LocalEdge Env Monitor

📅 GOAL
Build a reliable, modular, testable IoT system that reads from DHT22 and ENS160 sensors on a Pico W (MicroPython) and delivers environmental data to a Flask API running on a Raspberry Pi 5. Data is then served to a Dashboard UI.

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🔹 Features

• Read temperature & humidity (DHT22)
• Monitor eCO2 and TVOC levels (ENS160)
• Local threshold evaluation on device
• Real-time dashboard served from Pi
• JSON-based communication over HTTP
• SQLite storage and file logger
• AWS MQTT support for remote sync
• Modular, test-driven design

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🩵 Supported Sensors

✨ DHT22

• Measures: Temperature (°C), Humidity (%)
• Range: -40 to +80 °C / 0-100% RH
• Resolution: 0.1 °C / 0.1% RH
• Protocol: Single-wire digital

✨ ENS160

• Measures: Air Quality Index (AQI), eCO2, TVOC
• Interface: I2C
• Useful for: Indoor air pollution detection

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📚 Key Libraries

MicroPython (on Pico W)

• machine, time, ujson, urequests
• Custom ENS160 MicroPython driver

Python (on Pi5)

• flask, sqlite3, logging, requests, pytest, paho-mqtt
• Adafruit_DHT (if fallback sensor code on Pi is needed)

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🎨 Architecture Diagram

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🧱 Project Structure

localedge-env-monitor/
├── app/
│   ├── aws/
│   │   ├── __init__.py
│   │   └── mqtt_client.py        # Publishes to AWS IoT Core
│   ├── pi/
│   │   ├── __init__.py
│   │   └── pi5.py                # Entry point for Flask API on Pi5
│   ├── sensors/
│   │   ├── __init__.py
│   │   ├── dht22.py              # Threshold-aware DHT22 logic
│   │   ├── ens160.py             # Threshold-aware ENS160 logic
│   │   └── sensor_manager.py     # Routes data to storage, logger, cloud
│   ├── storage/
│   │   ├── __init__.py
│   │   └── sqlite_db.py          # SQLite persistence layer
│   ├── app_logging/                     # Centralized app_logging output
│   ├── routes.py                 # Flask endpoints
│   └── __init__.py               # App factory init
├── static/                       # Dashboard static assets
├── templates/
│   └── index.html                # Dashboard frontend
├── test/
│   ├── __init__.py
│   ├── test_dht22.py             # Unit test for DHT22 sensor logic
│   ├── test_ens160.py            # Unit test for ENS160 sensor logic
│   ├── test_sensor_manager.py    # Sensor manager logic test
│   ├── test_flask_api.py         # Flask endpoint + payload format
│   ├── test_logger.py            # Logger formatting / output
│   ├── test_db_storage.py        # SQLite write + read verification
│   └── test_pipeline.py          # E2E integration test
├── README.md                     # You’re here
├── requirements.txt              # Dependencies
├── run.py                        # Main entry for app
├── sandbox.py                    # Dev/test utils
└── .env                          # Secret keys + config (not committed)

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🌐 System Overview

• Pico W (MicroPython):

  • Runs sensor code for DHT22 + ENS160
  • Each sensor checks thresholds and returns status
  • Sends data as JSON to Pi via POST /data

• Raspberry Pi 5 (Flask API):

  • Receives data from Pico W
  • Sensor Manager stores in SQLite and logs events
  • Dashboard UI fetches real-time values from the API

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🧪 Testing Strategy

Component	Test File	Description
DHT22 Sensor	test/test_dht22.py	Unit test for temperature & humidity readings
ENS160 Sensor	test/test_ens160.py	Unit test for AQI, TVOC, and CO₂ thresholds
Sensor Manager	test/test_sensor_manager.py	Validates routing, AWS, and local logging
Flask API	test/test_flask_api.py	Tests /data POST and dashboard GET routes
Logger System	test/test_logger.py	Verifies log entries, format, and rotation
SQLite Storage	test/test_db_storage.py	CRUD tests on sensor DB storage layer
End-to-End Pipeline	test/test_pipeline.py	Simulates PicoW → API → SQLite → Dashboard

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🚀 Getting Started

1. Prepare Pico W

• Flash with MicroPython firmware
• Use mpremote to upload MicroPython sensor code

2. Set Up Pi5

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
python run.py

3. Connect Sensors

• Connect DHT22 + ENS160 to Pico W GPIO
• Run MicroPython code to send data

4. Visit Dashboard

• Access Flask server via browser (e.g. http://raspberrypi.local:5000)

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📦 Tech Stack

• 🐍 Python 3.12
• 🌐 Flask
• 🪪 PyTest
• 🛠 SQLite
• 🌬 DHT22, ENS160
• 📶 MicroPython + Pico W