Design Review

Video Lecture

Video, Slides

Description

The design review is a 30-minute meeting intended to ensure that the team has a successful project. Students will present (using slides in tandem with their design document) and defend their design while instructors critique it, ask questions, and indentify any infeasible or unsafe aspects. Note that the instructors are not here to attack your design, but to straightforwardly inform you when you may be heading down an unsuccessful path.

Instructors and TAs will ask questions throughout and may choose the order of the blocks to be discussed. Specifically, here is what the course staff are primarily 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 your slides or other content 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 review presentation should be ready before your Design Review. You do not need to upload this powerpoint to the course website. You will be graded on your live presentation on the day of the Design Review with the course staff.

Wireless Charging Table Supporting Multiple Devices with Arbitrary Placement

Kaiwen Cao, Tianyi Han, Tingkai Liu, Zikai Liu

Featured Project

# Wireless Charging Table Supporting Multiple Devices with Arbitrary Placement

# Problem

While more and more device manufacturers adopt wireless charging into their smartphones and headphones, most currently available wireless charging pads only support a single device and require strict alignment between the device and the coil. Misalignment can negatively influence both user experience and charging efficiency. In certain scenarios such as cafeterias, a table that can simultaneously charge multiple devices with arbitrary placement can be useful and COOL, allowing the users to sit wherever they like and to arbitrarily place their devices.

# Solution Overview

We intend to design and manufacture a table with multiple mobile coils placed in an intermediate layer below. Driven by step motors, a tool grabber attaches the coils using electromagnets and drop them in the right place. Computer vision will be used to recognize devices (phones, AirPods, etc.) and guide the chargers to corresponding locations. Once the coil is in place, it will first communicate with the device (Qi protocol) to verify whether the device can be charged wirelessly. If yes, the charging process will start. Otherwise, the coil will be moved back to its original location. The scheduling algorithm ensures the wires get separated and neat.

# Solution Components

* Mechanical subsystem. The main moving component of the system is a large-scale X-Y moving mechanism under the table. The coils will be placed between two panels above the moving mechanism and will be caught and dropped to the right place by the moving tool head. The tool head will be developed with electromagnets or magnets with Z-axis moving capability.

![sketch](https://courses.grainger.illinois.edu/ece445zjui/pace/getfile/18618)

* Vision detection subsystem. This includes a camera and a processing unit. It detects the locations of phones and other chargeable devices and send their positions to the control unit. In real-world settings, pre-installed surveillance cameras may be used as the video source so that no additional camera is required. Embedded GPU (NVIDIA Jetson Nano as a candidate) or cloud service can be used for image processing.

* Power supply control. It is used to control wireless chargers and supply power to devices if and only if the handshake between charger and device is successful. Status will be reported to the central control unit.

* Central control unit and embedded software. According to the output given by the vision detection system or the feedback from the power supply system, the central control unit should move the chargers with proper scheduling algorithm to pair chargers with devices and keep wires of coil separated and neat.

# Criterion for Success

* The vision detection system can localize chargeable device at an accuracy of over 80% and response within 2s.

* The power system can supply powers when a chargeable device is present, and not supply power when the misdetection happens. Correct feedback can be sent to the central control system.

* The mechanical system moves correctly according to the commands given by the central control system.

* The central control system can send correct commands to the mechanical system given the position information from the vision system and the feedback from the power supply system. It should be able to keep wires of charging coil separated.

# Evaluations on Alternative Solutions

The technology of wireless charging emerged some time ago, but its inclusion in commercial devices doesn’t take off until recent years. Intuitively, wireless charging doesn’t bring much additional convenience compared to the wired charging, but its adoption by major manufacturers has proven its value. Similarly, in certain settings such as the cafeteria, charging without alignment may significantly increase user experience, comparing to having only a few fixed charging locations.

An alternative solution to enable table-scale wireless charging is to deploy multiple coils covering the whole table. But it doesn’t solve the alignment problem unless the coils are heavily overlapped, which has been proven to be difficult by already canceled Apple AirPower.