Project

# Title Team Members TA Documents Sponsor
6 Bluetooth Audio Splitter
Kathryn Fejer
Nathan Narasimhan
Niharika Agrawal
Dhruv Mathur design_document1.pdf
design_document2.pdf
design_document3.pdf
design_document5.pdf
final_paper1.pdf
proposal1.pdf
proposal2.pdf
proposal3.pdf
Niharika Agrawal, Kathryn Fejer, Nathan Narasimhan and na13, fejer2, nanaras2

Problem:
In order to share in a listening experience, two people would need to either play the audio out loud, perhaps disturbing others such as on the plane, or acquire two pairs of wired headphones and an eighth inch cord splitter. Currently Bluetooth 5, a new Bluetooth protocol, allows for this, but only with common platforms. Such as, you can connect two pairs of Apple headphones to an IPhone, but not a pair of AirPods and a pair of Sony headphones.

Solution Overview:
Create a bluetooth splitter that can take in a bluetooth audio signal and repeat it to multiple bluetooth outputs in order to connect multiple people to one device, wirelessly. We would have a bluetooth receiver and two or more bluetooth transmitter. Most of the similar products on the market have an aux cord to the device playing the audio, but it would be easier for the user if that cord was eliminated. Our device would be platform-independent, such that you can connect a pair of Sony and a pair of Bose headphones to the same phone.

Solution Components:
Subsystem 1: Computer to Bluetooth receiver
This subsystem will connect the computer to the bluetooth receiver. It will also transfer the music data to the other two bluetooth devices. Lastly, this device will also help pair the other two devices to the respective headphones. This will use a microcontroller chip and a bluetooth chip.

Subsystem 2: Bluetooth to Headphone 1 receiver
This subsystem will connect a bluetooth chip with the first set of headphones. This will primarily consist of the bluetooth chip and a button. Initial pairing and setup will be done through a serial monitor and AT commands.

Subsystem 3: Bluetooth to Headphone 2 receiver
This subsystem will connect the other bluetooth chip with the second set of headphones. This will primarily consist of the bluetooth chip and a button. Initial pairing and setup will be done through a serial monitor and AT commands.

Subsystem 4: Micro
We will use a microcontroller chip (for example, an ATmega328P) on a PCB to connect the bluetooth chips and control the input and output from each chip. We would use chips like the HC-05 or 06 which allows us to interface with a microcontroller to allow for pairing and sending of audio. If needed, we could include something akin to a microSD card for buffering or memory.

One concern brought up in office hours was connecting multiple Bluetooth chips to a single Arduino. However, there are two ways to ensure we can send data simultaneously. One, we could use a ATmega328P and connect the Bluetooth chips to the PWM pins and make serial input/outputs. Or, we can use a ATmega2560 chip. This has four hardware communication RX/TX pins, and therefore we could connect three Bluetooth chips here and be able to transmit and receive data reliably.

Subsystem 5: Power
Our microcontroller and PCB will be connected to a battery pack and will then supply power to the bluetooth chips. The chips are 3.3V, therefore we will have voltage dividers to supply the proper power to these chips.

Criteria for Success:
Successful pairing between the computer with our device, and then subsequent pairing with the two seperate bluetooth subsystems with the two seperate devices such that the data sent by the computer is able to be received by the two end devices.

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)