Imported from GitHub: Circuit-Digest/Wearable-Air-Quality-Pendant · commit b142483 · license MIT

Description

The ultra-low power air quality sensor pendant is designed for continuous environmental monitoring in both everyday life and industrial work environments.

README

Wearable Air Quality Pendant 🌬️

A compact, battery-powered wearable device that continuously monitors air quality using TVOC detection. Get real-time feedback about your breathing environment through intuitive LED indicators and audio alerts.

Project Overview

This DIY air quality monitor pendant uses professional-grade sensors to track Total Volatile Organic Compounds (TVOC) in real-time. Perfect for monitoring indoor air quality at home, office, or industrial environments.

Key Features

• Real-time TVOC monitoring using SGP40 sensor
• Ultra-low power design with STM32U083KCU6 microcontroller
• Intuitive feedback - Color-coded LEDs and musical alerts
• Wearable design - Compact 32.5mm diameter pendant
• All-day battery life with efficient power management
• Professional accuracy with industrial-grade sensor

Air Quality Classifications

TVOC Level	Status	LED Color	Audio Alert
0-200	Good	🟢 Green	Soft tone
201-300	Warning	🟡 Yellow	Warning melody
301-500	Alarm	🔴 Red	Urgent beeping
>500	Error	🔴 Flashing Red	Error tone

Hardware Components

Main Components

• STM32U083KCU6 - Ultra-low-power microcontroller
• SGP40-D-R4 - Professional TVOC air quality sensor
• MCP73832T - Li-Po battery charge controller
• ADPL44002 - Low-dropout voltage regulator
• EAST1616RGBA1 - RGB LEDs (4x)
• PKMCS0909E4000-R1 - Piezoelectric buzzer

Power Management

• Li-Po battery charging via USB-C
• Regulated 2.5V supply for stable operation
• Ultra-low power consumption for all-day use

📁 Repository Structure

├── Code/
│   └── Wearable_Air_Quality_Pendant/
│       ├── Wearable_Air_Quality_Pendant.ino
│       └── libraries/
├── PCB/
│   ├── Wearable-Air-Quality-Pendant.kicad_pro
│   ├── Schematic.pdf
│   └── Gerber_Files/
├── 3D_Models/
│   ├── Pendant_Top.stl
│   ├── Pendant_Bottom.stl
│   └── Assembly_Guide.pdf
├── Documentation/
│   ├── Circuit_Diagram.pdf
│   ├── Assembly_Instructions.pdf
│   └── BOM.csv
└── images/

🚀 Quick Start Guide

1. Hardware Assembly

1. Order PCB: Use provided Gerber files
2. Solder components: Follow the detailed BOM
3. 3D print enclosure: Use provided STL files
4. Assemble: Insert PCB into printed enclosure

2. Software Setup

1. Install Arduino IDE (version 1.8.19 or newer)
2. Add STM32 board support
3. Install required libraries:
   • DFRobot_SGP40
   • PlayRtttl
   • ptScheduler
4. Upload firmware using ST-Link programmer

Required Libraries

Add these libraries through Arduino IDE Library Manager:

#include <DFRobot_SGP40.h>     // SGP40 sensor communication
#include <PlayRtttl.hpp>       // Musical tone generation
#include <ptScheduler.h>       // Non-blocking task scheduling

Programming the Device

Hardware Requirements

• ST-Link V2 programmer (required for STM32)
• USB-C cable for power and charging
• 3.3V power supply during programming

Upload Process

1. Connect ST-Link to SWD pins (SWDIO, SWCLK)
2. Select board: "STM32U0 series" in Arduino IDE
3. Select programmer: "STM32CubeProgrammer (SWD)"
4. Upload firmware

PCB Specifications

• Dimensions: 32.5mm diameter
• Layers: 2-layer PCB
• Thickness: 1.6mm
• Components: SMD (0603/0402 packages)
• Connector: USB-C for charging

3D Printing Guide

Print Settings

• Layer Height: 0.2mm
• Infill: 20%
• Supports: Minimal (only for overhangs)
• Material: PLA or PETG recommended

Post-Processing

• Light sanding for smooth finish
• Ensure USB-C port alignment
• Test fit before final assembly

Acknowledgments

• CircuitDigest - Project development and documentation
• DFRobot - SGP40 sensor library
• STMicroelectronics - STM32 microcontroller support
• DigiKey - Sponsors

Support

• Detailed Tutorial: CircuitDigest Article
• Video Guide: YouTube Tutorial
• Issues: Report bugs via GitHub Issues
• Discussion: Join our community forum

Version History

Version	Date	Changes
v1.0	2024-12	Initial release
v1.1	2025-01	Bug fixes, improved battery life

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⭐ If this project helped you, please star the repository!

🔗 Related Projects:

• Arduino Air Quality Monitor
• IoT Air Quality System

📧 Contact: [email protected]