Scratch Artificial Intelligence

Advanced

60 mins

Teacher/Student led

160 points

What you need:
Chromebook/Laptop/PC or iPad/Tablet
Webcam/camera

Scratch AI Pose Space Game

In this step-by-step lesson, you'll create a Space game using Scratch and Google Teachable Machine. You'll learn to control a spaceship using tilt poses, set up a new Scratch project, add a Rocketship sprite, load a Teachable Machine Model, display pose labels, set confidence thresholds, and make the spaceship move. You'll also learn to label poses, add a Star sprite, and make stars fall. Finally, you'll be challenged to improve your project.

Learning Goals Learning Outcomes Teacher Notes Lesson Files

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1 Introduction
2 Setup Scratch and TMPose2Scratch
3 Add the Rocketship Sprite
4 Load Teachable Machine Model
5 Display Pose Label
6 Set the Confidence Threshold
7 Move Left and Right
8 Label every x seconds
9 Add the Star sprite
10 Show and Make Stars Fall
11 Challenge
Challenge
Quiz

1 - Introduction

In this lesson, you will create a fun Space game using Scratch and Google Teachable Machine.

You will learn how to use your Teachable Machine Pose model with tilt poses to control a spaceship.

If you don't have a Teachable Machine Image model, don't worry! You can use the provided model.

5 points

2 - Setup Scratch and TMPose2Scratch

Go to https://stretch3.github.io/ and start a new Scratch project and delete the Cat sprite.

Then, add the TMPose2Scratch extension by clicking on the Extensions button at the bottom left corner of the screen and selecting TMPose2Scratch. This extension allows you to use Google Teachable Machine pose models in your Scratch projects.

When you add this extension, it will automatically try and use your computer's camera. If necessary, click on 'Allow' to give it permission to use your camera. You should see what the camera is showing in the stage area.

Scratch: How to add extension blocks

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

10 points

3 - Add the Rocketship Sprite

Add the Rocketship sprite to the project and then add the following code to it, to shrink it's size and position a the bottom center of the stage area.


when green flag clicked
  set size to (40) %
  go to x (0) y (-150)

Scratch: How to add a sprite from the library

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.

10 points

4 - Load Teachable Machine Model

Now, let's set up the pose model that our project will use. Add the following new code to your sprite:


 when green flag clicked
  set size to (40) %
  go to x (0) y (-150)
  pose classification model URL [link to your model] :: extension

Put the link of your pose model into the pose classification model URL block.

If you don't have your own pose model URL, you can use this one: https://teachablemachine.withgoogle.com/models/R9i0aRHth/

20 points

5 - Display Pose Label

Click on the 'pose label' block in the TMPose2Scratch extension category to turn it on. This will show you the current pose label being applied to what's being recorded on your webcam.

5 points

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Scratch is developed by the Lifelong Kindergarten Group at the MIT Media Lab. It is available for free at https://scratch.mit.edu