day. All results will be recorded and analyzed to determine the best materials to work with

• Test possible audio libraries to find the most suitable candidate. The "best" library will provide a balance between audio quality and resource usage.

• Generate software tests to account for as many errors as possible. Predict possible customer or ENT misuse to add safety measures / error catches

• Waterproof the electronics and test how much they withstand the elements expected in a customer's day-to-day life

• Conduct battery life tests to gauge how often a customer will need to charge their device

• Measure the wear and tear of electronics after constant use to figure out how durable the electronics are within the casing before needing repairs or replacement

• Attempt to perform radiation tests (depending on available testing devices) to ensure the electronics are not in violation of radiation laws worldwide

• Reach out to potential industry partners to test product perception

• Test if the external control board is dimensioned large enough to be usable by any medical professional, but small enough to be easily integrated into existing offices and environments. Would this need a protective case?

© TinnX™, Nicholas DiMeglio, Rohit Jayas, Shady Kamel 2023