Project

# Title Team Members TA Documents Sponsor
18 Acoustic Stimulation to Improve Sleep
Bakry Abdalla
John Ludeke
Sid Gurumurthi
Mingrui Liu design_document1.pdf
proposal1.pdf
Sound Sleep
# Acoustic Stimulation to Improve Sleep

Team Members:
- Abdalla, Bakry (bakryha2)
- Gurumurthi, Sid (sguru2)
- Ludeke, John (jludeke2)

# Problem

Certain people experience poor quality sleep as they age or develop sleep disorders because they do not spend enough time in slow wave sleep (SWS). While there are data-first solutions currently available to the public, they are expensive.

# Solution

Closed-loop auditory simulation has been shown through research to amplify the oscillations of SWS. When it is time to sleep, users will put a wearable device on their head. The device will consist of an EEG headband with dry electrodes to measure brain activity which will be connected to an all-purpose, custom PCB that integrates the EEG front-end, microcontroller, audio driver, and power management circuitry.

The processor detects slow wave sleep and identifies slow wave oscillations. When these waves are detected, the system delivers short, precisely timed bursts of pink noise through an integrated speaker. Data insights about the user’s sleep patterns are delivered via a user-facing application.

All of this while being cheaper than what is currently available.

# Solution Components

## Subsystem 1 – EEG Headband

We will be using a commercially available EEG Headband, the OpenBCI EEG Headband Kit. This includes the headband, electrodes, and cables carrying the analog signal.

Components:
- OpenBCI EEG Headband: https://shop.openbci.com/products/openbci-eeg-headband-kit
- Ag-AgCl Electrodes
- Earclip & snap cables

## Subsystem 2 – Signal Processor

Takes in analog signals, denoises and amplifies, digitally processes, and then outputs.
The signal processing subsystem is responsible for performing the core functionality of a commercial EEG interface such as the OpenBCI Cyton, but at a lesser cost. It receives raw analog EEG signals from the headband electrodes and converts them into digitized, clean EEG data suitable for downstream analysis. It would perform amplification of weak analog electric signals followed by analog filtering to limit bandwidth to EEG-relevant bands and prevent aliasing before analog-to-digital conversion. Following digitization, the subsystem performs digital signal processing, including bandpass and notch filtering, for noise and artifact reduction. An accelerometer would be incorporated to remove spikes and noise in EEG data at significant motion events.

Components:
- Analog front end: Texas Instruments ADS1299
- Microcontroller: PIC32MX250F128B
- Wireless transmission of data: RFduino BLE radio module (RFD22301)
- Triple-Axis Accelerometer: LIS3DH
- Resistors: COM-10969 (ECE Supply Store)
- Capacitors: 75-562R5HKD10, 330820 (ECE Supply Store)
- JFET Input Operational Amplifier: TL082CP (ECE Supply Store)
- Standard Clock Oscillators 2.048MHz: C3291-2.048

## Subsystem 3 – Audio Output

After receiving the processed audio signals from the signal processor's subsystem, this subsystem will provide the data as input to an algorithm which decides whether or not to play a certain frequency of noise through the preferred audio output device (default will be speaker). The algorithm makes this decision by detecting whether the brain signals indicate short wave sleep is occurring.

Components:
- A special algorithm to detect short wave sleep (https://pubmed.ncbi.nlm.nih.gov/25637866/)
- One small integrated speaker (665-AST03008MRR)

## Subsystem 4 – Power Delivery

To provide power for the entire system, a power circuit is integrated into the PCB. This circuit manages battery charging and voltage regulation while minimizing heat dissipation for user comfort.

Components:
- 2 AAA batteries: EN92
- Voltage regulator: LM350T
- Capacitors: 75-562R5HKD10
- On/off switch: MULTICOMP 1MS3T1B1M1QE
- Power jack: 163-4013

## Subsystem 5 – User-Facing Application

To improve usability, the User-Facing Application will give the end user insights into their sleep using standard sleep metrics. Specifically, it will tell the user their time spent not sleeping, in REM sleep, light sleep, and deep sleep.

We can use a React Native frontend for compatibility with Android and iOS. We can run a lightweight ML model on-device with Python to determine the state of sleep (using libraries like FFT and bandpower). For the backend, Firebase can be used to store our data, which will come in via Bluetooth.

Components:
- React Native
- Firebase

# Criterion For Success

- Headset remains comfortable (4/5 people would be okay wearing the device to sleep)
- Signal Processor successfully amplifies and denoises signal
- Signal Processor successfully converts the analog signal into a digital one
- Audio Output gives audio in phase with EEG waves to maximize effectiveness
- Audio Output correctly adjusts audio in correspondence to the input signal from the Signal Processor
- Power Delivery gives enough battery power for the device to last at least 10 hours
- Power Delivery remains cool and comfortable for sleep
- User-Facing Application is intuitive (4/5 people would download the app)
- User-Facing Application shows accurate, historical data from the user’s headband
- User-Facing Application correctly classifies phases of the user’s sleep
- The entire system is easy to use (a new user can figure it out without instruction)
- The entire system works seamlessly

Master Bus Processor

Clay Kaiser, Philip Macias, Richard Mannion

Master Bus Processor

Featured Project

General Description

We will design a Master Bus Processor (MBP) for music production in home studios. The MBP will use a hybrid analog/digital approach to provide both the desirable non-linearities of analog processing and the flexibility of digital control. Our design will be less costly than other audio bus processors so that it is more accessible to our target market of home studio owners. The MBP will be unique in its low cost as well as in its incorporation of a digital hardware control system. This allows for more flexibility and more intuitive controls when compared to other products on the market.

Design Proposal

Our design would contain a core functionality with scalability in added functionality. It would be designed to fit in a 2U rack mount enclosure with distinct boards for digital and analog circuits to allow for easier unit testings and account for digital/analog interference.

The audio processing signal chain would be composed of analog processing 'blocks’--like steps in the signal chain.

The basic analog blocks we would integrate are:

Compressor/limiter modes

EQ with shelf/bell modes

Saturation with symmetrical/asymmetrical modes

Each block’s multiple modes would be controlled by a digital circuit to allow for intuitive mode selection.

The digital circuit will be responsible for:

Mode selection

Analog block sequence

DSP feedback and monitoring of each analog block (REACH GOAL)

The digital circuit will entail a series of buttons to allow the user to easily select which analog block to control and another button to allow the user to scroll between different modes and presets. Another button will allow the user to control sequence of the analog blocks. An LCD display will be used to give the user feedback of the current state of the system when scrolling and selecting particular modes.

Reach Goals

added DSP functionality such as monitoring of the analog functions

Replace Arduino boards for DSP with custom digital control boards using ATmega328 microcontrollers (same as arduino board)

Rack mounted enclosure/marketable design

System Verification

We will qualify the success of the project by how closely its processing performance matches the design intent. Since audio 'quality’ can be highly subjective, we will rely on objective metrics such as Gain Reduction (GR [dB]), Total Harmonic Distortion (THD [%]), and Noise [V] to qualify the analog processing blocks. The digital controls will be qualified by their ability to actuate the correct analog blocks consistently without causing disruptions to the signal chain or interference. Additionally, the hardware user interface will be qualified by ease of use and intuitiveness.

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