Design Document

Description

The design document communicates the complete and detailed design of your project. It is substantially more detailed than the proposal and prepares you for the assembly phase of the semester. A quality design document is the key to a successful project (sample document). Use the following format:

  1. Introduction

    • Problem and Solution:

      One to two paragraphs explaining the context of the problem to be solved by your project, including any relevant references to justify the existence and/or importance of the problem (i.e., the need or want for a solution). Justify the novelty of your solution or explain the expected improvements of your solution over previous results.

    • Visual Aid

      A pictorial representation of your project that puts your solution in context. Not necessarily restricted to your design. Include other external systems relevant to your project (e.g. if your solution connects to a phone via Bluetooth, draw a dotted line between your device and the phone). Note that this is not a block diagram and should explain how the solution is used, not a breakdown of inner components.

    • High-level requirements list:

      A list of three to four objective characteristics that this project must exhibit in order to solve the problem. These should be selected such that if any of these requirements were not met, the project would fail to solve the problem. Avoid vague requirements that can be interpreted a number of ways (e.g. "The radio subsystem should work reliably."). Each high-level requirement must be stated in complete sentences and displayed as a bulleted list.

  2. Design

    • Block Diagram:

      A general block diagram of the design of your solution. Each block should be as modular as possible and represent a subsystem of your design. In other words, they can be implemented independently and re-assembled later. The block diagram should be accompanied by a brief (1 paragraph) description of the critical subsystems and what they do.

    • Physical Design (if applicable):

      A physical diagram of the project indicating things such as mechanical dimensions or placement of sensors and actuators. The physical diagram should also be accompanied by a brief one paragraph description.

    • [Subsystem X]

      For each subsystem in your block diagram, you should include a highly detailed and quantitative block description. Each description must include a statement indicating how the block contributes to the overall design dictated by the high-level requirements. Any and all design decisions must be clearly justified. Any interfaces with other blocks must be defined clearly and quantitatively.

      Include any relevant supporting figures and data in order to clearly illustrate and justify the design. Typically a well justified block design will include some or all of the following items: Circuit schematics, simulations, calculations, measurements, flow charts, mechanical diagrams (e.g. CAD drawings, only necessary for mechanical components).

      You must include a Requirements and Verifications table. Please see the R&V page for guidance on writing requirements and verification procedures.

    • [Subsystem Y]

      ...

    • [Subsystem Z]

      ...

    • Tolerance Analysis: Through discussions with your TA, identify the block or interface critical to the success of your project that poses the most challenging requirement. Analyze it mathematically and show that it can be feasibly implemented and meet its requirements. See the Tolerance Analysis guide for further guidance.
  3. Cost and Schedule

    1. Cost Analysis: Include a cost analysis of the project by following the outline below. Include a list of any non-standard parts, lab equipment, shop services, etc., which will be needed with an estimated cost for each.
      • Labor: (For each partner in the project)
        Assume a reasonable salary
        ($/hour) x 2.5 x hours to complete = TOTAL
        Then total labor for all partners. It's a good idea to do some research into what a graduate from ECE at Illinois might typically make.
      • Parts: Include a table listing all parts (description, manufacturer, part #, quantity and cost) and quoted machine shop labor hours that will be needed to complete the project.
      • Sum of costs into a grand total
    2. Schedule:

      Include a time-table showing when each step in the expected sequence of design and construction work will be completed (general, by week), and how the tasks will be shared between the team members. (i.e. Select architecture, Design this, Design that, Buy parts, Assemble this, Assemble that, Prepare mock-up, Integrate prototype, Refine prototype, Test integrated system).

  4. Discussion of Ethics and Safety:

    1. Expand upon the ethical and safety issues raised in your proposal to ensure they are comprehensive. Add any ethical and safety concerns that arose since your proposal.
    2. Document procedures to mitigate the safety concerns of your project. For example, include a lab safety document for batteries, human/animal interfaces, aerial devices, high-power, chemicals, etc. Justify that your design decisions sufficiently protect both users and developers from unsafe conditions caused by your project.
      Projects dealing with flying vehicles, high voltage, or other high risk factors, will be required to produce a Safety Manual and demonstrate compliance with the safety manual at the time of demo.
  5. Citations:

    Any material obtained from websites, books, journal articles, or other sources not originally generated by the project team must be appropriately attributed with properly cited sources in a standardized style such as IEEE, ACM, APA, or MLA.

Submission and Deadlines

Your design review document should be uploaded to PACE in PDF format by the deadline shown on the course calendar . If you have uploaded a mock DR document to PACE, please make sure that it has been removed before DR.

Monitor for Dough and Sourdough Starter

Jake Hayes, Abhitya Krishnaraj, Alec Thompson

Monitor for Dough and Sourdough Starter

Featured Project

Team Members:

- Jake Hayes (jhayes)

- Abhitya Krishnaraj (abhitya2)

- Alec Thompson (alect3)

# Problem

Making bread at home, especially sourdough, has become very popular because it is an affordable way to get fresh-baked bread that's free of preservatives and other ingredients that many people are not comfortable with. Sourdough also has other health benefits such as a lower glycemic index and greater bioavailability of nutrients.

However, the bulk fermentation process (letting the dough rise) can be tricky and requires a lot of attention, which leads to many people giving up on making sourdough. Ideally, the dough should be kept at around 80 degrees F, which is warmer than most people keep their homes, so many people try to find a warm place in their home such as in an oven with a light on; but it's hard to know if the dough is kept at a good temperature. Other steps need to be taken when the dough has risen enough, but rise time varies greatly, so you can't just set a timer; and if you wait too long the dough can start to shrink again. In the case of activating dehydrated sourdough starter, this rise and fall is normal and must happen several times; and its peak volume is what tells you when it's ready to use.

# Solution

Our solution is to design a device with a distance sensor (probably ultrasonic) and a temperature sensor that can be attached to the underside of most types of lids, probably with magnets. The sensors would be controlled with a microcontroller; and a display (probably LCD) would show the minimum, current, and maximum heights of the dough along with the temperature. This way the user can see at a glance how much the dough has risen, whether it has already peaked and started to shrink, and whether the temperature is acceptable or not. There is no need to remove it from its warm place and uncover it, introducing cold air; and there is no need to puncture it to measure its height or use some other awkward method.

The device would require a PCB, microcontroller, sensors, display, and maybe some type of wireless communication. Other features could be added, such as an audible alarm or a graph of dough height and/or temperature over time.

# Solution Components

## Height and Temperature Sensors

Sensors would be placed on the part of the device that attaches to the underside of a lid. A temperature sensor would measure the ambient temperature near the dough to ensure the dough is kept at an acceptable temperature. A proximity sensor or sensors would first measure the height of the container, then begin measuring the height of the dough periodically. If we can achieve acceptable accuracy with one distance sensor, that would be ideal; otherwise we could use 2-4 sensors.

Possible temperature sensor: [Texas Instruments LM61BIZ/LFT3](https://www.digikey.com/en/products/detail/texas-instruments/LM61BIZ%252FLFT3/12324753)

Proximity sensors could be ultrasonic, infrared LED, or VCSEL.\

Ultrasonic: [Adafruit ULTRASONIC SENSOR SONAR DISTANCE 3942](https://www.digikey.com/en/products/detail/adafruit-industries-llc/3942/9658069)\

IR LED: [Vishay VCNL3020-GS18](https://www.mouser.com/ProductDetail/Vishay-Semiconductors/VCNL3020-GS18?qs=5csRq1wdUj612SFHAvx1XQ%3D%3D)\

VCSEL: [Vishay VCNL36826S](https://www.mouser.com/ProductDetail/Vishay-Semiconductors/VCNL36826S?qs=d0WKAl%252BL4KbhexPI0ncp8A%3D%3D)

## MCU

An MCU reads data from the sensors and displays it in an easily understandable format on the LCD display. It also reads input from the user interface and adjusts the operation and/or output accordingly. For example, when the user presses the button to reset the minimum dough height, the MCU sends a signal to the proximity sensor to measure the distance, then the MCU reads the data, calculates the height, and makes the display show it as the minimum height.

Possible MCU: [STM32F303K8T6TR](https://www.mouser.com/ProductDetail/STMicroelectronics/STM32F303K8T6TR?qs=sPbYRqrBIVk%252Bs3Q4t9a02w%3D%3D)

## Digital Display

- A [4x16 Character LCD](https://newhavendisplay.com/4x16-character-lcd-stn-blue-display-with-white-side-backlight/) would attach to the top of the lid and display the lowest height, current height, maximum height, and temperature.

## User Interface

The UI would attach to the top of the lid and consist of a number of simple switches and push buttons to control the device. For example, a switch to turn the device on and off, a button to measure the height of the container, a button to reset the minimum dough height, etc.

Possible switch: [E-Switch RA1113112R](https://www.digikey.com/en/products/detail/e-switch/RA1113112R/3778055)\

Possible button: [CUI Devices TS02-66-50-BK-160-LCR-D](https://www.digikey.com/en/products/detail/cui-devices/TS02-66-50-BK-160-LCR-D/15634352)

## Power

- Rechargeable Lithium Ion battery capable of staying on for a few rounds of dough ([2000 mAh](https://www.microcenter.com/product/503621/Lithium_Ion_Battery_-_37v_2000mAh) or more) along with a USB charging port and the necessary circuitry to charge the battery. The two halves of the device (top and underside of lid) would probably be wired together to share power and send and receive data.

## (stretch goal) Wireless Notification System

- Push notifications to a user’s phone whenever the dough has peaked. This would likely be an add-on achieved with a Raspberry Pi Zero, Gotify, and Tailscale.

# Criterion For Success

- Charge the battery and operate on battery power for at least 10 hours, but ideally a few days for wider use cases and convenience.

- Accurately read (within a centimeter) and store distance values, convert distance to dough height, and display the minimum, maximum, and current height values on a display.

- Accurately read and report the temperature to the display.

- (stretch goal) Inform the user when the dough has peaked (visual, audio, or app based).

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