Project

# Title Team Members TA Documents Sponsor
39 Enhancing campus dorm security, intruder detecting system.
beixi zhang
Danni Yang
Jaeho Shin
Dongwei Shi design_document0.pdf
final_paper0.pdf
proposal0.pdf
Jaeho Shin | Jshin79
Beixi Zhang | Beixiz2
Danni Yang | dyang46

The first measure of campus dorm security is the entrance where the students are required to swipe their i-card to enter the building. The student is not to allow any strangers to follow them in through the unlocked door, however, these days the rule is loosely enforced and have caused a series of theft to occur on campus.

The idea was vaguely discussed in the previous post, this project proposal aims to answer the unanswered questions with the additional details . https://courses.engr.illinois.edu/ece445/pace/view-topic.asp?id=27045

The idea around this project is that student before entering the door will give the number of people that will enter the door following the swipe of an i-card. Once the input is given it will trigger the people counting mechanism attached on the PCB board (made up of mmWave sensor, DSP, and MCU) to make sure that the count inputted is being respected.

In the case where the count is not respected the algorithm will be set to raise the flag to light up the LED lights to alert the front desk. In addition to it, we will implement the LED counters to give them the needed information to analyze the situation (number given as input and the number of people who have entered the building following the key swipe).

The biggest challenge in this project is making sure that the mmWave sensor accurately detects the people in the small clustered environment as they pass through the campus dorm door. We chose to work with the mmWave sensor because it has ability to distinguish nearby objects from each other and it has high resolution. A mmWave system that resolves distances to wavelength has accuracy in the mm range at 76-81GHz(with a corresponding wavelength of about 4 mm),so it has ability to detect movements that are as small as a fraction of a millimeter. Meaning that mmWave will be able to detect people closely clustered.

We will have to design the PCB board to consist of the DSP and MCU for evaluating the image working with the mmWave sensor.

This is a good project for the senior design because it incorporates both software and hardware designs to implement. We will be using the input from the user on how many people to enter through the door and use the counting mechanism implemented with the mmWave sensor to detect that the count per student swipe is being respected, alert otherwise.

The project itself will be a standalone will not be attached to the actual locking mechanism of campus dorm door nor student's i-card reading system but it will have a mock signal from either the USB keyboard or the keypad attached to the PCB to trigger the above mentioned algorithm and mechanism to show the potential of adding this project on top of currently existing campus dorm security system to enhance the system itself.

Answers to previously unanswered questions:

1. How will it tell apart people coming in or out?
-mmWave sensor is capable of keeping track of object's velocity, angle, and position at the time of detection (depending on software implementation) and keeps track of it. Therefore using the directions, we will be able to tell apart people going in or out. Also sensor should be activated only when given the input to start counting.

2.How will it tell apart people clustered together in the narrow door environment?
-As long as people are couple centimeters apart the sensor will be able to differentiate the objects.

3.Competitions? How is this project unique?
-While there are several different implementation of people counting mechanism that is being used for the everyday business purpose but during our research we were unable to come across a mechanism where they have to respect the number given in the input to make sure that the count is being respected. Our project is focused on enforcing the rule within our campus as well as improving the quality of life in secure environments where all staffs are to ID themselves in.

For references and further detail.
Overview of mmWave sensor: http://www.ti.com/sensors/mmwave/overview.html
Potential Keypad: http://www.ti.com/tool/TIDA-00509

ATTITUDE DETERMINATION AND CONTROL MODULE FOR UIUC NANOSATELLITES

Shamith Achanta, Rick Eason, Srikar Nalamalapu

Featured Project

Team Members:

- Rick Eason (reason2)

- Srikar Nalamalapu (svn3)

- Shamith Achanta (shamith2)

# Problem

The Aerospace Engineering department's Laboratory for Advanced Space Systems at Illinois (LASSI) develops nanosatellites for the University of Illinois. Their next-generation satellite architecture is currently in development, however the core bus does not contain an Attitude Determination and Control (ADCS) system.

In order for an ADCS system to be useful to LASSI, the system must be compliant with their modular spacecraft bus architecture.

# Solution

Design, build, and test an IlliniSat-0 spec compliant ADCS module. This requires being able to:

- Sense and process the Earth's weak magnetic field as it passes through the module.

- Sense and process the spacecraft body's <30 dps rotation rate.

- Execute control algorithms to command magnetorquer coil current drivers.

- Drive current through magnetorquer coils.

As well as being compliant to LASSI specification for:

- Mechanical design.

- Electrical power interfaces.

- Serial data interfaces.

- Material properties.

- Serial communications protocol.

# Solution Components

## Sensing

Using the Rohm BM1422AGMV 3-axis magnetometer we can accurately sense 0.042 microTesla per LSB, which gives very good overhead for sensing Earth's field. Furthermore, this sensor is designed for use in wearable electronics as a compass, so it also contains programable low-pass filters. This will reduce MCU processing load.

Using the Bosch BMI270 3-axis gyroscope we can accurately sense rotation rate at between ~16 and ~260 LSB per dps, which gives very good overhead to sense low-rate rotation of the spacecraft body. This sensor also contains a programable low-pass filter, which will help reduce MCU processing load.

Both sensors will communicate over I2C to the MCU.

## Serial Communications

The LASSI spec for this module requires the inclusion of the following serial communications processes:

- CAN-FD

- RS422

- Differential I2C

The CAN-FD interface is provided from the STM-32 MCU through a SN65HVD234-Q1 transceiver. It supports all CAN speeds and is used on all other devices on the CAN bus, providing increased reliability.

The RS422 interface is provided through GPIO from the STM-32 MCU and uses the TI THVD1451 transceiver. RS422 is a twisted-pair differential serial interface that provides high noise rejection and high data rates.

The Differential I2C is provided by a specialized transceiver from NXP, which allows I2C to be used reliably in high-noise and board-to-board situations. The device is the PCA9615.

I2C between the sensors and the MCU is provided by the GPIO on the MCU and does not require a transceiver.

## MCU

The MCU will be an STM32L552, exact variant and package is TBD due to parts availability. This MCU provides significant processing power, good GPIO, and excellent build and development tools. Firmware will be written in either C or Rust, depending on some initial testing.

We have access to debugging and flashing tools that are compatible with this MCU.

## Magnetics Coils and Constant Current Drivers

We are going to wind our own copper wire around coil mandrels to produce magnetorquers that are useful geometries for the device. A 3d printed mandrel will be designed and produced for each of the three coils. We do not believe this to be a significant risk of project failure because the geometries involved are extremely simple and the coil does not need to be extremely precise. Mounting of the coils to the board will be handled by 3d printed clips that we will design. The coils will be soldered into the board through plated through-holes.

Driving the inductors will be the MAX8560 500mA buck converter. This converter allows the MCU to toggle the activity of the individual coils separately through GPIO pins, as well as good soft-start characteristics for the large current draw of the coils.

## Board Design

This project requires significant work in the board layout phase. A 4-layer PCB is anticipated and due to LASSI compliance requirements the board outline, mounting hole placement, part keep-out zones, and a large stack-through connector (Samtec ERM/F-8) are already defined.

Unless constrained by part availability or required for other reasons, all parts will be SMD and will be selected for minimum footprint area.

# Criterion For Success

Success for our project will be broken into several parts:

- Electronics

- Firmware

- Compatibility

Compatibility success is the easiest to test. The device must be compatible with LASSI specifications for IlliniSat-0 modules. This is verifiable through mechanical measurement, board design review, and integration with other test articles.

Firmware success will be determined by meeting the following criteria:

- The capability to initialize, configure, and read accurate data from the IMU sensors. This is a test of I2C interfacing and will be tested using external test equipment in the LASSI lab. (We have approval to use and access to this equipment)

- The capability to control the output states of the magnetorquer coils. This is a test of GPIO interfacing in firmware.

- The capability to move through different control modes, including: IDLE, FAULT, DETUMBLE, SLEW, and TEST. This will be validated through debugger interfacing, as there is no visual indication system on this device to reduce power waste.

- The capability to self-test and to identify faults. This will be validated through debugger interfacing, as there is no visual indication system on this device to reduce power waste.

- The capability to communicate to other modules on the bus over CAN or RS422 using LASSI-compatible serial protocols. This will be validated through the use of external test equipment designed for IlliniSat-0 module testing.

**Note:** the development of the actual detumble and pointing algorithms that will be used in orbital flight fall outside the reasonable scope of electrical engineering as a field. We are explicitly designing this system such that an aerospace engineering team can develop control algorithms and drop them into our firmware stack for use.

Electronics success will be determined through the successful operation of the other criteria, if the board layout is faulty or a part was poorly selected, the system will not work as intended and will fail other tests. Electronics success will also be validated by measuring the current consumption of the device when operating. The device is required not to exceed 2 amps of total current draw from its dedicated power rail at 3.3 volts. This can be verified by observing the benchtop power supply used to run the device in the lab.