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6 Bluetooth Audio Splitter
Kathryn Fejer
Nathan Narasimhan
Niharika Agrawal
Dhruv Mathur design_document1.pdf
Niharika Agrawal, Kathryn Fejer, Nathan Narasimhan and na13, fejer2, nanaras2

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.

Amphibious Spherical Explorer

Kaiwen Chen, Junhao Su, Zhong Tan

Amphibious Spherical Explorer

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The amphibious spherical explorer (ASE) is a spherical robot for home monitoring, outdoor adventure or hazardous environment surveillance. Due to the unique shape of the robot, ASE can travel across land, dessert, swamp or even water by itself, or be casted by other devices (e.g. slingshot) to the mission area. ASE has a motion-sensing system based on Inertial Measurement Unit (IMU) and rotary magnetic encoder, which allows the internal controller to adjust its speed and attitude properly. The well-designed control system makes the robot free of visible wobbliness when it is taking actions like acceleration, deceleration, turning and rest. ASE is also a platform for research on control system design. The parameters of the internal controller can be assigned by an external control panel in computer based on MATLAB Graphic User Interface (GUI) which communicates with the robot via a WiFi network generated by the robot. The response of the robot can be recorded and sent back to the control panel for further analysis. This project is completely open-sourced. People who are interested in the robot can continue this project for more interesting features, such as adding camera for real-time surveillance, or controller design based on machine learning.

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