Linux IoT Weatherstation

Embedded Linux system for the Raspberry Pi 3 Model B+ using Buildroot (https://buildroot.org/). Continuously reads temperature & humidity from an SHT31 sensor, logs data to SQLite, and serves a dashboard via a Python web app.

For the individual projects providing sensor readings and dashboard functionality, see prdktntwcklr/python-sht31 and prdktntwcklr/weatherman, respectively.

Features

• Automated sensor logging (SHT31 sensor via I2C)
• SQLite database storage
• Web dashboard for data visualization
• Cron job for periodic sampling
• Docker-based build environment
• Fallback mode for development/testing (random values)

Hardware Requirements

• Raspberry Pi 3 Model B+
• MicroSD card
• Sensirion SHT31 sensor (I2C)
• Jumper wires
• USB Micro-B cable
• RJ45 cable (optional)

Quick Start

1. Clone the repository

Important for Windows Users: Do not clone this repository into a standard Windows folder (e.g., C:\Users\...). Docker performance on Windows-mounted drives is extremely slow, and Buildroot will likely fail due to case-insensitivity and line-ending issues. Always clone and build inside the WSL2 internal filesystem.

git clone https://github.com/prdktntwcklr/weatherstation-linux.git
cd weatherstation-linux
git submodule update --init --recursive

2. Build with Docker Compose

docker compose run --rm --build build-app

3. Flash SD card

• Write output/images/sdcard.img build output to SD card
• Insert SD card into Raspberry Pi
• Power on and connect via serial
• Login: root / root

Project Structure

See buildroot-external/board/weatherstation/rootfs_overlay/ for overlays and scripts.

Data Logging (Cron Job)

Environmental data is sampled every 5 minutes via cron /var/spool/cron/crontabs/root:

*/5 * * * * /bin/python /root/log_data.py

Python Script Overview

The script /root/log_data.py:

• Opens SQLite database (/var/www/web-app/weather.db)
• Reads sensor values
• Inserts timestamped data
• Handles sensor errors with dummy values (-99.99)
• Simulates readings if no sensor is detected (for development)

Web Dashboard

The web server (Python, Gunicorn, Nginx) visualizes the collected data. Access via browser on the Pi's IP address.

Troubleshooting

• Dummy values (-99.99) indicate sensor read failure.
• Random values are used for development/testing.
• Ensure Docker is installed and running.
• Check logs in /var/www/web-app/ for web app issues.