Project

# Title Team Members TA Documents Sponsor
43 LeafLink
 Hannah Pushparaj
Hassan Shafi
Praveen Natarajan
 Aniket Chatterjee design_document1.pdf
proposal1.pdf
LeafLink

Team Members:
Praveen Natarajan (pn17)
Hassan Shafi(hashafi2)
Hannah Pushparaj(hsp5)

PROBLEM

Plants need to be watered constantly for them to stay alive. Depending on certain scenarios, this might not always be possible for people to do (ex: going on vacation, forgetting to water, etc). We want a way to automatically water these indoor plants to make them stay alive.

SOLUTION

A standalone device that automatically senses the moisture level of the soil, and deploys a pump that supplies the plant with just the right amount of water to survive. It uses an onboard soil moisture sensor along with a water pump to supply the plant with water.
The device is designed to be reliable and easy to understand. A simple light shows what it’s doing (normal, watering, or needs attention). It also includes basic safety limits so it can’t keep running forever if something goes wrong, and it can warn the user if the water container is empty or if the device isn’t able to pump water properly. The device can store a basic history of when it watered the plant so the user can see that it’s working.
If we have time, we can add a simple companion app. The app would let the user see the current soil moisture, and it would show a log of recent watering. It would also allow the user to trigger a quick manual watering from their phone if needed (for example, after repotting or during a very hot week). The app is optional as the device should work on its own even without it.

Solution Components

Subsystem 1: Control & Processing

This subsystem serves as the central controller. An ESP32 on our custom-designed PCB reads soil moisture sensor data, executes watering logic, and controls the relay module. The PCB integrates power regulation and some basic status indication.
Components:
- ESP32
- Our Custom PCB
- 3.3 V voltage regulator
- Some LEDs and resistors


Subsystem 2: Soil Moisture Sensing
This subsystem measures soil moisture and provides an analog voltage to the ESP32 ADC pin to drive the water delivery system.
Components:
- Capacitive Soil Moisture Sensor


Subsystem 3: Water Delivery & Relay Control
This subsystem allows the ESP32 microcontroller to turn the water pump on and off by using a relay, acting as a switch between the ESP32 and higher voltage water pump. So essentially the ESP32 GPIO will drive the relay input which will switch pump power on and off.
Components:
- 6-12 V DC Water pump
- 5 V single-channel relay module
- External 5 V power supply
- Tubing and water reservoir


Subsystem 4: User Feedback & Safety
This subsystem provides basic visual feedback based on the current state of the Leaflink system and an emergency stop button
Components:
- Status LEDs (different colors for idle, watering, error).
- Red push button (emergency stop, kills power)


Subsystem 5: Wireless Monitoring
We will also have a remote monitoring feature using the ESP32’s built-in Wi-Fi. In this remote monitoring system we will display the real-time soil moisture readings (maybe even keep track of old readings over a time period), history of recent watering events, and a manual watering trigger button.
Components:
- ESP32 Wi-Fi (already part of chip)
- Simple mobile or web interface

CRITERION FOR SUCCESS

- The ESP32 on our custom PCB correctly reads soil moisture data and determines when watering is required independently (requiring no supervision)
- Ensure proper functionality of the soil moisture sensor by ensuring moisture readings are accurate (for example if we add water the moisture percentage should get higher)
- The ESP32 reliably controls the relay to turn the water pump on and off based on soil moisture thresholds.
- The water pump operates only through the relay and correctly distributes the required amount of water
- The multiple LEDs correctly indicate the current system states, including idle, watering, and error.
- Pressing the emergency stop button immediately cuts power to the water pump and halts any ongoing operation
- Remote monitoring system displays accurate real-time soil moisture data, logs watering events, and allows manual watering control.

Illini Voyager

Cameron Jones, Christopher Xu

Featured Project

# Illini Voyager

Team Members:

- Christopher Xu (cyx3)

- Cameron Jones (ccj4)

# Problem

Weather balloons are commonly used to collect meteorological data, such as temperature, pressure, humidity, and wind velocity at different layers of the atmosphere. These data are key components of today’s best predictive weather models, and we rely on the constant launch of radiosondes to meet this need. Most weather balloons cannot control their altitude and direction of travel, but if they could, we would be able to collect data from specific regions of the atmosphere, avoid commercial airspaces, increase range and duration of flights by optimizing position relative to weather forecasts, and avoid pollution from constant launches. A long endurance balloon platform also uniquely enables the performance of interesting payloads, such as the detection of high energy particles over the Antarctic, in situ measurements of high-altitude weather phenomena in remote locations, and radiation testing of electronic components. Since nearly all weather balloons flown today lack the control capability to make this possible, we are presented with an interesting engineering challenge with a significant payoff.

# Solution

We aim to solve this problem through the use of an automated venting and ballast system, which can modulate the balloon’s buoyancy to achieve a target altitude. Given accurate GPS positioning and modeling of the jetstream, we can fly at certain altitudes to navigate the winds of the upper atmosphere. The venting will be performed by an actuator fixed to the neck of the balloon, and the ballast drops will consist of small, biodegradable BBs, which pose no threat to anything below the balloon. Similar existing solutions, particularly the Stanford Valbal project, have had significant success with their long endurance launches. We are seeking to improve upon their endurance by increasing longevity from a power consumption and recharging standpoint, implementing a more capable altitude control algorithm which minimizes helium and ballast expenditures, and optimizing mechanisms to increase ballast capacity. With altitude control, the balloon has access to winds going in different directions at different layers in the atmosphere, making it possible to roughly adjust its horizontal trajectory and collect data from multiple regions in one flight.

# Solution Components

## Vent Valve and Cut-down (Mechanical)

A servo actuates a valve that allows helium to exit the balloon, decreasing the lift. The valve must allow enough flow when open to slow the initial ascent of the balloon at the cruising altitude, yet create a tight seal when closed. The same servo will also be able to detach or cut down the balloon in case we need to end the flight early. A parachute will deploy under free fall.

## Ballast Dropper (Mechanical)

A small DC motor spins a wheel to drop [biodegradable BBs](https://www.amazon.com/Force-Premium-Biodegradable-Airsoft-Ammo-20/dp/B08SHJ7LWC/). As the total weight of the system decreases, the balloon will gain altitude. This mechanism must drop BBs at a consistent weight and operate for long durations without jamming or have a method of detecting the jams and running an unjamming sequence.

## Power Subsystem (Electrical)

The entire system will be powered by a few lightweight rechargeable batteries (such as 18650). A battery protection system (such as BQ294x) will have an undervoltage and overvoltage cutoff to ensure safe voltages on the cells during charge and discharge.

## Control Subsystem (Electrical)

An STM32 microcontroller will serve as our flight computer and has the responsibility for commanding actuators, collecting data, and managing communications back to our ground console. We’ll likely use an internal watchdog timer to recover from system faults. On the same board, we’ll have GPS, pressure, temperature, and humidity sensors to determine how to actuate the vent valve or ballast.

## Communication Subsystem (Electrical)

The microcontroller will communicate via serial to the satellite modem (Iridium 9603N), sending small packets back to us on the ground with a minimum frequency of once per hour. There will also be a LED beacon visible up to 5 miles at night to meet regulations. We have read through the FAA part 101 regulations and believe our system meets all requirements to enable a safe, legal, and ethical balloon flight.

## Ground Subsystem (Software)

We will maintain a web server which will receive location reports and other data packets from our balloon while it is in flight. This piece of software will also allow us to schedule commands, respond to error conditions, and adjust the control algorithm while in flight.

# Criterion For Success

We aim to launch the balloon a week before the demo date. At the demo, we will present any data collected from the launch, as well as an identical version of the avionics board showing its functionality. A quantitative goal for the balloon is to survive 24 hours in the air, collect data for that whole period, and report it back via the satellite modem.

![Block diagram](https://i.imgur.com/0yazJTu.png)