Project

# Title Team Members TA Documents Sponsor
42 Autonomous Cold Salad Bar
Siddhaarta Venkatesh
Tejas Alagiri Kannan
proposal1.jpeg
# **Team:**

1. Tejas Alagiri Kannan(tejasa4)
2. Siddhaarta Venkatesh(sv39)

# **Problem:**
In the food industry, a huge number of processes are extremely rote and utilize manpower on monotonic tasks that can be replaced by an autonomous system. One such problem is the usage of manpower in assembly line format restaurants(eg, Chipotle, Forage Kitchen, Qdoba, etc.). Just as in the automation industry, where the assembly line is, in essence, replaced by 6-DoF arms and robot operators, I believe the manpower in restaurants can also be replaced by a robotic system that can provide higher efficiency. We have already seen a large number of processes getting automated in the restaurant industry, such as the automated food bar in sushi restaurants and robotic servers(not widely adapted unfortunately).

# **Solution:**
At the outset, I would like to mention that the solution does not aim to automate the entire pipeline from creating the dish to serving it. To perform highly technical dishes is a different problem in itself. I aim to make the serving process more efficient and reduce wait time. Given the ingredients, such as, chopped chicken, chopped onions, sauces, etc(which i believe is a fair starting point)

Each ingredient will have its own pipe that dispenses one specific type of dish. Once we receive instructions of what food needs to be prepared and the x # of ingredients it needs to dispense and in which order, the bowl on a conveyor belt will move back and forth to fill up with those ingredients. These ingredients are funneled from their own pipes that dispenses the ingredients, one at a time. The final box is then sealed and placed in a shaker which mixes the ingredients and it is served at the end.

# **COMPONENTS:**

# **Subsystem 1: Motion**
The bowl must be moved around the pipes to get filled. This is what we propose:

Conveyor belt: 4 idlers, 2 head pulleys, 1 NEMA 23 motor(or other), 1 gear reducer, 1 motor driver(TB6600)

1 Food storage basket, 5 individual dispensary pipes, 5 servo motors, 1 servo motor PWM controller

The dispensary pipes will be pumping out food using a servo pump filler mechanism where the servo motor will push down on the contents of the pump(in a piston like motion) and squeeze out the food). We will use the ESP32 Microcontroller series

# **Subsystem 2: User Interface**
For initial testing, simple buttons to determine which dish is chosen. The final device will involve a screen, natural interface. The simple buttons will just be regular tactile buttons. and the final screen would be an ST7789 LCD display that will show the user what food has been ordered. It will show the user what options they have chosen for their salad and how to add/remove particular items with a button press

# **Subsystem 3: Food presentation**
We expect to have the final salad, well tossed and provided to the user. So once the bowl is filled which is determined by it passing through the pipes of all its ingredients, the user will close it with a cap. the user will have the choice to have it shaked or not. That feature is an additional button after the food is dispensed. The bowl is then placed in a closed contrapment which simply rotates at high speeds to mix the food. It is a very similar design to regular boba shakers.
Shaker: 1 NEMA 23 motor, 1 gear box, 1 motor driver(TB6600)

# **Subsystem 4: Accuracy checking**
A major part of this project is to ensure efficiency. So we will incorporate a weight sensor(mini load cell), this weight sensor will track the weight of the bowl as items are being dispensed and will serve as a checker to stop the machine from over dispensing.

# **Subsystem 5: Power system**
For demonstration purposes the machine will be hooked up to a benchtop powersupply or another reliable form of powersupply similar to a benchtop like a low-grade DC power supply.

Another main component that we will add is food safe tubing to ensure that the food does not get contaminated

# **Criterions for success:**
1. The conveyor belt is able to move consistently in a way that the bowl is under the right dispenser.
2. Each dispenser is able to dispense food. This would be for both solid and liquid food, such as sauces.
3. Each dispenser is able to dispense the right amount of food or a range of food in a set range.
4. Initial prototype can, on button press, determine exact motor angles to move the components for early demo during semester
5. Final prototype can, on user request, send a signal to the microprocessor to move bowl and dispense mock food into a bowl.

# **Team work requirements:**

1. CAD every individual component in a miniature form to depict the real system (1 week)
2. Use Dev board with motor drivers to demonstrate bread board working of Criterion 1 of success. (1 week)
3. Attach devboard solution to CAD physical model to take into account motor backlash and other physical constraints like power supply issues and overheating ( 1 week)
4. Start PCB design based on the chosen direction. Soldering and debugging (3-4 weeks)
5. Final assembly and testing( 1 week)
This gives us maybe 1 week of extra leeway for any hindrances.

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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