ESP32 Wearable Air Quality Pendant with TVOC CO2 Sensor

Wearable air quality pendant uses miniaturized ESP32 (XIAO ESP32C3) with SGP30 TVOC and eCO2 sensor to continuously monitor personal air quality exposure. SGP30 measures: TVOC (0-60000 ppb) and eCO2 (400-60000 ppm). DHT20 compensates for temperature and humidity. Tiny 0.49-inch OLED shows current readings and color-coded health indicator (Green/Yellow/Red). Haptic motor vibrates when TVOC > 1000 ppb (poor air quality warning). Data logged to internal SPIFFS every minute. When near known WiFi AP, automatically uploads data to InfluxDB via HTTP. BLE peripheral mode: paired phone app shows historical exposure graph. Battery: 150mAh LiPo with TP4056, 8-12 hours runtime. Auto screen-off after 30 seconds to save power. Charging via USB-C. 3D printed pendant enclosure. Application: track personal exposure at home, office, gym, commute to identify polluted locations. Libraries: SGP30, Wire, Adafruit_GFX, WiFi, HTTPClient.

Detailed Project Description

ESP32 Wearable Air Quality Pendant with TVOC CO2 Sensor monitors air (or noise) quality in real time and classifies it into readable levels so users can react to unhealthy conditions.

How It Works
1. Gas / particulate / microphone sensors are sampled and calibrated.
2. Values are converted to standard units (ppm, µg/m³, dB) and an index or level (Good / Moderate / Poor).
3. Readings are displayed locally and logged to a dashboard.
4. Alerts are raised when a level becomes unhealthy.

Key Components and Their Role
- ESP32: dual-core Wi-Fi + Bluetooth microcontroller that runs the firmware, reads the sensors and hosts the network connection.
- OLED display (SSD1306): 128x64 I2C display used to show live readings and status.
- Bluetooth Low Energy: short-range low-power wireless link to a phone or browser.
- SGP30: I2C TVOC / eCO2 air-quality sensor.
- Li-ion battery + charger (TP4056): portable power with charge management.

Implementation Steps
1. Collect the components and study each module's datasheet (pin-out, voltage, interface).
2. Wire the circuit on a breadboard following the pin mapping; power sensors from the correct rail (3.3 V / 5 V).
3. Install Arduino IDE, SGP30 Library, Adafruit GFX Library and the required libraries; flash a minimal test sketch for each module separately.
4. Write the main firmware: read sensors → process → drive outputs / send data.
5. Configure network or cloud credentials and test communication end-to-end.
6. Calibrate thresholds, add error handling (reconnect, sensor time-out) and run a long-duration test.
7. Finalise on a PCB / enclosure and document wiring, code and results.

Key Features
- Multi-parameter sensing
- Calibrated readings
- Colour-coded levels
- Cloud logging

Expected Output
On completion the student will have a live air-quality reading with its category and a history chart.

Deliverables
- Complete source code with comments
- Circuit diagram and pin mapping
- Project report with screenshots and results
- Demonstration-ready build