MagnumPi

A simple web application to manage Raspberry PI GPIO.

Actually this is a work in progress, any suggestions will be appreciated!

Screenshots

Available features

The following feature are already available

• /gpio: allows to send high or low signal to a GPIO pin
• /lcd: allows to to send a text to a I2C LCD display
• /led_blink: allows to blink a led connected to a specific GPIO PIN
• /tasks: allows to create background tasks. Actually this is only a demo page, that shows how to create and handle background tasks
• /camera: show a live video streaming from a PiCamera (or a simulated one if not available)

Requirements

This project requires:

• Python 3.6
• Redis

Redis installation depends on your platform:

• macOS, you can install with Brew brew install redis
• Linux, you can install via terminal sudo apt-get install redis-server

When Redis is installed, simply start it with this command:

$ redis-server

Usage and deployment

To start this web application, follow the following steps.

• Clone the repository:

git clone git@github.com:BubiDevs/MagnumPi.git
cd MagnumPi

• Create the virtual environment and install the dependencies:

python3 -m venv venv
source venv/bin/activate
(venv) pip install -r requirements.txt

Note: if you are installing the webapp on RaspberryPi, use the requirements-rpi.txt file. It will install the platform dependant packages to use GPIO and LCD display.

python3 -m venv venv
source venv/bin/activate
(venv) pip install -r requirements-rpi.txt

Development

As pre-requisited, clone and install the dependencies as descibed in the Usage and deployment section.

During the development phase, you can run the web application using flask. These are the commands that you need to run the app:

source venv/bin/activate
(venv) cd code
(venv) export SIMULATOR=1
(venv) export FLASK_APP=magnumpi.py
(venv) rq worker magnumpi-tasks
(venv) flask run --host=0.0.0.0

Some notes:

• SIMULATOR is a bash variable that allows the application to run outside a Raspberry Pi. Access to GPIO is simulated through mock classes inside fakeRPi package. Use SIMULATOR=1 when the wep application is not running on a Raspberry PI.
• --host=0.0.0.0 allows to access flask web site also from outside the local machine
• Redis must be running on the same machine in order to start the application (it's possible to change this configuration inside config.py file)
• rq worker magnumpi-tasks this command start a worker for Redis. You can also start more workers depending on your needs.

Deployment

As pre-requisited, clone and install the dependencies as descibed in the Usage and deployment section.

For the production deploy, we are going to use gunicorn as production web server. Install it using pip:

(venv) pip install gunicorn

In a separate terminal tab, start redis workers:

cd MagnumPi
source venv/bin/activate
(venv) cd code
(venv) rq worker magnumpi-tasks

To start MagnumPi under gunicorn:

(venv) cd code
(venv) gunicorn -b localhost:8000 -w 4 magnumpi:app

Note: If you need to access to web application from outside the deployment machine, you'll need to change localhost with the IP of the target machine.

ToDo

Here is a list of the planning activities. Some are quite simple, other could be a little bit tricky to implement.

• GPIO section: set to low or high a specific pin
• GPIO section: read a value from a specific pin
• GPIO section: support for GPIO buttons
• Add the capability to stop a background task (running or queued)
• Display the current status of a running job directly in the task table
• Handle errors if LCD display is not connected
• Support multiline strings in LCD display
• Review and improve MyGPIO class

References

• The Flask Mega-Tutorial
• Flask Video Streaming Revisited
• How to setup an I2C LCD on the Raspberry Pi
• Raspberry Pi Pinout