Scratch

Scratch is a programming language designed to teach children and teenagers the basics of coding in a fun and interactive way. It allows users to create games, stories and animations to develop their skills. Although targeted at kids, Scratch is a great way for anyone to take their first steps into coding, especially when combined with the Tello.

In the case of the Tello, you have two options of control; create a pre-planned mission with actions that you can start with the touch of a button or manually control the Tello with a device in real-time.

Step 1: Downloads

There are several different components required to use Scratch with your Tello. We will be using a Windows device; however, we will also note any differences if you’re using Apple.

1. First off, you need to start by downloading the Scratch Offline Editor from the Scratch website here.

Choose the correct version for the device you’re using.

If using a Mac, you will also have to download Adobe AIR as seen below:

1. Download Node. It is free and can be found here. Go with the version that is recommended for most users. Follow the instructions to download and install it.

2. Download the Tello files needed to run the code in Scratch. They are free and can be found here. They will show up as zipped files. You’ll need to extract or unzip them. You can do that by right-clicking.

Step 2: Node

You’ll have to open the Node program that you just downloaded. Once it is open you’ll need to find where you downloaded the Tello files. It is likely that they are in your downloads folder. Node is a command prompt program. My files were in my Downloads folder, in a Scratch folder. In fact when I extracted them it created another Scratch folder. In order to run the command needed here is how I did it.

Open Node.

Type cd downloads. Type cd scratch. That allowed me to access the correct location. Then type: node tello.js. You’ll see the program run and you are good to go. You may also have to authorise actions throughout this process. This process will be similar when using an Apple product but may differ with some steps.

Step 3: Scratch

Open Scratch. Hover your mouse over file and press Shift. At the bottom of the menu you’ll see Import Experimental HTTP Extension. Click on that. Then you’ll open your Tello.s2e file that you downloaded. It too is likely in your downloads folder.

Step 4: Connect the Tello

You’ll need to connect the Tello to your computer in order for them to communicate. Turn on the Tello and then find its WiFi network on your computer. Connect to it.

Using Scratch

Once you have everything installed and setup, you can begin using Scratch to control the Tello and create pre-planned flight.

In this section, we will be looking at the Tello controls used for flights and showing you four examples.

Scratch Controls

When using Scratch with your Tello, there are three main categories of blocks you will need to use, dependent on your type of flight.

Event – This is the block used as a trigger for something to happen. Flights are usually set to begin when the green flag is selected or space bar pressed.

More Blocks – This section is the specific controls put in for the Tello such as take off, fly forwards and flip.

Controls – This section allows you to add in instructions such as the duration of a move or repeat a move etc.

Sounds – We’ve added in this extra category for its entertainment value, you can input different sounds into your flight. Sounds are played on the device used to control the Tello, in our case, the Windows laptop.