Lidar Distance Microservice

Introduction

This document provides documentation for the Lidar Distance Controller, a Python-based program designed to handle Lidar data streaming, distance sending, and WebSocket communication. The program consists of three main threads: LidarDataThread, DistanceSenderThread, and WebSocketClientThread. Additionally, utility functions and global variables are imported from utils and globals modules, respectively.

Components

  1. Lidar Distance Main (LidarDistanceMain.py):
    • This module initializes and manages the main control logic of the robot.
    • It establishes connections, handles motor control, and manages various functionalities such as driving, spinning, and lightbar control.
  2. LidarDataThread (LidarDataThread.py):
    • Manages the Lidar data streaming from a specified IP and port.
    • Utilizes a Lidar data buffer to store and provide data to other threads.
  3. DistanceSenderThread (DistanceSenderThread.py):
    • Uses the Lidar data buffer for accessing Lidar data
    • Checks distances in five directions: left, front-left, front, front-right and right and sets the associated stopping flag if the distance is shorter than the minimum distance
    • Sends a stream of distance data for the five directions over a TCP connection to a specified IP and port.
  4. WebSocketClientThread (WebSocketClientThread.py):
    • Establishes a WebSocket client connection to a specified IP and port.
    • Sends a json package with the necessary information for stopping the robot to app control handler if one of the stop-flags, set by the DistanceSenderThread, is changing
  5. utils (utils.py):
    • Provides utility functions, including pregenerate_lidar_data for generating initial Lidar data, connect_to_server for connecting to a tcp server and signal_handler for handling Ctrl+C signals.
  6. globals (globals.py):
    • Contains global variables, including stop_threads to control thread termination and stop flags, e.g. stop_front, to stop the robot if to close to an obsticle.

Usage

Prerequisites

  • Python 3.x

Installation

  1. Clone the repository:

    git clone [repository_url]

Running the System

  1. Run the LidarDistanceMain script:

    python3 LidarDistanceController.py [lidarstream_ip] [lidarstream_port] [appHandler_ip] [appHandler_port] [distanceSender_ip] [distanceSender_port]

    Example:

    python3 LidarDistanceController.py 192.168.8.20 9011 192.168.8.20 6942 192.168.8.20 3031

    Replace the arguments with the appropriate values.

  2. To stop the program, use Ctrl+C. The program will gracefully terminate, stopping all threads.

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