Rainbow HAT with Raspberry Pi on BalenaOS

This repository contains a Go application for reading sensor data from the Rainbow HAT on a Raspberry Pi running BalenaOS. The application reads temperature, humidity, and pressure data, and publishes it via MQTT while also serving a simple web page to display the current sensor data.

Table of Contents

• Requirements
• Installation
• Configuration
• Running the Application
• Accessing the Web Server via Balena Public URL
• Endpoints
• Shutdown
• License

Requirements

• Raspberry Pi with BalenaOS
• Rainbow HAT
• Go 1.18+
• MQTT broker
• .env file with necessary configurations
• Docker

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/rainbowhat-sensor-reader.git
   cd rainbowhat-sensor-reader

2. Ensure you have Go installed:

   Follow the instructions on the official Go website to install Go.

3. Install dependencies:

   This project uses a go.mod file to manage dependencies. Ensure you are in the project directory and run:

   go mod tidy

4. Create a .env file:

   touch .env

   Populate the .env file with the following variables:

   ID=RBH01
   MQTT_HOST=tls://[xyz......tyu].s1.eu.hivemq.cloud
   MQTT_PORT=8883
   MQTT_USER=test
   MQTT_PASS=test
   MQTT_CLIENT_ID=test
   MQTT_TOPIC=rainbowhat/weather
   PORT=:80
   REFRESH_INTERVAL=60

Configuration

• ID: A unique ID for your sensor.
• MQTT_HOST: The host URL of your MQTT broker.
• MQTT_PORT: The port number for your MQTT broker.
• MQTT_USER: The username for your MQTT broker.
• MQTT_PASS: The password for your MQTT broker.
• MQTT_CLIENT_ID: Your MQTT client ID (can be left empty if not needed).
• MQTT_TOPIC: The MQTT topic to publish sensor data to.
• PORT: The port on which the web server will run (e.g., :80).
• REFRESH_INTERVAL: The interval (in seconds) at which sensor data is read and published.

Running the Application

Using Balena to Run on Raspberry Pi

1. Install Balena CLI:

   Follow the instructions on the official Balena CLI documentation to install the Balena CLI.

2. Log in to Balena:

   balena login

3. Initialize the project:

   balena push <your-app-name>

   Replace <your-app-name> with the name of your Balena application. This command will build and deploy the application to your Raspberry Pi. You need to have a Balena application set up with a Raspberry Pi device before running this command to deploy the application.

Running Locally

1. Build and run the application using Docker:

   Make sure Docker is installed and running on your machine. Then, from the project directory, run:

   docker build -t rainbow-hat-sensor-service .
   docker run --env-file .env -p 8080:8080 rainbow-hat-sensor-service

Accessing the Web Server via Balena Public URL

1. Enable Public URL:

   Go to the Balena dashboard, select your application, and enable the Public Device URL for your device. This will provide you with a URL through which you can access your web server.

2. Configure Environment Variables:

   Set the PORT environment variable to 80 in your Balena application configuration. This ensures that the web server listens on the correct port for the Balena public URL.

   PORT=:80

3. Access the Web Server:

   Once the application is running, you can access the web server using the public URL provided by Balena.

Endpoints

• Root Endpoint (/): Serves an HTML page displaying the current sensor data.
• Data Endpoint (/data): Serves the current sensor data in JSON format.

Shutdown

The application is designed to handle graceful shutdown upon receiving an interrupt signal (e.g., Ctrl+C or a termination signal).

License

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