Request for Approval

Description

The request for approval (RFA) is the very first step in successfully completing a senior design project. Before submitting your RFA, you must post your project idea to the Web Board using the "Idea" post type. Once your idea has been fleshed out through the Web Board, you can move on request for approval through PACE under the My Project page. Once submitted, your project will be cloned to the Web Board as "Project Request" post. You can edit the project on the My Project page, add your teammates and see comments from the instructors. The course staff may provide feedback on your idea (which will appear at the bottom of your project's page), or suggest changes in the scope of the project and ask you to re-submit an RFA. Based on your incorporation of feedback your project will be approved or rejected. If it is rejected, the My Project page will revert back to it's original format and your project will disappear.

Once the course staff has approved the project idea, you will receive instructions on how to submit your project through PACE, at which time you will be assigned a project number in the Projects list, a TA, and a locker in the lab. Once your project is approved, please go to the Projects page, log into the PACE system, and make sure all of the information is correct.

Video Lecture

Video, Slides

Requirements and Grading

The RFA is graded credit/no credit based on whether your project is approved before the deadline. Note that submitting an RFA before the deadline does not guarantee approval before the deadline. The RFA is submitted through PACE under the My Project page, and should be Markdown-formatted with the following information:

# Title

Team Members:
- Student 1 (netid)
- Student 2 (netid)
- Student 3 (netid)

# Problem

Describe the problem you want to solve and motivate the need.

# Solution

Describe your design at a high-level, how it solves the problem, and introduce the subsystems of your project.

# Solution Components

## Subsystem 1

Explain what the subsystem does.  Explicitly list what sensors/components you will use in this subsystem.  Include part numbers.

## Subsystem 2

## ...

# Criterion For Success

Describe high-level goals that your project needs to achieve to be effective.  These goals need to be clearly testable and not subjective.

Projects must be legal and ethical. They must have significant scope and complexity commensurate with the size of the team. This is, of course, a subjective assessment of the course staff. To gain some insight into this judgment, please browse projects from previous semesters. The project must involve the design of a significant hardware component at the circuit level. In exceptional cases, projects not meeting this criteria may be acceptable when augmented by a Special Circuit assignment (however this is typically a last resort).

Beyond these basic requirements, you have total discretion in proposing a project. This is a great opportunity for you to pursue your own interests. Since you choose your own projects, we expect a high level of enthusiasm from you and your team.

Submission and Deadlines

The RFA submission deadline may be found on the Course Calendar. Typically, approval of the RFA is due during the afternoon of the third Thursday of the semester.

Quick Tips and Helpful Hints

Posting: Choosing a project: Choosing partners: Some general project ideas that are fraught with pitfalls:

Instant Nitro Cold Brew Machine

Danis Heto, Mihir Vardhan

Instant Nitro Cold Brew Machine

Featured Project

# Instant Nitro Cold Brew Machine

Team Members:

- Mihir Vardhan (mihirv2)

- Danis Heto (dheto3)

# Problem

Cold brew is made by steeping coffee grounds in cold water for 12-18 hours. This low-temperature steeping extracts fewer bitter compounds than traditional hot brewing, leading to a more balanced and sweeter flavor. While cold brew can be prepared in big batches ahead of time and stored for consumption throughout the week, this would make it impossible for someone to choose the specific coffee beans they desire for that very morning. The proposed machine will be able to brew coffee in cold water in minutes by leveraging air pressure. The machine will also bring the fine-tuning and control of brewing parameters currently seen in hot brewing to cold brewing.

# Solution

The brew will take place in an airtight aluminum chamber with a removable lid. The user can drop a tea-bag like pouch of coffee grounds into the chamber along with cold water. By pulling a vacuum in this chamber, the boiling point of water will reach room temperature and allow the coffee extraction to happen at the same rate as hot brewing, but at room temperature. Next, instead of bringing the chamber pressure back to atmospheric with ambient air, nitrogen can be introduced from an attached tank, allowing the gas to dissolve in the coffee rapidly. The introduction of nitrogen will prevent the coffee from oxidizing, and allow it to remain fresh indefinitely. When the user is ready to dispense, the nitrogen pressure will be raised to 30 PSI and the instant nitro cold brew can now be poured from a spout at the bottom of the chamber.

The coffee bag prevents the coffee grounds from making it into the drink and allows the user to remove and replace it with a bag full of different grounds for the next round of brewing, just like a Keurig for hot coffee.

To keep this project feasible and achievable in one semester, the nitrogenation process is a reach goal that we will only implement if time allows. Since the vacuum and nitrogenation phases are independent, they can both take place through the same port in the brewing chamber. The only hardware change would be an extra solenoid control MOSFET on the PCB.

We have spoken to Gregg in the machine shop and he believes this vacuum chamber design is feasible.

# Solution Components

## Brewing Chamber

A roughly 160mm tall and 170mm wide aluminum chamber with 7mm thick walls. This chamber will contain the brew water and coffee grounds and will reach the user-set vacuum level and nitrogenation pressure if time allows. There will be a manually operated ball valve spout at the bottom of this chamber to dispense the cold brew once it is ready. The fittings for the vacuum hose and pressure sensor will be attached to the screw top lid of this chamber, allowing the chamber to be removed to add the water and coffee grounds. This also allows the chamber to be cleaned thoroughly.

## Temperature and Pressure Sensors

A pressure sensor will be threaded into the lid of the brewing chamber. Monitoring the readings from this pressure sensor will allow us to turn off the vacuum pump once the chamber reaches the user-set vacuum level. A temperature thermocouple will be attached to the side of the brewing chamber. The temperature measured will be displayed on the LCD display. This thermocouple will be attached using removable JST connectors so that the chamber can be removed entirely from the machine for cleaning.

## Vacuum Pump and Solenoid Valve

An oilless vacuum pump will be used to pull the vacuum in the brewing chamber. A solenoid valve will close off the connection to this vacuum pump once the user-set vacuum pressure is reached and the pump is turned off. To stay within the $100 budget for this project, we have been given a 2-Stage 50L/m Oil Free Lab Vacuum Pump on loan for this semester. The pump will connect to the chamber through standard PTFE tubing and push-fit connectors

If time allows and we are able to borrow a nitrogen tank, an additional solenoid and a PTFE Y-connector would allow the nitrogen tank to connect to the vacuum chamber through the same port as the vacuum pump.

## LCD Display and Rotary Encoder

The LCD display allows the user to interact with the temperature and pressure components of the brewing chamber. This display will be controlled using a rotary encoder with a push button. The menu style interface will allow you to control the vacuum level and brew time in the chamber, along with the nitrogenation pressure if time allows. The display will also monitor the temperature of the chamber and display it along with the time remaining and the current vacuum level.

# Criterion For Success

- A successful cold brew machine would be able to make cold brew coffee at or below room temperature in ten minutes at most.

- The machine must also allow the user to manually control the brew time and vacuum level as well as display the brew temperature.

- The machine must detect and report faults. If it is unable to reach the desired vacuum pressure or is inexplicably losing pressure, the machine must enter a safe ‘stop state’ and display a human readable error code.

- The reach goal for this project, not a criterion for success, would be the successful nitrogenation of the cold brew.

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