# Technology Stack

**Analysis Date:** 2026-03-12

## Project Status

This is a **greenfield project** - no implementation code exists yet. The repository currently contains only:
- `THE_IDEA.md` - Requirements specification document
- `.opencode/` - OpenCode/GSD framework configuration

The following stack analysis is based on the requirements defined in `THE_IDEA.md`.

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## Languages

**Primary:**
- **HTML/CSS/JavaScript** - Web-based UI for the 7-inch touchscreen and remote full HD interface
  - Expected to run in Chromium Kiosk Mode on Raspberry Pi
  - Must support dual resolution: 1024x600 (touchscreen) and 1920x1080 (remote)

**Secondary:**
- **Python** (likely) - Backend for sensor data collection, CSV processing, and network operations
  - Raspberry Pi standard runtime
  - Used for serial communication with sensors (ADC, rainfall sensors)
  - CSV file generation and management

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## Runtime

**Environment:**
- **Raspberry Pi OS** - Primary runtime on Pi Zero 2 W and Pi 3B
  - Pi Zero 2 W: ARMv8 single-core, 512MB RAM
  - Pi 3B: ARMv7 quad-core, 1GB RAM

**Browser:**
- **Chromium** - Kiosk mode for touchscreen interface
  - Target URL: `http://pihostname:8080` (touchscreen)
  - Target URL: `http://pihostname:9090/` (remote full HD)

**Package Manager:**
- Not yet established (pending project initialization)

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## Frameworks

**Core:**
- **Lightweight web framework** (TBD) - For serving the UI
  - Options: Flask, FastAPI (Python), or simple HTTP server
  - Must be performant on low-power Pi Zero 2 W
- **Frontend** - Plain HTML/CSS or lightweight framework
  - Recommendation: Static HTML/CSS for main interface (performance)
  - Avoid heavy SPA frameworks to minimize memory footprint

**Sensor Interfaces:**
- **Serial communication** - For ADC, rainfall sensors, GPS
- **SDI-12** - For soil moisture and evapotranspiration sensors (referenced in requirements)

**Data Handling:**
- **CSV processing** - For data logging and transfer (per flowchart in THE_IDEA.md)

**Build/Dev:**
- Not yet established (pending project initialization)

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## Key Dependencies

**Hardware Interfaces:**
- Serial port communication (Python pyserial or similar)
- ADC reading libraries
- GPS module support (USB)

**Network:**
- FTP client (for data transfer to myvscada server)
- SCP/SFTP client
- WebDAV client
- TCP socket libraries

**Data Processing:**
- CSV generation and parsing libraries
- Data validation utilities

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## Configuration

**Network Settings:**
- Local IP configuration (static IP)
- Subnet mask, gateway, DNS
- MAC address
- Transfer protocol selection (FTP/SCP/SFTP/WEBDAV)

**Sensor Configuration:**
- ADC channels (4-20mA, 0-10vDC types)
- Rainfall sensor settings
- Water level thresholds
- Evapotranspiration settings

**Server Settings:**
- Server IP and TCP port
- Tide data hours
- GPS coordinates (manual or USB GPS)

**Mobile Settings:**
- Phone numbers for alerts (Master, SubMaster, Engineer contacts)

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## Platform Requirements

**Development:**
- Standard web development tools (editor, browser)
- Python development environment
- Git for version control

**Production:**
- Raspberry Pi Zero 2 W or 3B
- 7-inch capacitive touchscreen (1024x600)
- Chromium browser (Kiosk mode)
- Network connectivity (Ethernet or mobile/GPRS)

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## Performance Constraints

| Resource | Target | Concern |
|----------|--------|---------|
| RAM | <256MB for UI | Pi Zero 2 W has only 512MB total |
| Startup time | <3 seconds | Cold start in Chromium Kiosk |
| Bundle size | Minimal | Optimize for low-power device |

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*Stack analysis: 2026-03-12*