Sleep Quality Monitor with Snore Detection using ESP32

Snoring is the most common sleep complaint people actually want measured — "how bad is it, really?" — yet the answer is usually a partner's grumpy estimate. Phone apps exist, but they upload bedroom audio to the cloud and drain the phone. This project takes the embedded route: a sensitive electret microphone with automatic gain control listens all night, an ESP32 analyzes the audio stream in real time for the loud, quasi-periodic bursts characteristic of snoring, and every detected event is timestamped and logged to a microSD card as a small CSV — no audio is stored, only event metadata, so privacy is structural. In the morning the OLED shows a sleep report: total snore events, the loudest episode, the longest quiet stretch, and an estimated sleep-quality score. A single button starts and stops the night, and a real-time clock keeps the timestamps honest across power cycles.

1. The user presses the button at bedtime; the ESP32 starts sampling the MAX9814 microphone output at ~8 kHz into a rolling buffer.
2. Firmware computes short-time energy in 100 ms frames and tracks periodicity — snores show as loud bursts repeating every few seconds.
3. When energy crosses the adaptive threshold with the right burst pattern, an event opens; it closes after 10 seconds of quiet, and is logged with timestamp, duration and peak level.
4. The adaptive threshold slowly follows room background noise, so a fan or air conditioner does not flood the log.
5. At wake-up a long press ends the session; firmware aggregates the night's events into the morning report shown on the OLED.
6. The CSV log on the microSD card accumulates night after night for trend review on a computer.

Tech stack:

• ESP32 dev board
• MAX9814 microphone amplifier + electret mic
• DS3231 RTC · microSD card module
• 0.96 inch OLED display (I2C)
• Pushbutton · 5 V USB power
• Arduino IDE · C/C++ firmware

• [On-device snore detection] Energy-plus-periodicity analysis on the ESP32 flags snore-like bursts in real time — no cloud, no phone, no audio ever leaves the device.
• [Privacy by design] Only event metadata (timestamp, duration, peak level) is logged to microSD; raw audio is processed in RAM and discarded, which the report documents as a design guarantee.
• [Automatic gain control] MAX9814 microphone amplifier with built-in AGC keeps quiet-room sensitivity high without clipping on loud snores.
• [Morning sleep report] OLED summary at wake-up: total events, loudest episode time, longest quiet stretch and a 0–100 sleep-quality estimate from event density.
• [Timestamped CSV logging] Every event lands on the microSD card with date, time, duration and peak level — weeks of data open directly in a spreadsheet for analysis.
• [One-button operation] A single press starts the night session; a long press ends it and shows the report — usable in the dark, half-asleep.
• [RTC timekeeping] DS3231 keeps event timestamps accurate even if the device is unplugged between nights.

• Working sleep monitor prototype (ESP32, microphone module, RTC, SD card, OLED, button)
• Complete firmware source with detection algorithm and report generator
• Wiring diagram and bedside enclosure guidance
• Detection-threshold tuning procedure for the buyer's room
• Project report PDF (background, audio analysis theory, algorithm, testing)
• PPT presentation for final review
• Viva Q&A preparation document (sampling, energy detection, AGC, SD logging)

• Snore detection is heuristic (energy + periodicity), not clinical polysomnography — it estimates snoring activity; it does not diagnose sleep apnea or any medical condition, and the page and report state this plainly.
• Very quiet rooms with loud HVAC can raise the adaptive threshold and miss soft snores; the tuning procedure addresses the buyer's own room.
• The 0–100 sleep-quality score is a simple event-density heuristic for demonstration, not a validated clinical metric — described as such.
• Detection accuracy is not claimed as a measured figure; the report documents the buyer-run validation procedure (annotated test nights) instead.
• One microphone covers one side of the bed; partners' snores in the same room will also be picked up.