Traffic Light SDK Usage Guide
=============================

This chapter will detail how to use the `tl.py` module in `Traffic Light SDK` to control traffic lights on a Raspberry Pi.

Running Environment
-------------------
The `Traffic Light SDK` is designed to run on a Raspberry Pi with the following specifications:

- **Operating System:** Raspbian (or any other compatible Raspberry Pi OS)
- **Python Version:** Python 3.7 or higher
- **Hardware Requirements:**
  - Raspberry Pi board (tested on Raspberry Pi 4)
  - GPIO pins connected to traffic light hardware

Ensure your Raspberry Pi is properly set up with an operating system and Python environment before proceeding.

Install Dependencies
--------------------
Ensure you have installed the necessary Python libraries. You can install them via pip:

.. code-block:: bash

   pip install RPi.GPIO

Initialization and Configuration
--------------------------------
First, import the `TrafficLight` class and create an instance:

.. code-block:: python

   from tl import TrafficLight

   traffic_light = TrafficLight()

This will set up GPIO pins but will not initialize them immediately. You need to manually call the `setup_gpio()` method to complete the initialization:

.. code-block:: python

   if traffic_light.setup_gpio():
       print("GPIO setup completed.")
   else:
       print("Failed to setup GPIO.")

Usage Example with Command Line Interface (CLI)
-----------------------------------------------
The `demo.py` script demonstrates how to control traffic lights using the `tl.py` module via a command line interface (CLI). Below is a detailed explanation of the script and how to use it.

Script Overview
^^^^^^^^^^^^^^^

The `demo.py` script provides several command-line options to control the traffic lights. It uses the `argparse` module to parse command-line arguments and calls corresponding methods on the `TrafficLight` object.

Available Commands:

- **Turn on red light:**

  .. code-block:: bash

     python demo.py --red_on

- **Turn off red light:**

  .. code-block:: bash

     python demo.py --red_off

- **Turn on green light:**

  .. code-block:: bash

     python demo.py --green_on

- **Turn off green light:**

  .. code-block:: bash

     python demo.py --green_off

- **Turn on both red and green lights:**

  .. code-block:: bash

     python demo.py --all_on

- **Turn off both red and green lights:**

  .. code-block:: bash

     python demo.py --all_off

- **Turn on red light only:**

  .. code-block:: bash

     python demo.py --red_on_only

- **Turn on green light only:**

  .. code-block:: bash

     python demo.py --green_on_only

Running the Script
^^^^^^^^^^^^^^^^^^

To run the script, simply execute it from the command line with the desired option. For example, to turn on the red light:

.. code-block:: bash

   python demo.py --red_on

If no command-line arguments are provided, the script will print help information:

.. code-block:: bash

   python demo.py

This will display all available options and their descriptions.

Contents
--------

.. toctree::

   api