Session 6: Hand Coordinates & Quadrants
Session Architect: Muhammad Bilal
Duration: 50-60 minutes
Equipment Required:
- M3D Robotics Kit (robot with display attachment).
- Laptops with Scratch pre-installed.
- Scratch Hand Sensing Extension enabled.
- Whiteboard or chart to introduce the concept of coordinates.
- Paper and pencils for students to note coordinates.
Learning Objectives:
- Understand how Scratch can track the position of a hand/finger using x, y coordinates.
- Learn the concept of the Cartesian coordinate system (x,y axes).
- Apply hand position (input) to control the robot’s movement (output).
- Practice using conditionals and logical mapping in Scratch.
Resources:
Scratch Code for the session: AI Session 6.sb3 (20.1 KB)
1. Introduction to Coordinates (5 minutes)
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Instructions:
- Start by discussing directions. Ask students:
“If you want to tell a friend where to meet you, how do you describe the location?”
- Help students connect this to up/down and left/right (basic directions).
- Draw a simple grid on the board (like a map) with left-right and up-down axes.
- Introduce x (left ↔ right) and y (up
down) as coordinates that tell us the location of a point.
Teacher’s Role:
- Use real-life analogies to make the concept of coordinates simple.
- Explain positive vs negative values (e.g., positive x = right, negative x = left).
2. Understanding the Cartesian Coordinate System (5 minutes)
Activity 1: Drawing Coordinates (5 minutes)
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Instructions:
- Now, give blank graph sheets to students and guide students to draw their own coordinate grids on paper.
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Label the x and y axes, and then choose a point (e.g., 3,4) and mark it on the grid.
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Ask them:
“If the coordinates are 3, 4, where should I put the point on the grid?”
- Have students mark more points (like 4, -2, -3, -4) and show how to locate them.
Teacher’s Role:
- Walk around and help students with plotting the points on the grid.
- Ensure they understand that x tells you how far left/right, and y tells you how far up/down.
Activity 2: Coordinate Guessing Game
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Instructions:
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On the whiteboard, draw a large coordinate grid and mark points with coordinates.
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Ask students to guess the coordinates of a point. For example,
“Where is the point 3, 2? Can you find it on the grid?”
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This activity helps them reinforce the connection between coordinates and positions on the grid.
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Teacher’s Role:
- Engage students by having them actively guess and place points on the grid.
- Encourage students to explain their reasoning as they work out the answers.
3. Connecting Hand Movement to Coordinates (10 minutes)
Activity 1: Hand Tracking (5 minutes)
- Instructions:
Activity 1: Understanding Hand Position & Coordinates (5 minutes)
Instructions:
- Start by explaining that just like we use coordinates to locate points on a grid (like on a map), we can also use coordinates to track parts of our body.
- Example: “Imagine that we want to know where your hand is on a screen. We can track it using x and y coordinates, just like how we map points in math class.”
- Explain that x tells us how far left or right the hand is, and y tells us how far up or down it is.
Teacher’s Role:
- Draw a simple coordinate grid on the whiteboard again to reinforce the idea of left-right and up-down as x and y.
- Show how this concept applies to body parts like hands — instead of just points on a grid, we can track any part of our body (in this case, the hand) by finding its x and y position.
Activity 2: Tracking Your Hand in Scratch (5 minutes)
Instructions:
- Step 1:
- Open Scratch and load the provided session file (ensure that the camera turns on when the file is loaded).
- Step 2:
- Demo: Show how when we click the green flag, the Scratch sprite can track your thumb tip using your laptop camera. You’ll see real-time coordinates (x,y) change as you move your hand. The sprite will show the coordinates of your thumb tip as well as move to it.
- Step 3:
- Now, ask students to move their hand around the screen. Explain:
“As you move your hand up, down, left, or right, notice how the numbers change. The x-coordinate tells us how far your hand is left or right, and the y-coordinate tells us how far up or down your hand is.”
- Encourage them to test moving their hand across different areas (top-left, bottom-right, etc.), and observe the coordinates as well as see how well their hand is detected.
Ask them:
“What happens when your hand is at the top of the screen vs. the bottom? What about left vs. right?”
Teacher’s Role:
- Walk around and help students track their hand’s position using the x,y coordinates.
- Provide assistance for students who are having trouble tracking their hand using the camera.
Activity 2: Coordinate Practice (5 minutes)
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Instructions:
- In pairs, have students take turns moving their hands in front of the screen while their partner records the x,y values.
- Students should note the coordinates when the finger is placed in different sections of the screen (top-right, bottom-left, etc.).
- After a few rounds, discuss the patterns they see in the coordinates.
“What do you notice about the coordinates when your finger is in the top-left? How about the bottom-right?”
Teacher’s Role:
- Ensure students are recording accurate x,y values.
- Help them understand the correlation between movement and coordinates.
Got it! We can condense the observation + quadrant discovery into a single 5-minute hands-on exploration and then use the next 15 minutes for guided coding where students apply what they learned to make the robot react differently in each quadrant. Here’s the revised section:
4. Coding Robot Movement by Quadrants (20 minutes)
Part 1: Exploring Coordinates and Quadrants (5 minutes)
Instructions:
- Draw a large coordinate grid on the whiteboard with x and y axes, showing positive and negative values.
- Explain to students:
“The screen is like a big map, divided into different regions, just like city blocks. Today, we’ll explore four special sections called quadrants.”
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Activity:
- Have students move their hand/finger on the screen while observing the x and y coordinates in Scratch.
- Ask questions:
“What happens to x when you move right or left? What happens to y when you move up or down?”
- Let students experiment moving to different areas of the screen (top-right, top-left, bottom-left, bottom-right).
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Guided Discovery of Quadrants:
- Draw four sections on the whiteboard, then ask:
“Which section has both numbers positive? Which has one negative?”
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Guide them to identify each quadrant and note:
- Quadrant I: x+, y+ (Top-right)
- Quadrant II: x-, y+ (Top-left)
- Quadrant III: x-, y- (Bottom-left)
- Quadrant IV: x+, y- (Bottom-right)
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Encourage students to move their hand into each quadrant and call out the x,y values.
Teacher’s Role:
- Walk around, prompt students to observe patterns in coordinates.
- Help them connect coordinate signs to quadrant positions.
- Reinforce that these patterns will help teach the robot how to move.
Part 2: Coding Robot Actions for Quadrants (15 minutes)
Instructions:
- Open the Scratch file where the robot’s sprite will track hand position using the laptop camera.
- Explain:
“Now that we know the quadrants, we can teach the robot to respond differently depending on which quadrant our hand is in.”
“To code this, recall how we taught our robot to make different decisions based on changing conditions using the if-then and if-then-else blocks.”
“We are just going to combine these blocks with a condition that will check whether the hand is in a certain quadrant or not.”
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Guided Coding Activity:
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Step 1: Ask students to add if-then blocks to detect which quadrant the hand is in.
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Step 2: Decide a robot action for each quadrant, for example:
- Quadrant I → Move forward
- Quadrant II → Turn left
- Quadrant III → Move backward
- Quadrant IV → Turn right
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Step 3: Help students code these actions using Scratch blocks (motion, expressions, or sounds).
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Encourage them to experiment with different motions or robot expressions for each quadrant to make it fun and engaging.
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Testing & Iteration:
- Let students move their hand into each quadrant and observe the robot’s reaction.
- Ask reflective questions:
“Does the robot do what you expected? What can you change to make it better?”
- Encourage students to debug and refine their code in real time. Your final code should look like this:
Teacher’s Role:
- Guide students step-by-step in coding the if-then conditions.
- Encourage creativity: students can use motions, expressions, or sounds for each quadrant.
- Walk around to assist with debugging, reinforce the connection between coordinates, quadrants, and robot actions.
This way:
- Students discover quadrants themselves in 5 minutes.
- Then they spend 15 minutes applying that knowledge to program the robot in Scratch, making it hands-on and interactive.
- It keeps a smooth flow from observation → discovery → application.
If you want, I can also add mini checkpoints/mini-activities within the 15-minute coding part, so students interactively test each quadrant action one by one, making it more fun and manageable. Do you want me to do that?
5. Student Extensions & Creativity (10 minutes)
Activity 1: Adding Fun Actions (10 minutes)
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Instructions:
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Encourage students to customise the robot’s actions for each quadrant.
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They can add:
- Sounds (e.g., a beep when entering Quadrant II).
- Emojis (e.g., a sad face in Quadrant III).
- Speed variations (e.g., faster in Quadrant I).
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Suggest creative ways to combine movement, sounds, and visuals to make the project more interactive.
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Teacher’s Role:
- Guide students to creatively enhance their robot’s behavior.
- Help them test their ideas and make adjustments to ensure their code works.
6. Conclusion and Wrap-Up (5 minutes)
Activity:
Summarize the key concepts learned today and allow time for reflection.
Reflection Questions:
- “What happens when you move your finger up? Left? What happens to the robot?”
- “Why was it helpful to divide the screen into quadrants?”
- “What would you like to try next with the hand sensing system?”
Teacher’s Role:
- Lead the discussion and reinforce the concepts of coordinates and quadrants.
- Celebrate the creativity of students and encourage them to share their ideas for the next class.
Learning Outcome:
By the end of the session, students will:
- Understand how coordinates (x,y) control the robot’s movement.
- Be able to apply the concept of quadrants in real-life situations.
- Strengthen their coding skills by integrating conditionals and hand sensing into a creative project.
- Have a foundational understanding of how input (hand position) can control output (robot movement).