Grading Scheme :: ECE 445 - Senior Design Laboratory

Grading Scheme

 

The grading scheme for the course, as well as links to specific requirements for each assignment/deliverable and evaluation sheets, are given in the table below. Due dates for each assignment/deliverable can be found on the course Calendar. Please note:

Below is the points breakdown for all assignments/deliverables for the course, sorted chronologically:

Item Team / Individual Score Points Evaluation Sheet**
Project Selection Form Individual 5 None
Lab Notebook Individual 50 PDF
Weekly TA Meetings Team N/A None
Weekly Team Update Meeting Team 3/session None
Team Contract Team 5  
Project Proposal Team 25 PDF
PCB Design Exercise Individual 10 PDF
Soldering Exercise Individual 10 PDF
Design Document
Requirements and Verification		 Team 40 PDF
Individual Progress Report Individual 25 PDF
Mock Demo Individual 5 None
Final Demo * Team 150 PDF
Final Presentation * Individual 50 PDF
Final Report: Technical Team 30 PDF
Final Report: English/Format Team 20 PDF
Peer Reviews (2 total) Individual 40 (total) None
Teamwork & Participation Individual 20 None

* Grades for these will be the average of the TA and Instructor grades; peer review grades will be used to provide feedback.
** Evaluation Sheets are subject to minor changes.

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.