Description

Imported from GitHub: Ans1S/esp32-c3-iot-sensor-board · commit 487b68a · license MIT

Description

Open-source ESP32-C3 platform for ultra-low-power environmental sensor networks powered by recycled LiPo cells. Includes KiCad PCB, PlatformIO firmware (ESP-NOW + ThingSpeak), BME280/BME680 support, deep-sleep optimizations and measured >12 months runtime on typical cells.

README

🔋 lil-ESP32-C3

Compact ESP32-C3 IoT Board with Sustainable Battery Recycling

Features • Hardware • Software • Getting Started • Documentation

📖 Overview

A complete open-source hardware and software solution for building ultra-low-power IoT sensor networks using the ESP32-C3 microcontroller. This project transforms discarded vape batteries into sustainable power sources for distributed environmental monitoring systems.

🎯 Key Features

♻️ Sustainable & Eco-Friendly

Recycle discarded vape batteries
Prevent e-waste, extend battery life
Second life for 300-900mAh LiPo cells

📡 Ultra-Low Power Design

ESP-NOW wireless protocol
Deep sleep: ~10µA consumption
12+ months on single charge

🌡️ Environmental Monitoring

BME280/BME680 sensor support
Temperature, humidity, pressure, IAQ
I2C interface for easy expansion

☁️ Cloud Connected

ThingSpeak integration
Real-time data visualization
Multi-sensor aggregation

💡 Use Case

The system architecture consists of distributed sensor nodes placed throughout your environment, communicating via ESP-NOW to a central hub that aggregates and uploads data to the cloud.

┌─────────────┐     ESP-NOW       ┌──────────────┐     WiFi        ┌────────────┐
│ Sensor Node │ ─────────────────→│  Home        │ ───────────────→│ ThingSpeak │
│ (Battery)   │                   │  Station     │                 │   Cloud    │
└─────────────┘                   │  (USB)       │                 └────────────┘
                                  └──────────────┘
       ↓                                ↑
  Deep Sleep                      Data Queue
  10 minutes                      Buffering

Typical Deployment:

🏠 Living Room: Temperature + Humidity monitoring
🛏️ Bedroom: Air quality (IAQ) tracking
🍳 Kitchen: VOC detection for cooking
🖥️ Office: Climate control optimization
📊 Dashboard: Real-time visualization on any device

� Hardware

Custom ESP32-C3 PCB Design - Version 3

Core Specifications:

Component	Specification
MCU	ESP32-C3 @ 160MHz (RISC-V)
Wireless	WiFi 4 (802.11 b/g/n) + BLE 5.0
Memory	400KB SRAM, 4MB Flash
GPIO	22 programmable pins
ADC	12-bit for battery monitoring
Interface	USB-C for power & programming
PCB	4-layer design for EMI reduction

Power System:

✅ LiPo charging IC (100mA/1A)
✅ Power path controller
✅ 3.3V LDO regulator
✅ Battery protection circuit
✅ USB-C input (5V)
⚠️ No buck-boost converter

Version 3 Improvements:

Enhanced ground plane
Optimized power path
Better thermal management

PCB Evolution: Three design iterations available in PCB/ directory with progressive improvements in power management, I2C connectivity, and EMI shielding.

🌡️ Supported Sensors

All sensors connect via I2C interface (SDA: GPIO5, SCL: GPIO4)

BME280

Climate Monitoring

📊 Temperature ±1°C
💧 Humidity ±3% RH
🌡️ Pressure ±1 hPa
⚡ Ultra-low power (~3.6µA)

Perfect for basic environmental monitoring

BME680

Air Quality Analysis

📊 Temperature ±1°C
💧 Humidity ±3% RH
🌡️ Pressure ±1 hPa
🌬️ IAQ Index (VOC detection)

Ideal for health-conscious monitoring

Why I2C?

Simple 2-wire interface (SDA + SCL)
Multiple sensors on same bus
Standardized protocol
Minimal GPIO usage

🔋 Battery Technology

Sustainable Power: Recycled Vape Batteries

✅ Advantages

♻️ Environmental Impact: Prevents e-waste
💰 Cost-Effective: Free or very cheap
⚡ High Capacity: 300-900mAh tested range
📦 Compact Size: Perfect for IoT devices
🔌 Ready to Deploy: Standard LiPo format

⚠️ Considerations

Safety risk during extraction
Unknown battery health/cycles
Inconsistent capacity by brand
No manufacturer warranty
Requires voltage testing

📊 Real-World Performance

Configuration	Result
Battery	550mAh (recycled vape)
Sensor	ESP32-C3 + BME280
Interval	10 minutes
Runtime	⚡ 12+ months without recharge

💡 Note: Various battery capacities tested (300mAh - 900mAh) with proportional runtime results. Actual performance depends on battery condition and usage pattern.

Safety Guidelines

⚠️ Important: Always follow proper safety procedures

Inspect for physical damage before use
Test voltage (3.0-4.2V acceptable range)
Never use swollen batteries
Use protective equipment during extraction
Dispose of damaged cells properly

🎛️ Power Management System

Intelligent Power Architecture

Components:

1️⃣ USB-C Input

5V programming & charging
Automatic source detection

2️⃣ Charging IC

CC/CV LiPo charging
100mA or 1A variants
4.2V cutoff protection
LED status indicator

3️⃣ Power Path Controller

Seamless USB/battery switching
Load sharing capability
Back-feed prevention

4️⃣ 3.3V LDO Regulator

Efficient voltage regulation
Low dropout design
Stable output for MCU

Protection Features:

🛡️ Over-discharge protection
🛡️ Over-current protection
🛡️ Short-circuit protection
🛡️ Temperature monitoring

Performance:

⚡ Deep sleep: ~10µA
⚡ Active (sensing): ~80mA
⚡ TX (ESP-NOW): ~120mA
⚡ Duration: 2-3 sec/cycle

⚠️ Design Trade-off: No Buck-Boost Converter

Current Implementation (LDO only):

Aspect	Impact
❌ Battery usable range	4.2V → 3.3V only (~75% capacity)
❌ Lost capacity	~25% (below 3.3V unusable)
✅ Circuit complexity	Simple, reliable
✅ Cost	Lower BOM cost
✅ Efficiency	High at normal voltage
✅ Runtime	Still 12+ months achieved

Rationale: The LDO-only design provides sufficient runtime for most use cases while keeping the design simple and cost-effective. Future versions may incorporate buck-boost for maximum battery utilization.

💻 Software Architecture

Five Firmware Implementations for Different Use Cases

1️⃣ ESP32-Sensor

BME280 Basic Node

📍 SW-VSCode/ESP32-Sensor/

Temperature, humidity, pressure
10-min deep sleep cycles
ESP-NOW transmission
3-6 months battery life
Configurable sensor ID

2️⃣ ESP32-Extra-Sensor

BME680 Air Quality

📍 SW-VSCode/ESP32-Extra-Sensor/

IAQ (Indoor Air Quality)
Multi-temp calibration
Professional gas sensing
ESP-NOW with retry
10-min deep sleep

3️⃣ ESP32-Home-Station

Central Hub

📍 SW-VSCode/ESP32-Home-Station/

ESP-NOW receiver
Data queue (20 readings)
Dynamic WiFi
FreeRTOS tasks
ThingSpeak upload
USB-powered

4️⃣ W-Charger-ThingSpeak-1A

WiFi Monitor (1A)

📍 SW-VSCode/W-Charger-ThingSpeak-1A/

Direct WiFi (no ESP-NOW)
Battery monitoring
RSSI reporting
10-min upload interval
Deep sleep
1A charging

5️⃣ W-Charger-ThingSpeak-100mA

Low-Power WiFi

📍 SW-VSCode/W-Charger-ThingSpeak-100mA/

WiFiManager config
Calibrated ADC
ThingSpeak upload
100mA charging
Deep sleep optimized

🚀 Getting Started

Prerequisites

🔧 Hardware Requirements

✅ ESP32-C3 board (custom or dev board)
✅ Vape battery (3.7V LiPo, 300-900mAh)
✅ I2C sensor (BME280 or BME680)
✅ USB-C cable

💾 Software Requirements

✅ PlatformIO (recommended)
✅ Git
✅ ThingSpeak account (free)
✅ Arduino IDE (alternative)

Quick Start Guide

Step 1: Clone Repository

git clone https://github.com/Ans1S/esp32-c3-iot-sensor-board.git
cd esp32-c3-iot-sensor-board

Step 2: Configure Credentials

Each project includes a config.h.example template:

cd SW-VSCode/ESP32-Sensor/src
cp config.h.example config.h
# Edit config.h with your WiFi/ThingSpeak credentials

Step 3: ThingSpeak Setup

Create free account at thingspeak.com
Create new channel
Add fields:
- Field 1: Temperature (°C)
- Field 2: Humidity (%)
- Field 3: Pressure/IAQ
- Field 4: Battery (mV)
Copy Channel ID and Write API Key

Step 4: Get Receiver MAC Address

Flash this to your home station:

#include <WiFi.h>
void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  Serial.println(WiFi.macAddress());
}
void loop() {}

Step 5: Build & Upload

Using PlatformIO:

cd SW-VSCode/ESP32-Sensor
pio run --target upload
pio device monitor

Using Arduino IDE: Import the PlatformIO source from SW-VSCode/ into your preferred Arduino workflow if needed.

📁 Project Structure

esp32-c3-iot-sensor-board/
│
├── 📂 PCB/                       # Hardware Design Files (KiCad)
│   ├── Version 1/                # Initial design
│   ├── Version 2/                # Enhanced I2C + protection
│   └── Version 3/                # Optimized power path
│
├── 📂 SW-VSCode/                 # PlatformIO Projects
│   ├── ESP32-Sensor/             # BME280 sensor node
│   ├── ESP32-Extra-Sensor/       # BME680 air quality node
│   ├── ESP32-Home-Station/       # Central hub + WiFi gateway
│   ├── W-Charger-ThingSpeak-1A/  # Standalone WiFi (1A)
│   └── W-Charger-ThingSpeak-100mA/ # Standalone WiFi (100mA)
│
├── 📂 SW/                        # Arduino-style libraries and legacy sources
├── 📂 Datasheet/                 # Component Datasheets
├── 📂 Readme/                    # Documentation Images
│
├── 📄 .gitignore                 # Git ignore rules
├── 📄 LICENSE                    # MIT License
└── 📄 README.md                  # This file

📊 Performance Metrics

Sensor Node (Battery-Powered)

Metric	Value
⏱️ Active Time	~2-3 seconds per reading
😴 Sleep Time	1200 seconds (20 min, configurable)
🔋 Battery Life	3-12+ months (500mAh typical)
⚡ Deep Sleep Power	~10µA
📡 Active Power	~80mA (sensing)
📤 TX Power	~120mA (ESP-NOW)

Home Station (USB-Powered)

Metric	Value
📥 ESP-NOW Listening	~80mA
📶 WiFi Upload	~120mA (brief)
🔌 Power Source	USB 5V (always-on)
💾 Queue Capacity	20 readings

🔐 Security & Privacy

🔒 This repository does NOT contain sensitive credentials.

All WiFi passwords, API keys, and MAC addresses must be configured locally in config.h files, which are:

✅ Excluded via .gitignore
✅ Never committed to repository
✅ Documented via config.h.example templates

Before pushing to GitHub:

Verify config.h files are git-ignored
Only commit config.h.example templates
Never hardcode credentials in source files

🛠️ Troubleshooting

Check battery voltage (> 3.0V)
Verify I2C sensor connections (SDA/SCL)
Confirm receiver MAC address in config.h
Monitor serial output for error messages
Test sensor with I2C scanner

Ensure ESP-NOW on same WiFi channel
Verify MAC address matches sender config
Check distance between devices (< 100m)
Confirm station is powered and running
Review serial logs for ESP-NOW errors

Verify API key and Channel ID correct
Check WiFi connection status
Respect 15-second minimum upload interval
Monitor ThingSpeak rate limits
Check network firewall settings

Verify deep sleep is working (check serial)
Increase sleep interval in configuration
Check for sensor power leakage
Test battery capacity with multimeter
Ensure proper power path operation

🤝 Contributing

We welcome contributions from the community! Here's how you can help:

Ways to Contribute:

🐛 Report bugs via Issues
💡 Suggest new features
📝 Improve documentation
🔧 Submit pull requests
⭐ Star the project
📢 Share your builds

Development Areas:

📐 PCB design improvements
💻 Code optimization
🔋 Power management
🌡️ New sensor support
🐛 Bug fixes
🌐 Translations

Contribution Process:

Fork the repository
Create feature branch (git checkout -b feature/AmazingFeature)
Commit changes (git commit -m 'Add AmazingFeature')
Push to branch (git push origin feature/AmazingFeature)
Open Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

Third-Party Components:

🙏 Acknowledgments

Special thanks to:

Espressif Systems - ESP32-C3 platform and excellent documentation
Bosch Sensortec - High-quality BME280/BME680 environmental sensors
MathWorks - ThingSpeak IoT cloud platform
Open Source Community - Libraries, tools, and inspiration
Contributors - Everyone who has helped improve this project

📧 Contact & Links

⭐ Star this project if you find it useful!

♻️ Made with sustainability in mind for a greener future

Built with ❤️ using ESP32-C3 and recycled batteries

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publicMIT

esp32-c3-iot-sensor-board

@ans1s

28.35 × 28.7 mm · 1.6 mm · 2 layers