Project

# Title Team Members TA Documents Sponsor
25 CUSTOM MPPTS FOR ILLINI SOLAR CAR
 Akhil Pothineni
Alex Chmiel
Alex Lymberopoulos
 Matthew Qi design_document1.pdf
design_document2.pdf
final_paper1.pdf
photo1.jpeg
photo2.jpg
photo3.jpg
presentation1.pdf
proposal2.pdf
proposal1.pdf
video
 Illini Solar Car
# CUSTOM MPPTS FOR ILLINI SOLAR CAR

Team Members:
- Alex Chmiel (achmiel4)
- Alex Lymberopoulos (alexdl2)
- Akhil Pothineni (akhilp3)

# Problem

Illini Solar Car is manufacturing their 3rd generation vehicle to race at the American Solar Challenge this coming summer. The team has recently installed their array and is looking for easy-to-use, configurable, and efficient solar MPPTs. The off-the-shelf models are very expensive and will take time to integrate into the vehicle’s architecture. Also with off-the-shelf components if a part fails, we will not have access to the schematics to replace the component.

# Solution

The idea is to create custom, efficient, and low cost MPPTs built for the team’s electrical system. For some background, the vehicle has the array wired in three separate sections. The goal behind the 3 sections is better resilience to shading and redundancy built into the system. We would make an easy to move enclosure with three MPPTs inside that can be mounted in the vehicle. If one of the MPPTs fails we would still have 2/3 of the solar array producing power.

By making the MPPTs in house lots of problems could be solved. We could drastically reduce the cost, make it plug-and-play with our vehicle’s electrical systems, and be able to debug issues quickly.

# Solution Components

## Subsystem 1: Logic Board

This board will be running a perturb and observe algorithm to vary switching signals sent to an off-board power board.
- LPC1549: Microcontroller used in all solar car projects. Has built in CAN controllers. Data will be sent over CAN.
- Voltage Sensors: To view the voltage and vary the algorithm. Most likely use SPI communication protocol.
- Current Sensors: To view the current and vary the algorithm. Most likely use SPI communication protocol.
- Temperature Sensors: Monitor Temperature of the MPPTs to verify safe operating points.
- Fans Control: Turn on the fan when temperatures get too hot.
## Subsystem 2: Power Board

The power board will be controlled by the logic board to take in the input power and vary the output power to charge the battery. Should handle power up to ~900W. MPPTs should be able to output in the range of 77V-120V. Max charge current is ~2.75A.
- Boost Converter Circuit: Will boost input voltage to charge battery safely. Takes input from logic board.

# Criterion For Success

- Logic Board is able to read temperature and vary fans

- Logic Board is able to send information via CAN

- Power Board successfully boost input voltage

- If faults are induced the logic board is able to stop charging of the batteries.

- Create one logic board that can control one power board to follow a perturb and observe algorithm.

UV Sensor and Alert System - Skin Protection

Liz Boehning, Gavin Chan, Jimmy Huh

UV Sensor and Alert System - Skin Protection

Featured Project

Team Members:

- Elizabeth Boehning (elb5)

- Gavin Chan (gavintc2)

- Jimmy Huh (yeaho2)

# Problem

Too much sun exposure can lead to sunburn and an increased risk of skin cancer. Without active and mindful monitoring, it can be difficult to tell how much sun exposure one is getting and when one needs to seek protection from the sun, such as applying sunscreen or getting into shady areas. This is even more of an issue for those with fair skin, but also can be applicable to prevent skin damage for everyone, specifically for those who spend a lot of time outside for work (construction) or leisure activities (runners, outdoor athletes).

# Solution

Our solution is to create a wristband that tracks UV exposure and alerts the user to reapply sunscreen or seek shade to prevent skin damage. By creating a device that tracks intensity and exposure to harmful UV light from the sun, the user can limit their time in the sun (especially during periods of increased UV exposure) and apply sunscreen or seek shade when necessary, without the need of manually tracking how long the user is exposed to sunlight. By doing so, the short-term risk of sunburn and long-term risk of skin cancer is decreased.

The sensors/wristbands that we have seen only provide feedback in the sense of color changing once a certain exposure limit has been reached. For our device, we would like to also input user feedback to actively alert the user repeatedly to ensure safe extended sun exposure.

# Solution Components

## Subsystem 1 - Sensor Interface

This subsystem contains the UV sensors. There are two types of UV wavelengths that are damaging to human skin and reach the surface of Earth: UV-A and UV-B. Therefore, this subsystem will contain two sensors to measure each of those wavelengths and output a voltage for the MCU subsystem to interpret as energy intensity. The following sensors will be used:

- GUVA-T21GH - https://www.digikey.com/en/products/detail/genicom-co-ltd/GUVA-T21GH/10474931

- GUVB-T21GH - https://www.digikey.com/en/products/detail/genicom-co-ltd/GUVB-T21GH/10474933

## Subsystem 2 - MCU

This subsystem will include a microcontroller for controlling the device. It will take input from the sensor interface, interpret the input as energy intensity, and track how long the sensor is exposed to UV. When applicable, the MCU will output signals to the User Interface subsystem to notify the user to take action for sun exposure and will input signals from the User Interface subsystem if the user has put on sunscreen.

## Subsystem 3 - Power

This subsystem will provide power to the system through a rechargeable, lithium-ion battery, and a switching boost converter for the rest of the system. This section will require some consultation to ensure the best choice is made for our device.

## Subsystem 4 - User Interface

This subsystem will provide feedback to the user and accept feedback from the user. Once the user has been exposed to significant UV light, this subsystem will use a vibration motor to vibrate and notify the user to put on more sunscreen or get into the shade. Once they have done so, they can press a button to notify the system that they have put on more sunscreen, which will be sent as an output to the MCU subsystem.

We are looking into using one of the following vibration motors:

- TEK002 - https://www.digikey.com/en/products/detail/sparkfun-electronics/DEV-11008/5768371

- DEV-11008 - https://www.digikey.com/en/products/detail/pimoroni-ltd/TEK002/7933302

# Criterion For Success

- Last at least 16 hours on battery power

- Accurately measures amount of time and intensity of harmful UV light

- Notifies user of sustained UV exposure (vibration motor) and resets exposure timer if more sunscreen is applied (button is pressed)