You can already train a pose model. Today you will load that model into Scratch and build a space game you steer by leaning left and right.
You will start a new project in Stretch3 and build the game step by step, testing and fixing it as you go.
Before you touch any code: how would leaning your body to one side make a rocket move across the screen?
Your pose-controlled space game has five parts:
- Load your model into Scratch.
- Read the pose it sees, and set how confident it must be before you act on it.
- Move the rocket left and right from that pose.
- Check the pose regularly rather than once.
- Add stars that fall for you to dodge or catch.
If the rocket jitters or ignores you, it is almost always the confidence threshold or how often you are checking.
Set up a new project in Stretch3 with the TMPose2Scratch extension:
- Go to https://stretch3.github.io/ and start a new project.
- Delete the Cat sprite.
- Click the Extensions button at the bottom left of the screen and choose TMPose2Scratch (not Posenet2Scratch or TM2Scratch). This extension lets you use Google Teachable Machine pose models in Scratch.
- The extension tries to use your computer's camera straight away. If your browser asks, click Allow. You should now see what the camera shows on the stage.
Understanding and Adding Extensions in Scratch
What are Scratch Extensions?
Scratch Extensions are additional sets of blocks that expand the capabilities of your Scratch projects. They allow you to:
- Mention extensions like Pen here
- Connect with external hardware (e.g., microbits)
- Access web-based services (e.g., Google Translate, Amazon Text to Speech)
- Use more advanced programming features
How Extensions Work
When you add an extension to your project:
- New blocks appear in the blocks palette
- These blocks are grouped under a category named after the extension
- You can use these blocks just like any other Scratch blocks
Adding an Extension to Your Project
- Look for the "Add Extension" button in the bottom-left corner of the Scratch editor
- Click the "Add Extension" button
- A window will open showing all available extensions
- Browse through the options or use the search bar to find a specific extension
- Click on the extension you want to add
- The extension is now added to your project, and its blocks appear in the blocks palette
Add the Rocketship sprite to the project and then add the following code to it, to position it at the bottom centre of the stage area and shrink its size.
when green flag clicked
go to x (0) y (-150)
set size to (30) %
To add a sprite from the sprite library follow these steps:
- Put your mouse over the Choose a Sprite button
- Click on the magnifying glass
- Find the sprite you want in the library
- Click on your chosen sprite
You can use search box or the filter links (Animals, People, Fantasy etc) to locate your sprite.
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This lesson is copyright of Coding Ireland 2017 - 2026. Unauthorised use, copying or distribution is not allowed.
Scratch is developed by the Lifelong Kindergarten Group at the MIT Media Lab. It is available for free at https://scratch.mit.edu