Project

# Title Team Members TA Documents Sponsor
3 Smart Interface for ECEB Research Solar Panels
Texas Instruments Best Project Award
 Dillon Vadgama
Douglas Lee
Sachin Reddy
 Shaoyu Meng design_document3.pdf
final_paper1.pdf
presentation1.pdf
proposal1.pdf
video
# Problem

In 2018, a fire broke out on the roof of a Walmart in Beavercreek, Ohio due to Tesla’s unmaintained solar panels suffering from hotspots. These hotspots resulted in the cracking of the back sheets of the solar modules and compromising their electrical insulation. There was no protection system to detect this type of unwanted behavior and shut down the system before a fire broke out. As a result, Walmart sued Tesla over the flaws present in their solar panels.

Our very own ECE Building has a roof of 60 solar panels used for research; however, there are no protection interfaces between the solar panels and their connections to the power inverter. A smart interface box attached to each solar panel that monitors system behavior and has the ability to shut off the entire operation could help prevent a disaster like Walmart’s.

This project was initially pitched by Professor Arijit Banerjee and generated interest from several students. After a meeting with Professor Banerjee and David Null, two teams working on two separate projects related to the ECEB solar panels were created. It was decided that our group (Dillon Vadgama, Doug Lee, and Sachin Reddy) will be working on the Smart Interface Box for the ECEB research panels. The other students will be working on another project relating to the set of solar panels providing the building with power.


# Solution Overview

Our solution for monitoring and controlling our solar panels will be a smart interface box mounted directly to the solar panel. Electrically, the interface box will be connected directly to the output of the solar panel and will have the ability to configure how many cells will be connected to the power inverter (32 cells, 64 cells, or 128 cells). The system will be powered from an isolated 12V supply and an Ethernet interface will allow users to configure and monitor the solar panel through a server/PC. Because the power generated by the solar panel will be running through the smart interface box, we will have the ability to detect overcurrent/overvoltage conditions and disconnect the solar panel if necessary. Lastly, connections on the interface box will be available to attach thermocouples. Doing so will allow us to measure temperatures on different parts of the solar panel and disconnect the solar panel to prevent a hotspot disaster.

The interface box will have the following key features:
- The output of the interface will be configurable to be connected to either 32 cells, 64 cells, or 128 cells.
- The output of the interface box will be protected from overvoltage and overcurrent.
- An onboard microprocessor will allow for communication and measurement of system parameters over an ethernet connection.
- The box will be powered from an isolated 12V PSU.
- Should the 12V power supply fail, the output of the interface will be disconnected from the solar panel.
- Onboard LEDs will indicate the operational status of the panel and interface.
- When the system is not communicating via Ethernet, the configuration of the interface can be controlled manually via onboard - switches.
- The enclosure of the interface will be weather-proof along with any cable jacks used.
- An option to integrate thermocouples with the system will be available.


# Solution Components

## Switching Subsystem

- Contains switching components responsible for connecting different sections of the solar panel (32 cells, 64 cells, or 128 cells) to the output or disconnecting the solar panel altogether.
- The switching configuration will be controlled by the Processing Subsystem.

## Electrical Monitoring Subsystem

- Connects directly to the output of the switching subsystem and is responsible for measuring current and voltage.
- The subsystem has two outputs: one that communicates voltage/current data to the Processing Subsystem and another that passes power generated by the solar panel to the output of the interface box (and into power inverter).

## Temperature Monitoring Subsystem

- Contains all of the circuitry necessary to extract temperature data sourced from thermocouples that will be mounted on various areas of the solar panel.
- This data will be sent to the Processing Subsystem for further analysis.

## Manual Switches

- In case of a loss of connection to the internet and the server is unable to access the interface box, there will be manual switches mounted on the enclosure to control the configuration of the solar panel.
- These switches will not affect the configuration of the solar panel if the Ethernet Interface is in already in use.

## Processing Subsystem

- An internal microcontroller (most likely an ATmega328P) will be used to communicate with and control other subsystems present in the interface box.
- Detects overcurrent/overvoltage conditions using data sent by the Electrical Monitoring Subsystem.
- Detects hotspots and overheating using data sent by the Temperature Monitoring Subsystem.
- Controls the Switching Subsystem to set the output configuration the solar panel or disconnect it altogether if a failure condition is met.
- Packages and sends relevant data and receives configuration commands from the user through the Ethernet Interface.
- Reads the switch states from the Manual Switches to control the configuration of the solar panel if an Ethernet connection has not been established.

## Ethernet Interface

- Facilitates communication via Ethernet between a server/PC and the microcontroller installed in the interface box.
- Allows the command, control, and monitoring of the solar panel to take place.

## LED Display

- Several LEDs will be present to show information about:
-- Whether or not the interface box is active
-- The current configuration of the solar panel, or
-- Whether or not an Ethernet connection is active.

## Power Subsystem

- Regulates the 12V supply into voltage levels suitable to power all of the above subsystems.

## Software

- Receives data output through the Ethernet Interface and stores the information in a database of some sort.
- A python based GUI will be able to extract, transmit commands, and display the data, providing a user-friendly experience.
- Must be Windows compatible.
- Both the database and the GUI should be secured to prevent unauthorized users from controlling the solar panels.


# Criterion for Success

Our solution will be successful if it can accurately monitor a solar panel’s power output and temperature while simultaneously reporting this data to an external server. A GUI type interface should display output data from the interface box and allow the user to configure the solar panel remotely. In the case of a loss of connection to the internet, the interface box will be controlled by built-in buttons on the box. Additionally, the interface box will be a success if it can realize all of the items listed in the Key Features section above.

We aim to build a weather-proof device that can use an Ethernet LAN connection to then access a server where a user can check how the solar panels are doing at any given time. The end goal is to provide a fully functional prototype for the ECE department to use on one solar panel. With time and some refinement to the design, multiple interface boxes will be manufactured and installed on each of the ECEB research panels.


# Team Members

- Dillon Vadgama (dvadga2)
- Douglas Lee (dlee242)
- Sachin Reddy (ssreddy2)

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).

Project Videos