Design Review

Video Lecture

Video, Slides

updated Fa 2020

Description

The design review is a 30-minute meeting intended to make sure that the team has a successful project. Students will present and defend their design while instructors and TAs critique it, identifying any infeasible or unsafe aspects and steering the team toward success. Instructors and TAs will ask questions throughout and may choose the order of blocks to be discussed. Specifically, here is what the course staff are looking for:
  1. Evidence that the overall design and high-level requirements solve the problem stated.
  2. Check if the overall design has suitable difficulty for course standards and completion in one semester. Scope may need to be adjusted if otherwise.
  3. Check team members' engineering preparedness to implement each module.
  4. Check that each team member is assigned an equal portion of the project effort.
Prepare for the following sequence.
  1. Promptly project the design document on projector.
  2. Introduce team members (name, major, and the project part each is in charge of).
  3. Present problem statement and proposed solution (<1 minutes) following the template in DDC (see Description 1.a)
  4. Present design overview (<5 minutes)
    1. High-level requirements: check DDC
    2. Block diagram: check DDC
    3. Physical design
  5. For the remainder of the review, you will participate in a detailed discussion of the design. Plan to cover each block, one at a time, beginning with the most critical. The course staff will ask questions and may step in to guide the discussion. Be prepared to discuss all aspects of your design with a focus on the following.
    1. Requirements & Verification: (see DDC); We'll look at all the important block requirements. Prepare to justify the components chosen and compare with important alternatives.
    2. Evidence that the design meets requirements (use the following as applicable)
      • Simulations
      • Calculations
      • Measurements
      • Schematics
      • Flowcharts
      • Mechanical drawings
      • Tolerance analysis: check DDC
      • Schedule: Suggestions:
        1. Think about what you can do in parallel, what has to be sequential;
        2. Work on hardware before software;
        3. Perform unit testing before system testing;
        4. Unit test each module on a breadboard before starting PCB design);
        5. Leave margin for unexpected delays or accidents. You are mostly responsible for those exceptions, just as if you were the owner of this senior design business;
      • Cost:hourly rate is ~$50 not $10. In addition, apply the 2.5x overhead multiplier ($125/hr is the cost of your senior design business), which includes the cost of salaries of you, your boss, CxOs, sales, janitors, etc.

Grading

The DR Grading Rubric is available to guide your DR preparation. Two sample Design Review documents are available as examples of what we expect: a Good Sample DR, a Moderate Sample DR, and a good example R&V table as it was presented in a final report. Notes are made in red type to point out what is lacking. Note that the grading rubrics and point structure may have evolved since these reports were generated, so use them only as a guide as to what we are generally expecting.

Submission and Deadlines

Your design document should be uploaded to PACE in PDF format by Midnight the Friday before design review. If you uploaded a mock DR document to PACE, please make sure that it has been removed before uploading the final DR..

Tech must-know and FAQ for design

Here is the link of "Tech must-know and FAQ for design" which is accessible after logging into g.illinois.edu.

Over semesters, ECE445 course staff have encountered repeated mistakes from students. The document above is designed to provide students with the essential knowledge needed in order to have a good design. Spending 5 min reading it might save you 15 hours later. Also, there might be some quiz questions in your DDC or Design Review. Please help us improve this document. We value your feedback!

CHARM: CHeap Accessible Resilient Mesh for Remote Locations and Disaster Relief

Martin Michalski, Melissa Pai, Trevor Wong

Featured Project

# CHARM: CHeap Accessible Resilient Mesh for Remote Locations and Disaster Relief

Team Members:

- Martin Michalski (martinm6)

- Trevor Wong (txwong2)

- Melissa Pai (mepai2)

# Problem

There are many situations in which it is difficult to access communicative networks. In disaster areas, internet connectivity is critical for communication and organization of rescue efforts. In remote areas, a single internet connection point often does not cover an area large enough to be of practical use for institutions such as schools and large businesses.

# Solution

To solve these problems, we would like to create a set of meshing, cheap, lightweight, and self-contained wireless access points, deployable via drone. After being placed by drone or administrator, these access points form a WiFi network, usable by rescuers, survivors, and civilians. Our network will have QoS features to prioritize network traffic originating from rescuers. Having nodes/access points deployable by drone ensures we are able to establish timely connectivity in areas where search and rescue operations are still unable to reach.

Over the course of the semester, we will produce a couple of prototypes of these network nodes, with built in power management and environmental sensing. We aim to demonstrate our limited network’s mesh capabilities by setting up a mock network on one of the campus quads, and connecting at various locations.

# Solution Components

## Router and Wireless Access Point

Wireless Access for users and traffic routing will be the responsibility of an Omega2 board, with onboard Mediatek MT7688 CPU. For increased signal strength, the board will connect to a RP-SMA antenna via U.FL connector.

The Omega2 will be running OpenWRT, an Linux-based OS for routing devices. We will develop processes for the Omega2 to support our desired QoS features.

## Battery Management System

This module is responsible for charging the lithium-ion battery and ensuring battery health. Specifically, we will ensure the battery management system has the following features:

- Short circuit and overcurrent protection

- Over- and under-voltage protection

- An ADC to provide battery status data to the microcontroller

- 3.3v voltage regulation for the microcontroller and other sensors

In addition to miscellaneous capacitors and resistors, we intend to use the following components to implement the battery management system:

- The MT2492 step-down converter will be used to step down the output voltage of the battery to 3.3 volts. Between the GPS and extra power the microcontroller might consume with an upgraded Wifi antenna, low-dropout regulators would not provide sufficient power in an efficient manner. Instead, we will implement a 2 amp buck converter to improve efficiency and ensure there are no current bottlenecks.

- We will utilize two button-top protected 18650 3400 mAh lithium ion batteries in series to power each node. Placing two of these batteries in series will ensure their combined voltage never falls below the minimum voltage input of the buck converter, and accounting for the buck converter’s inefficiency these batteries should give us about 21 Wh of capacity. The cells we plan on using include a Ricoh R5478N101CD protection IC that provides over-voltage, under-voltage, and over-current protection. Using a standard battery form factor will make them easy to replace in the future as needed.

- A USB-C port with two pulldown resistors will provide 5 volt charging input with up to 3 amps of current, depending on the charger.

- The MT3608 step-up converter will boost the input voltage from the usb-c port and feed it into the charging controller.

- The MCP73844 Charge Management Controller will be used to charge the batteries. This controller supports CC/CV charging and a configurable current limit for safe and effective battery charging.

- The TI ADS1115 ADC will be used for battery voltage monitoring. This chip is used in the official Omega2 expansion board, so it should be easy to integrate in software. We will use a voltage divider to reduce the battery voltage to a range this chip can measure, and this chip will communicate over an I2C bus.

## Sensor Suite

Each node will have a battery voltage sensor and GPS sensor, providing the system with health information for each node. On top of the Wifi-connectivity, each module would have a series of sensors to detect the status of the physical node and helpful environment variables. This sensor suit will have the following features and components to implement it

- Ultimate GPS Module PA1616D will be used for positioning information. This chip utilizes 3.3V which is supplied through our battery management system.

Battery Voltage Monitor

- The TI ADS1115 ADC (mentioned in the BMS section) is for battery voltage monitoring. It interfaces via I2C to the Omega2.

## System Monitor

A system monitor which provides visibility of the overall system status for deployed network nodes. Information that we will show includes: last known location, battery health, and network statistics (e.g. packets per second) from the physical devices.

We plan on using React to provide an intuitive UI, using google-map-react and other React packages to create an interactive map showing the last known location and status of each node.

The backend will be hosted on a server in the cloud. Nodes will continually update the server with their status via POST requests.

# Criterion For Success

We aim to achieve the following performance metrics:

- 1.5 kg maximum mass

- Cover 7500 m^2 (North Quad) with 4 nodes

- Display the last known location, time connected, and battery voltage for all nodes via our system monitor

- 3 hour battery life

- 5 Mb/s WiFi available to laptops and smartphones in the coverage area

[*Link*](https://courses.engr.illinois.edu/ece445/pace/view-topic.asp?id=71252) *to assciated WebBoard discussion*