Project :: ECE 445 - Senior Design Laboratory

#	Title	Team Members	TA	Documents	Sponsor
23	Drink Dispensing Robot	Andrew Jung Ethan Cao Megan Cheng
	# Title - Drink Dispensing Robot Team Members: - Andrew Jung (crjung2) - Ethan Cao (ecao4) - Megan Cheng (mxcheng2) # Problem Too often, we’re tired or distracted and put off getting a drink of water. Those small delays add up, leaving us dehydrated and drained without even realizing it. Dehydration impacts focus, energy, and overall well-being, yet it happens so easily in our daily lives. # Solution Describe your design at a high level, how it solves the problem, and introduce the subsystems of your project. It solves the problem by creating an ecosystem that allows a delivery system to a drink dispenser hub and then delivers back to the user. This will include a Robot with the ability to detect where the hub is and the cup is, a Hub with the ability to dispense two different liquids, and a Callback system that allows the user to call for the robot to come and pick up the cup. # Solution Components Explain what the subsystem does. Explicitly list what sensors/components you will use in this subsystem. Include part numbers. ## Shared Circuits ### Brushed motor driver We will be using some H-bridge driver IC, such as the DRV8841, to drive 2 sensored brushed motors We may want a small filtering circuit to reduce motor EMI ### Battery We will run off of 9V batteries ## Subsystem 1 - Robot ### Chassis: Mechanical part The robot will be a 3d printed 2-wheel drive chassis, which has 1 directly driven wheel on each side and a caster wheel ### Microcontroller + networking: compute the robot’s next action and communicate the system state to the other components ESP32S3 ### Drive We will use the same brushed motor driver as the rest of the system ### Locating callback system The robot will use an IR receiver to track the cup’s position ### Locating hub The robot will use an IR sensor to align with the hub. This will be done by doing an ~45 degree sweep in the direction of the hub and aligning with the point that has the peak IR brightness ### Cliff detection Use a distance sensor (QRE1113) to detect that there is a solid surface in front of the wheels ## Subsystem 2 - Drink Dispenser Hub The goal of this subsystem is to detect when the robot is underneath the nozzle. It will do that by emitting a general UWB, but then use IR to line up the robot precisely so that it will be under the drink system. After that occurs, it should be able to take the information from the callback system. With that information read it should be able to dispense the two liquids using a pump system. [Pump System](https://www.amazon.com/Diitao-Peristaltic-Connector-Aquarium-Analytic/dp/B0BB7KFRKJ?crid=13GKYIT7C5X5X&dib=eyJ2IjoiMSJ9.s470H6yLkoemv4HuZ9lGLwZZQg-a_7MaLY_vcFxsowj5uvlEs7obqDJx-53UV37HiWg79Pkrj576_HDzT428oA_280tYnCqexlKI3pO3ZotaWuM075bNYiPOxzd1x4JhxHi5UM6kKTd4PKZEg51rS35Ewz0Rh-Crd9eG6nivk_F9K1JjMHt19liiAfUJT_apBCN1mF6IYqDccJk0CRmCsa__1T9RhZ5zQPhhA30Hvfc.mMJwUXJHLF-ti6JAseRkx5ba7VYwh5UWYCvrFA506iY&dib_tag=se&keywords=peristaltic%2Bpump&qid=1756915929&sprefix=perstatic%2Caps%2C100&sr=8-14&th=1) Emit UWB [ESP32S3 ](https://www.digikey.com/en/products/detail/espressif-systems/ESP32-S3-WROOM-1-N4R8/16163965) Precision Docking (IR) [IR Transmitter](https://www.sparkfun.com/infrared-emitter.html) [IR Reciever](https://www.sparkfun.com/ir-receiver-diode-tsop38238.html) Robot Arrived Check Bumper with a button on it Space bar on a keyswitch (We have both of these already) ## Subsystem 3 - Callback System (Cup) [ESP32S3 to communicate](https://www.digikey.com/en/products/detail/espressif-systems/ESP32-S3-WROOM-1-N4R8/16163965) Precision Docking (IR) Communicates with the User input (Drink Ratio) Button Pressed -> Ready to send Dial (Water & Mixer) (RV4NAYSD101A) Gives the ratio of water and mixer # Criterion For Success The robot shall be able to locate the cup and retrieve it from the user on demand. The robot shall detect that the user has placed the cup on top of the robot and return to the dispenser hub The dispenser will refill the cup with a mixture of 2 liquids at a ratio defined by the user The robot will return to where it retrieved the cup from. This is done on a flat tabletop with no obstructions. But the robot will avoid falling off of the table

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.

Project Videos

Team 4 Video Demonstration