Project

# Title Team Members TA Documents Sponsor
7 Non-Intrusive Smart Unlocking Mechanism for College Dormitory Rooms
 Arnav Mehta
Raghav Pramod Murthy
Yuhao Cheng
 John Li design_document1.pdf
final_paper3.pdf
grading_sheet1.pdf
other1.pdf
proposal1.pdf
video
# Non-Intrusive Smart Unlocking Mechanism for College Dormitory Rooms

Team Members:
Raghav Pramod Murthy (raghavp4)\
Arnav Mehta (arnavm7)\
Yuhao Cheng (yuhaoc7)

# Problem
Many college students living in dorms frequently face the problem of forgetting their keys. For many students, it’s their first time having to manage keys to get into their rooms, and with busy schedules, it’s very easy to forget or even misplace them. This can create a huge hassle. While some systems, like facial recognition systems, can bypass the standard key-lock system, they are not feasible to install on the college dorm doors; they need to be drilled into the interior of doors, which is costly. Other forms of authentication, such as voice recognition, are not easy to add either. This brings us to a more practical and non-intrusive solution: a lock/unlocking mechanism that does not modify the internal locking system of the door. Almost all door locks can be unlocked through the rotation of some exterior component of the door like the lock or the handle. This naturally leads us to explore a solution geared towards a flexible rotation system that can more easily integrate with existing door locks.

# Solution
We propose a portable system that turns the lock on the door (similar to how a person on the inside of the door would manually turn it to let someone in). This non-intrusive unlocking mechanism will be portable and transferable – it can be easily removed from one door and put onto another. The user attempting to access a room would scan their face on an app, and make a sound for 5 seconds (picked up by a microphone on the cellphone) to initiate voice authentication. The authentication would occur in the backend. If the face and the voice match a face and voice that has been previously registered on the app, the web app will send a signal to the microcontroller to initiate the unlocking process. The user will also be able to register other faces and voices (for example for their roommate) to allow multiple people to use this unlocking system. An important note is that this entire unlocking system will not interfere with manual unlocking with a key.



# Solution Components

## Subsystem 1: Turning Mechanism
This will be the component that physically turns the lock to unlock the door once it receives a signal.

ESP32-S3 microcontroller chip\
DRV8825 Stepper Motor Driver\
Stepper Motor: STEPPERONLINE Nema 17 Stepper Motor Bipolar 2A\
Custom PCB\
LM1117-2.5 Voltage Regulator\
12 V Battery\
Flexible Steel Cable to turn the handle

## Subsystem 2: Facial recognition + Voice Recognition app/User Interface for Authentication

Function: Authenticate the user by scanning their faces and analyzing their voice

Components:
Android app\
Flask backend hosted in GCP\
Google Cloud speech-to-text + recognition API\
DeepFace open source model to compare faces\
MongoDB instance to store face data / voice data


# Criterion For Success

Unit Test Goals:
1. Desired accuracy of the facial recognition model: 95% (on large online dataset and around 20 of our own pairs of cellphone images)
2. Desired accuracy of the speech-to-text + recognition API model: 90%
3. Processing times (from when user submits voice and face to when the signal is sent to the PCB) under 5 seconds

Functionality Goals:
Portability/Transferability of Unlocking System:
1. We will achieve this goal if we can mount our contraption onto a door in under ten minutes.

Facial Recognition + Voice Recognition:
1. We will achieve this goal if users who authenticate themselves (registering their face and voice), take a picture of themselves, and submit a voice sample can unlock the door without a key.
2. We will achieve this goal if an unauthorized user (a user who has not authenticated themselves with face and voice through the app) is unable to open the door.

Four Point Probe

Simon Danthinne, Ming-Yan Hsiao, Dorian Tricaud

Four Point Probe

Featured Project

# Four Point Probe

Team Members:

Simon Danthinne(simoned2)

Ming-Yan Hsiao(myhsiao2)

Dorian Tricaud (tricaud2)

# Problem:

In the manufacturing process of semiconductor wafers, numerous pieces of test equipment are essential to verify that each manufacturing step has been correctly executed. This requirement significantly raises the cost barrier for entering semiconductor manufacturing, making it challenging for students and hobbyists to gain practical experience. To address this issue, we propose developing an all-in-one four-point probe setup. This device will enable users to measure the surface resistivity of a wafer, a critical parameter that can provide insights into various properties of the wafer, such as its doping level. By offering a more accessible and cost-effective solution, we aim to lower the entry barriers and facilitate hands-on learning and experimentation in semiconductor manufacturing.

# Solution:

Our design will use an off-the-shelf four point probe head for the precision manufacturing tolerances which will be used for contact with the wafer. This wafer contact solution will then be connected to a current source precisely controlled by an IC as well as an ADC to measure the voltage. For user interface, we will have an array of buttons for user input as well as an LCD screen to provide measurement readout and parameter setup regarding wafer information. This will allow us to make better approximations for the wafer based on size and doping type.

# Solution Components:

## Subsystem 1: Measurement system

We will utilize a four-point probe head (HPS2523) with 2mm diameter gold tips to measure the sheet resistance of the silicon wafer. A DC voltage regulator (DIO6905CSH3) will be employed to force current through the two outer tips, while a 24-bit ADC (MCP3561RT-E/ST) will measure the voltage across the two inner tips, with expected measurements in the millivolt range and current operation lasting several milliseconds. Additionally, we plan to use an AC voltage regulator (TPS79633QDCQRQ1) to transiently sweep the outer tips to measure capacitances between them, which will help determine the dopants present. To accurately measure the low voltages, we will amplify the signal using an JFET op-amp (OPA140AIDGKR) to ensure it falls within the ADC’s specifications. Using these measurements, we can apply formulas with corrections for real-world factors to calculate the sheet resistance and other parameters of the wafer.

## Subsystem 2: User Input

To enable users to interact effectively with the measurement system, we will implement an array of buttons that offer various functions such as calibration, measurement setup, and measurement polling. This interface will let users configure the measurement system to ensure that the approximations are suitable for the specific properties of the wafer. The button interface will provide users with the ability to initiate calibration routines to ensure accuracy and reliability, and set up measurements by defining parameters like type, range, and size tailored to the wafer’s characteristics. Additionally, users can poll measurements to start, stop, and monitor ongoing measurements, allowing for real-time adjustments and data collection. The interface also allows users to make approximations regarding other wafer properties so the user can quickly find out more information on their wafer. This comprehensive button interface will make the measurement system user-friendly and adaptable, ensuring precise and efficient measurements tailored to the specific needs of each wafer.

## Subsystem 3: Display

To provide output to users, we will utilize a monochrome 2.4 inch 128x64 OLED LCD display driven over SPI from the MCU. This display will not only present data clearly but also serve as an interface for users to interact with the device. The monochrome LCD will be instrumental in displaying measurement results, system status, and other relevant information in a straightforward and easy-to-read format. Additionally, it will facilitate user interaction by providing visual feedback during calibration, measurement setup, and polling processes. This ensures that users can efficiently navigate and operate the device, making the overall experience intuitive and user-friendly.

# Criterion for Success:

A precise constant current can be run through the wafer for various samples

Measurement system can identify voltage (10mV range minimum) across wafer

Measurement data and calculations can be viewed on LCD

Button inputs allow us to navigate and setup measurement parameters

Total part cost per unit must be less than cheapest readily available four point probes (≤ 650 USD)

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