Course Overview :: ECE 445 - Senior Design Laboratory

Course Overview

Welcome to ECE 445 / ME 470 Senior Design ZJUI Spring 2024!

Welcome to the class! If you've looked at the course Calendar, you've probably already noticed that this class is quite different from most other classes in the department. The class only meets as a whole for the first four weeks of the semester. During these lectures, you will meet the Course Staff, learn about specific requirements, resources, and project choices for the course, and have a chance to meet other students. These are some of the most important weeks for the class since the decisions you make during this time will determine what you'll get out of this class and, in many ways, how much you'll enjoy it.

In this course, you will form teams and propose projects that solve an engineering problem in a unique way. The projects generally involve a device that you will design, build, and demonstrate. We are excited to see what projects you create this semester! In the midst of an ever-changing learning environment, we want to encourage you to think, create, design, and build exemplary projects. We want to ensure that your experience in 445 demonstrates your potential as an engineer graduating from the University of Illinois.

This course is taught hybrid for ME and ECE students, and some projects are mentored by ZJUI faculty. Here are a few items that you will need to consider as we enter this semester.

Expectations and Requirements

We have high expectations for students participating in ECE/ME Senior Design. You are soon to be an alumnus of one of the top engineering schools in the world. Our alumni hold themselves to high technical and professional standards of conduct. In general, projects are expected to be safe, ethical, and have a level of design complexity commensurate with the rigour of the ECE/ME Illinois curriculum. Requirements for specific assignments due throughout the semester can be found by looking through the Grading Scheme for the course. Please read through this documentation well before each assignment is due. Specific due dates can be found on the course Calendar.

Below are a few words of wisdom to keep in mind throughout the semester to increase your enjoyment and success in the course:


Miniaturized Breath Sensors

Rui Cai, Yiyang Chen, Qiaozhi Huang, Yingzhuo Wang

Featured Project

## Group Member:

- Yiyang Chen[yiyangc5];

- Rui Cai[ruic2] ;

- Yinzhuo Wang[yw28];

- Qiaozhi Huang[qiaozhi2]

## Problem

Flow monitoring is crucial in many applications. We want to build a miniaturized breath sensor system that can monitor asthma.

## Solution Overview

In this wearable respiratory monitoring device, a new fluid measurement device, similar in principle to a traditional hotline, will be used to collect real-time data on a person's breathing rate. In contrast to the traditional hotline, materials such as graphene and carbon nanotubes are used as probes which is much more robust and have lower TCR(temperature coefficient of resistance). This material--graphene fiber (GF) will be welded into Wheatstone bridge and the voltage output of GF will demonstrate the velocity of air flow by controlling the temperature of the GF. Then, we will use filter to eliminate noise of the signal and do Fourier Transform to demonstrate the frequency of respiration. After that, this signal can be sent to smartphone. With previous training data online, we can analyze the signal of respiration and conclude the probability of asthma. We plan to use a mobile app to show users breathing data, summarize the data and make recommendations. We will use Bluetooth for data transmission.

## Solution Components

### Flow Sensor System

The resistance of a specific material changes at different temperatures, and the flow sensor system's control circuit measures the change in resistance to achieve constant temperature control of the sensor probe. In the thermostatically controlled fluid sensor subsystem, the heat carried by the fluid at different speeds through the sensor probe is the same as the heat provided by the compensation circuit, so that the fluid flow rate can be accurately measured. Graphene and carbon nanotubes are widely used in these sensor probes, and sensor probes using pencil and paper have recently been proposed as a new type of sensor probe. The processing of sensor probes is challenging and there are advantages and disadvantages to various methods, including soldering and metal clamping, and we are trying to design a small, low-cost and robust sensor probe.

### Circuit

The circuit of our design consists of three sections: Wheatstone Bridge, Amplifier, and Feedback control. We need to adjust the resistance of the Wheatstone Bridge to construct and balance a working space for GF sensor. As it states in previous, the flow would change the GF material’s resistance, thus create a voltage difference on both sides of the Wheatstone Bride. This difference will be amplified by the operational amplifier, and the voltage regulator will change the excitation voltage on the Wheatstone Bridge in order to keep the temperature of GF stable. The difficulty of our design come from the feedback control design. One possible way is to use transistors. In addition, if we want to eliminate the environmental temperature effect, specific temperature compensation measure should be implemented, such as add a temperature sensor in another Wheatstone Bridge. The circuit should keep the GF temperature stable and output the voltage change, this output signal will transfer to next section and be processed and analysed.

### Signal Processing and Analysis

First, we must use filter to eliminate noise of signal. As we all know, the high frequency noise can have a negative influence on the signal, which does harm to our analysis of asthma. Therefore, we must do FFT on signal we get from circuit and use high frequency filter to eliminate certain noise. Second, to calculate the probability of asthma, we must collect training data of respiration online. These data can be used to do machine learning. With those training data, the signal can be analysed easily.

### Result

Visualization Bluetooth Low Energy (BLE) features Low power consumption and faster transmission speeds. Therefore, we choose BLE to transmit data to mobile phone on this wearable respiratory monitoring device that requires long battery life and only a small amount of data transfer. We're also going to keep the interface simple and add analysis function to the app.

## Criterion of success

- Wearable and Miniaturized In the current study, wearability and miniaturization directly determine the industrialization potential of this new type of sensor. The portability of the product will help to achieve 24/7 patient health monitoring. Therefore, the development of wearable and miniaturized health monitors is considered as one of the criteria to measure the success of the product.

- Comfortable and Flexible Flexible sensors that conform to human science will significantly improve the comfort of wearing the product and determine the user's willingness to wear it. Flexibility and comfort are one of the goals of the product.

- Environment Friendly Environmental protection is becoming an increasingly important issue to be addressed today. The development of environment-friendly sensors is the goal of this research. Conventional biosensors will inevitably use environmentally hazardous materials such as plastic. this study will use degradable materials, such as paper, instead of plastic for product development.

- Low Cost Low-cost respiratory health monitors facilitate product penetration and daily use.

- Reliable and Stable As a medical product, the reliability of the product determines the safety of the life of the target object. A highly reliable and high-performance respiratory monitoring device can effectively guarantee the occurrence of accidents.

## Distribution of Work

Yiyang Chen (ME), Rui Cai (EE) and Qiaozhi Huang (ME) will be responsible for the construction of the fluid sensors, the design of the wearable device, the design and debugging of the circuitry, which are closely linked and we agree that there is no need for an overly clear distribution of work, Rui Cai will lead the development and fabrication of the circuitry. Yingzhuo Wang (ME) will be responsible for the development of the wireless Bluetooth data transmission technology, the visualization of the monitoring results and the implementation of the interactive functions.