Lab

Recommended Tools

In addition to the resources that the course provides, students may find it useful to obtain the tools below:

  • wire cutter
  • wire stripper
  • needle nose pliers
  • screwdrivers
  • hex set (ball ends)
  • electrical tape
  • small scissors
  • a small file

Lab Resources

The Senior Design Lab is located at ZJUI room D225. This lab provides you access to various equipment, some spare parts, computers, and a space to work on your senior design project. In addition, course staff will make themselves available in this lab during their office hours to provide guidance on your project throughout the semester. Your weekly meetings with your TA will also likely be at this location.

It is our intention that this laboratory space provides you and your team with all the tools you would need to develop and test your project (within reason, of course!). If there is something that you require in the lab to complete your project that does not exist in the lab, talk to your TA and we will see how we can solve your issue.

Lab Rules

There are two overarching rules of working in the Senior Design Lab (and, frankly, any shared lab). First, be safe, and second, be courteous. Lab privileges will be revoked if you fail to complete the required laboratory safety training or if you break any of the lab rules. Specific points and examples of what we expect:

Breaking the rules or exhibiting bad laboratory etiquette will lead to a loss of points and/or revocation of laboratory access.

Lab Bench Reservations

We do not expect the lab to become so crowded such that finding a lab bench to work at becomes difficult. However, in the case that this does happen (particularly in semesters with very high enrollment), we will move to a Lab Bench Reservation system. Reserving a bench guarantees that spot for you, however each team may only book one lab bench at a time, and for a maximum of 4 hours per day.

If the lab needs to move to a reservation-based system, you will be notified ahead of time.

A few ground rules:

  1. You may use a lab bench (a) during a time for which you have it reserved or (b) any time during which it is not reserved in the system (on a first-come-first-served basis). However, if you are working at a bench that is unreserved and somebody reserves it using the online system, the group with the reservation gets the lab bench.
  2. There is a limit on the amount of time for which you can reserve benches in ZJUI D225. The limit is currently a total of 4 hours of total bench time in the lab per group per day (e.g., 2 hours at Bench A and 2 hours at Bench B would max out your team's reservations for the day). While this may seem restrictive, keep in mind that the course serves more than 30 groups in a typical semester and the lab has only 14 benches. Also keep in mind that you can work at a bench if it is unreserved.
  3. Some lab benches have specialized equipment at them, such as digital logic analyzers. Try to reserve the lab bench that has the equipment that you need.
  4. Cancel reservations that you will not need as soon as possible to give other groups a chance to reserve the lab bench. You can cancel a reservation up to 1 hour before time and not have it count against your daily allotment.
  5. Conflicts and/or reports of people not following these rules should be sent to your TA with the course faculty in copy.
  6. Above all, be courteous. Especially near the end of the semester, the lab will be more crowded and many teams are stressed. Clean up the lab bench when you are done with it. Start and end your sessions on time. Be patient and friendly to your peers and try to resolve conflicts professionally. If we notice empty lab benches that have been reserved, we will cancel your reservations and limit your ability to reserve lab benches in the future. Similarly, do not reserve more time than you will need. If we notice that you are frequently canceling reservations, we will limit your ability to reserve lab benches in the future. Finally, do not try to exploit the system and reserve a bench for 30 minutes every hour for eight hours. We will notice this and revoke your ability to reserve a bench.

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.