JavaScript Robotics: Building Autonomous Drones with JavaScript

In recent years, the field of robotics has seen tremendous growth and innovation. With the advent of JavaScript, a versatile and widely used programming language, developers now have the power to build autonomous robots and drones using familiar tools and frameworks. In this article, we will explore the exciting world of JavaScript robotics by focusing on building autonomous drones.

JavaScript Robotics and Drones

Traditionally, building robots and drones required knowledge of specialized languages such as C++ or Python. However, JavaScript has emerged as a viable alternative due to its ease of use, wide adoption, and a vibrant ecosystem of libraries and frameworks.

JavaScript robotics involves integrating hardware components, such as sensors and actuators, with JavaScript code to control and interact with the robot. Drones, in particular, offer an excellent platform for JavaScript robotics as they require complex control algorithms and real-time responsiveness, which JavaScript can handle effectively.

Getting Started: Setting up the Environment

Before diving into drone programming, let's set up the development environment. We'll be using Node.js, a popular JavaScript runtime, along with some libraries and frameworks specifically designed for robotics.

• Install Node.js − Visit the official Node.js website and download the latest stable version for your operating system.

• Create a New Project − Open a terminal and create a new directory for your project. Navigate to the project directory using the cd command.

• Initialise a Node.js Project − Run the following command in the terminal to initialise a new Node.js project:

npm init -y

Install Dependencies − Install the necessary dependencies for robotics and drones:

npm install johnny-five node-ardrone

Building the Autonomous Drone

In this section, we will create a simple autonomous drone that can take off, fly in a specified pattern, and land. We will be using the Johnny-Five library, a popular JavaScript robotics framework, along with the node-ardrone package for drone-specific functionality.

Import the Required Libraries − Create a new JavaScript file, autonomous-drone.js, and import the necessary libraries:

const five = require('johnny-five');
const arDrone = require('node-ardrone');

Explanation

In the first few lines, we import the necessary libraries for our autonomous drone project. The johnny-five library provides a high-level API for interacting with hardware components, and the node-ardrone package allows us to control the AR.Drone.

Connect to the Drone − Initialise the drone and establish a connection −

const drone = arDrone.createClient();

Explanation

Next, we create a new drone client object using the createClient() method provided by the node-ardrone package. This object represents our AR.Drone and allows us to send commands to control its movements.

Configure the Drone − Set up the drone's configuration, such as enabling stabilisation and enabling video streaming:

drone.config('general:navdata_demo', 'FALSE');
drone.ftrim();
drone.disableEmergency();
drone.on('navdata', (data) => {
   // Handle navigation data updates
});

Explanation

Here, we configure the drone by disabling the navigation data demo mode, performing a flat trim to stabilise the drone, and disabling the emergency mode. We also set up a listener for the 'navdata' event, which provides us with real-time navigation data from the drone. You can add custom code inside the event handler to process and utilise this data.

Take Off − Command the drone to take off:

drone.takeoff();

Explanation

The takeoff() method is used to command the drone to take off from the ground. Once executed, the drone will start its engines and hover at a fixed altitude.

Fly in a Pattern − Implement a function to make the drone fly in a square pattern:

function flyInSquare() {
   drone
   .after(5000, function () {
      this.clockwise(0.5);
   })
   .after(2000, function () {
      this.stop();
      this.land();
   });
}

Explanation

The flyInSquare() function defines a flight pattern for the drone. It uses the Johnny-Five library's after() method to schedule specific actions at certain time intervals. In this case, after 5 seconds, the drone will start rotating clockwise at a speed of 0.5 (ranging from -1 to 1). After another 2 seconds, it will stop rotating and command the drone to land.

Execute the Flight − Call the flyInSquare function to start the drone's autonomous flight:

flyInSquare();

Explanation

Here, we simply call the flyInSquare() function to initiate the drone's autonomous flight in a square pattern.

Landing − Implement a listener to detect when the drone lands:

drone.on('landing', () => {
   console.log('Drone landed!');
});

Explanation

We set up a listener for the 'landing' event, which is triggered when the drone successfully lands. When the event is detected, the callback function is executed, and the message "Drone landed!" is printed to the console.

To see the output, you can run the script in the terminal using the following command −

node autonomous-drone.js

The expected output will be −

Drone landed!

Please note that in order to execute this code successfully, you need to have an AR.Drone or a compatible drone available and connected to your computer. Additionally, make sure you have the required dependencies installed and that your drone is properly configured.

Conclusion

JavaScript has opened up exciting possibilities in the field of robotics, enabling developers to build autonomous drones using familiar tools and frameworks. In this article, we explored the basics of JavaScript robotics and demonstrated how to build an autonomous drone using JavaScript, the Johnny-Five library, and the node-ardrone package. With further exploration and experimentation, you can extend the functionality of your drone and create even more advanced autonomous behaviors.