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rtu_v5/.planning/research/STACK.md
2026-03-12 06:04:19 +08:00

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Stack Research

Domain: Web-based RTU Interface for Raspberry Pi Embedded Sensor Monitoring Researched: 2026-03-12 Confidence: HIGH

Core Technologies

Technology Version Purpose Why Recommended
Flask 3.1.0 Lightweight Python web framework The de facto standard for Raspberry Pi web projects. Extensive ecosystem, minimal overhead, perfect for Pi Zero 2 W. Multiple verified projects use Flask for sensor dashboards.
Flask-SocketIO 5.6.0 Real-time bidirectional communication Proven combination with Flask for live sensor data. Latest version (5.6.0) released Dec 2025, compatible with Python 3.8+.
Chart.js 4.4.x JavaScript charting library Industry standard for dashboard visualizations. Lightweight (~60KB), canvas-based rendering performs well on embedded displays. Extensive documentation and examples for Raspberry Pi projects.
Bootstrap 5.3.x CSS framework for responsive UI Works exceptionally well for touchscreen interfaces. Built-in support for 1024x600 resolution layouts. Grid system simplifies the menu-driven RTU interface.
Python 3.11+ Backend runtime Raspberry Pi OS (Bookworm) ships with Python 3.11. Excellent sensor library ecosystem (GPIO, I2C, serial).

Supporting Libraries

Library Version Purpose When to Use
python-socketio 5.12.0+ Socket.IO client/server Required by Flask-SocketIO, handles WebSocket transport
psutil 6.1.0+ System monitoring Reading CPU temp, memory for health checks
pyserial 3.5+ Serial communication Reading sensor data from ADC/serial ports
smbus2 0.5+ I2C communication Water level sensors, other I2C devices
gunicorn 23.0+ WSGI server Production deployment, replaces Flask dev server
eventlet 0.40+ Async worker Recommended for Flask-SocketIO production (better than gevent)
paramiko 3.5+ SSH/SFTP SCP/SFTP file transmission to server

Real-Time Communication

Technology Purpose Why Use
Socket.IO (via Flask-SocketIO) Server-push for sensor updates Bidirectional, auto-reconnection, fallback to polling. Proven in multiple Pi monitoring projects.

Development Tools

Tool Purpose Notes
systemd Service management Auto-start Flask app on boot, restart on failure
Chromium Kiosk Mode Local display chromium-browser --kiosk --incognito http://localhost:8080
nginx Reverse proxy Route 8080 (kiosk) and 9090 (remote) ports

Installation

# Core Python packages
pip install flask==3.1.0
pip install flask-socketio==5.6.0
pip install python-socketio==5.12.0

# Sensor and system access
pip install psutil==6.1.0
pip install pyserial==3.5
pip install smbus2==0.5

# Production server
pip install gunicorn==23.0
pip install eventlet==0.40

# File transmission
pip install paramiko==3.5

# Frontend (via CDN or download)
# - Bootstrap 5.3.x CSS/JS
# - Chart.js 4.4.x
# - Socket.IO client 4.x

Alternatives Considered

Recommended Alternative When to Use Alternative
Flask FastAPI Only if you need async/await for high-concurrency (50+ concurrent users). Flask is simpler for embedded.
Flask Quart If you prefer async Flask syntax. Flask-SocketIO still works but adds complexity.
Socket.IO Server-Sent Events (SSE) SSE is simpler (no JS library) but only one-way. Use only if you never need client→server real-time messages.
Socket.IO Polling Only for absolute minimal overhead. Not recommended—Socket.IO overhead is negligible, benefits are substantial.
Chart.js Lightweight Charts Only if you need financial-style candlestick charts. Chart.js is better for standard line/bar charts.
Bootstrap 5 Pure CSS If you need absolute minimum footprint. Bootstrap adds ~200KB but saves大量 development time for touchscreen layouts.

What NOT to Use

Avoid Why Use Instead
Django Too heavy (~30MB+), complex setup, overkill for embedded RTU Flask (lightweight, sufficient for this use case)
FastAPI While fast, adds Pydantic complexity without benefit. Async not needed for single-user dashboard Flask (simpler, same performance for this use case)
React/Vue/Angular Framework overhead, build step required, memory intensive on Pi Zero Vanilla JS + Bootstrap (direct, no build, ~500KB total)
Node.js Adds runtime complexity, unnecessary for Python-centric sensor stack Python/Flask (native sensor access, simpler deployment)
gunicorn (threading mode) Doesn't work well with Flask-SocketIO eventlet worker (required for WebSocket support)
InfluxDB + Grafana Full database + visualization stack, too heavy for Pi Zero Flask + Chart.js (direct data, minimal overhead)

Stack Patterns by Variant

If running on Pi Zero 2 W (primary target):

  • Use Flask development server (python app.py) for simplicity
  • Single worker, Socket.IO handles concurrency
  • Minimal CSS, avoid heavy JavaScript frameworks
  • Reason: Pi Zero 2 W has limited RAM (~512MB), every MB counts

If running on Pi 3B (alternative):

  • Can use gunicorn + eventlet with 2-4 workers
  • More aggressive caching allowed
  • Consider nginx for static files
  • Reason: Pi 3B has more RAM (~1GB), can handle more overhead

If remote HD interface needed (port 9090):

  • Serve same Flask app on different port
  • Use CSS media queries to show full HD layout on larger screens
  • No separate codebase needed
  • Reason: Single app, responsive design handles both

Version Compatibility

Package Compatible With Notes
Flask 3.1.0 Python 3.10+ Requires Python 3.10 minimum
Flask-SocketIO 5.6.0 Flask >=2.1.0, python-socketio >=5.12.0 Use latest python-socketio for best performance
Socket.IO client 4.x Flask-SocketIO 5.x Client/server version must match protocol
Bootstrap 5.3.x All modern browsers No IE11 support (not needed for kiosk)
Chart.js 4.4.x All modern browsers Requires canvas support
eventlet 0.40+ Python 3.10+ Monkey-patching required before other imports
psutil 6.1.0 Python 3.8+ Works on all Pi models

Why This Stack

Performance on Pi Zero 2 W

  • Flask overhead: ~10-15MB RAM (vs Django ~80MB)
  • Chart.js canvas rendering is GPU-accelerated on Pi
  • Socket.IO connection: ~1-2MB per client
  • Total app footprint: ~50-80MB RAM

Developer Experience

  • Flask: Simple, Pythonic, extensive documentation
  • Bootstrap: Ready-made touchscreen-friendly components
  • Chart.js: Extensive examples for real-time data
  • Single codebase serves both kiosk (1024x600) and remote (HD)

Ecosystem Evidence

Multiple verified GitHub projects use this exact stack:

  • g1forfun/Pi-Monitor — Flask + Socket.IO + Chart.js (Pi 5 dashboard)
  • Mohammed-Shehsin/sensehat-iot-dashboard — Flask + real-time sensors
  • idleCyrex/raspberry-pi-weather-station — Flask + environmental monitoring
  • Multiple Raspberry Pi community tutorials (Cytron, official forums)

Sources

  • Flask-SocketIO PyPI — Verified latest version 5.6.0 (Dec 2025), Python 3.8+ compatibility
  • piwheels.org — Verified Flask-SocketIO 5.6.0 available for Raspberry Pi OS
  • GitHub g1forfun/Pi-Monitor — Active project (last push Feb 2026), Flask + Socket.IO + Chart.js pattern
  • GitHub sensehat-iot-dashboard — Real-time sensor example with Flask
  • Cytron.io tutorial — "Create a Real-Time Raspberry Pi Dashboard" (Dec 2025), Flask + Chart.js + psutil
  • Multiple Raspberry Pi forum discussions — Confirmed Flask + Socket.IO is the community standard for sensor dashboards

Stack research for: Raspberry Pi RTU Web Interface Researched: 2026-03-12