Jessica S.

Hi, my name is Jessica and I am a rising senior at the Bronx High School of Science. I am a veteran of the Construction department of the SciBorgs Robotics Team and I am a part of the Varsity Badminton Team. My starter project is the MintySynth Kit 2.0 and my main project is the knee activity monitor with bluetooth. The MintySynth is an Arduino-compatible synthesizer that fits in a mint box. It uses a microcontroller that is preloaded with the MintySynth software which uses oscillating signals and waveforms to produce sound. I chose the MintySynth as my starter project because I love music. It was also an opportunity to learn a lot about electronics, and circuits; areas of engineering that I didn’t come into contact with before this program. The knee activity monitor is a knee sleeve that monitors the user’s biomechanics while they are performing a certain exercise. It measures the angle and angular velocity of the knee during exercise. Particularly, it tells users whether or not they are doing their rehabilitation exercises properly without a physical therapist present. I chose this project because of my interests in biomedical engineering. This project encompasses many aspects of engineering, like coding and electrical engineering, which are all fundamentally important as a biomedical engineer. 

Engineer

Jessica

Area of Interest

Biomedical Engineering

School

The Bronx High School of Science

Grade

Incoming Senior

Final Milestone

My main project is a knee activity monitor. It is a sleeve that measures the angle that a knee is bending at. This is designed to help people monitor their biomechanics and allow patients to efficiently do certain rehab exercises, like squats, at home without the supervision of a physical therapist. It allows an average person to monitor their biomechanics.

On the knee sleeve, the angle can be measured in two ways. There is a bend sensor that I made using neoprene and conductive fabric. It was created by using neoprene which is the exterior, and velostat, which is in between two pieces of neoprene. Velostat is a conductive fabric that allows resistance to build up. The neoprene and velostat were sewn together using conductive thread. At the ends of the neoprene, there is conductive fabric, where the jumper wires were sewn into. The sensor reacts to decreases in resistance which is caused by bending the sensor. There is also an accelerometer which has a gyroscope in it. The data from the accelerometer can be displayed graphically through Processing. On the wrist sleeve, there is only one method of measuring the angle. I only used an accelerometer, which is a small chip and is more accurate for measuring the bend angle.

From the second milestone, I’ve made several modifications. I originally used an arduino pro mini with a 9V to 5V voltage regulator and then a voltage divider to convert 5V to 3.3V. Instead, I am now using an arduino nano. Although it is slightly larger than the pro mini, it has a 3.3V pin and is able to convert 9V to 5V so I can eliminate the voltage regulating circuit completely. Also, I was going to add a wifi module to my project in order to communicate wirelessly. However, at Ramaz, the wifi network has a captive portal. This requires you to sign in after connecting to the open network which prevents the wifi module from connecting to it. Thus, in order to make the sleeve wireless, I decided to go with a bluetooth module which connects to my laptop and can display the graph in Processing.

My greatest challenge for this project was the wireless communication. I initially wanted to add a wifi module to the sleeves so that the sleeve could send data to a website and the graphical display could be seen by anyone with the website. I had to learn about how wifi works and how I would theoretically send data from the arduino to a server and then to a website. I worked on the several different codes to try to connect the wifi module to the wifi and being able to communicate and configure it from my laptop. However, the captive portal in the Ramaz Wifi preventing me from being able to test out the code and ultimately using that module.

My next step is to be able to display the graph of the data from the accelerometer on either a website or an app. It doesn’t require users to have Processing installed and would ultimately make this sleeve more accessible and easier to use for an average patient.

Documentation:

Project BOM:

Google Drive

Knee Sleeve BOM.xlsx

Arduino Bend Sensor Code:

Github

Bend Sensor Arduino.txt

Bend Sensor Processing.txt

Accelerometer MPU6050 Code:

Github

MPU6050.txt

I2C.txt

Graph.txt

Knee Sleeve Circuit Fritzing Diagram

Wrist Sleeve Circuit Fritzing

Reflection

These six weeks flew by so quickly! I came into this program with a bit of trepidation. I loved the idea of making my own “medical device” and being able to explore so many different kinds of engineering this summer. However, I knew that as soon as I touched upon the coding aspect of the project, I would have to work very hard to not only understand the coding language but also how to create my own code to fit my needs. Six weeks later, I have a working wireless knee and wrist sleeve and I’ve learned that as long as I put my mind to it, as long as I work hard towards a goal, anything is possible.

From this program, one of the most important things I learned was self-learning and problem solving. I came into the program with no experience in coding and electrical engineering. The only engineering experience I did have was being on the construction department of the robotics team. During these 6 weeks, I’ve had to code, create and plan circuits and learn about wireless communication. These are all topics that I probably wouldn’t have even touched upon without the motivation of completing my main project. As I was putting together all of the code, I experienced a lot of challenges. Often, the instructors didn’t know exactly what was causing all of the errors. I had to look up each and every function to understand the syntax and what it did and why it was causing an error. I would revisit my code multiple times a day just to figure out what was wrong. Sometimes it would take days before I figured out what was wrong and how to fix it. But at the end of the day, this program gave me a lot of motivation to explore different fields of engineering with lots of hands on experience. I learned that biomedical engineering is the best field for me because I enjoyed all aspects of my project, from the electrical engineering circuitry side to the computer programming side, and brainstorming how this device could be the next innovation in the medical industry.

Second Milestone

My second milestone was to sew the circuit onto the knee sleeve and to work on my modifications. I sewed the bend sensor onto the sleeve by using back stitches. Once the bend sensor was sewn in, I sewed the arduino board onto the sleeve. I used double sided tape to secure the pcb board and accelerometer onto the arduino board. My first modification was to create a wrist sleeve that performs a similar task. It measures the angle that the wrist is bending at. This would be perfect for people who are doing wrist curls as part of their rehab exercises. This sleeve would tell users when they are performing the exercises correctly. However, instead of using an arduino uno, due to space limitations, I chose to go with the arduino pro mini. Since the input voltage would be 9V from a battery, I needed a voltage regulator to convert it to 5 volts to power the arduino. I created a voltage divider in order to convert the 5 volts to 3.3 volts in order to power a wifi module (esp8266). My next step is to work on the wifi module and be able to communicate with it from my laptop.

First Milestone

My first milestone was to create the bend sensor and compile the code that extracts the data from the sensor. The bend sensor was created by using neoprene which is the exterior, and velostat, which is in between two pieces of neoprene. Velostat is a conductive fabric that allows resistance to build up. The neoprene and velostat were sewn together using conductive thread. At the ends of the neoprene, there is conductive fabric, where the jumper wires were sewn into. The sensor reacts to decreases in resistance which is caused by bending the sensor. I had difficulty with compiling the code that extracts data from the bend sensor. I found code online for both the Arduino and Processing, the graphing program for Arduino, that would print and graph the data. The arduino code for printing the resistance and degree in the serial monitor worked well. However, it seemed that there was a large variation in the output data and I couldn’t figure out why. I continued with the code for Processing anyways but I had a hard time with the code. When I ran the code, I would get a “NaN” error or in other words, a Not a Number error. I scoured forums and example code and I realized that I didn’t write “float inByte = 1” at the beginning of the code which prevented any data from printing or graphing. Once I typed that in, the graph was produced and it was working perfectly. My next step is to attach the accelerometer and work on its code.

Starter Project

For my starter project, I build the MintySynth. It is an electronic musical instrument that fits in a mint box. It uses a microcontroller which is preloaded with the MintySynth software. The software is a wavetable sequencer that uses waveforms to produce sound. The synth is powered by two AAA batteries and generates electric signals by using waves. The ceramic resonator creates an oscillating signal of a specific frequency, which produces the waves that determine the voice or timbre of an instrument and are programmed into the buttons. The wheels, which are potentiometers, vary the resistance in the circuit. Each wheel has a different function, like changing the tempo, pitch of a voice, and duration of each note. The photocell detects changing light levels and changes the pitch of the voice accordingly. It is a light-dependent resistor. When the light level changes by closing the lid, the resistance changes, causing a varying voltage, which changes the pitch of the voice. The 6 pin FTDI header allows you to program the microcontroller by using an adapter. The 3 pin MIDI header sends MIDI signals to other devices. The electrolytic capacitor removes the DC component of the audio output and acts as a high-pass filter, which only allows signals with frequencies higher than the cut-off to pass. The ceramic capacitors are used to allow a FTDI adapter to reset the microcontroller, as a bypass capacitor that smoothes the input voltage, and as a low-pass filter. The MintySynth can also be programmed by yourself to modify the software, add games, etc. Essentially, you can modify it as you would an Arduino.

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