ELIJAH'S AUTOMATED DICE ROLLER

Key Concepts

Servo Motion Principles

• Servo Angles: A servo motor moves to precise positions measured in degrees (0-180°)
• Torque: The Smart Servo can generate 13 Kg-cm of force, sufficient for moving lightweight objects
• Duty Cycle: How we control the position of the servo through pulse width modulation
• Servo Control: How the Circuit Python code sends commands to the servo

Programming Concepts

• Variables: Storing information like servo position or button state
• Conditional Statements: Making decisions based on input (if/else)
• Loops: Repeating actions continuously
• Timing: Controlling when and how long actions occur

Mechanical Design Principles

• Lever Systems: How to amplify motion through mechanical advantage
• Center of Gravity: How weight distribution affects dice rolling
• Material Selection: Choosing appropriate materials for different parts of the device

Activity: "Dice Roller Design Workshop"

1. Dice Physics Discussion:
   • Discuss with students the physics of dice rolling: randomization, tumbling, surfaces
   • Analyze what makes a "fair" roll vs. an unfair one
   • Consider how different dice (4-sided, 6-sided, 20-sided) behave differently
2. Programming Workshop:
   • Guide students in creating a custom program that:
     • Detects a button press
     • Activates the servo in a pattern that would effectively roll dice
     • Returns to a "ready" position for the next roll

import time
import board
from digitalio import DigitalInOut, Direction, Pull
import pwmio
import servo
import neopixel

# Setup button input
button = DigitalInOut(board.D2)
button.direction = Direction.INPUT
button.pull = Pull.UP

# Setup servo
pwm = pwmio.PWMOut(board.A2, duty_cycle=2 ** 15, frequency=50)
my_servo = servo.Servo(pwm)

# Setup NeoPixel for feedback
pixel = neopixel.NeoPixel(board.NEOPIXEL, 1)
pixel.brightness = 0.3

# Set initial position
my_servo.angle = 45  # Starting "ready" position
pixel.fill((0, 255, 0))  # Green means ready

# Main loop
while True:
    # Check for button press
    if button.value == 0:  # Button pressed
        pixel.fill((255, 0, 0))  # Red during roll
        
        # Dice rolling movement pattern
        my_servo.angle = 120  # Pull back
        time.sleep(0.3)
        my_servo.angle = 10   # Snap forward
        time.sleep(0.1)
        
        # Short delay before returning to ready position
        time.sleep(1)
        my_servo.angle = 45   # Return to ready
        pixel.fill((0, 255, 0))  # Green means ready
        
        # Debounce delay
        time.sleep(0.5)

3. Concept Sketching:
   • Have students create sketches of their dice roller designs
   • Encourage them to include:
     • Where the servo will be mounted
     • How the dice will be held and released
     • What type of container or surface will catch the dice
     • How the button will be positioned for Elijah's easy access

Extension Activity: "Design Optimization"

1. CAD Design Introduction:
   • Introduce students to OnShape CAD software
   • Demonstrate how to create simple 3D models for their dice roller components
   • Focus on designing:
     • A servo mount
     • A dice holding mechanism
     • A button holder optimized for Elijah's abilities
2. Prototype Construction:
   • Guide students in building functional prototypes using:
     • 3D printed parts they've designed
     • LocLine flexible connectors for adjustability
     • 10mm framing pieces for structure
   • Ensure designs consider:
     • Stability during operation
     • Accessibility of the button for Elijah
     • Containment of dice after rolling
     • Visibility of dice results
3. Code Refinement:
   • Challenge students to improve their code by adding:
     • Different rolling patterns for different types of dice
     • Visual feedback showing when the device is ready to roll
     • Customizable roll strength based on dice size

import time
import board
from digitalio import DigitalInOut, Direction, Pull
import pwmio
import servo
import neopixel

# Setup button input
button = DigitalInOut(board.D2)
button.direction = Direction.INPUT
button.pull = Pull.UP

# Setup toggle switch for dice selection
switch = DigitalInOut(board.D0)
switch.direction = Direction.INPUT
switch.pull = Pull.UP

# Setup servo
pwm = pwmio.PWMOut(board.A2, duty_cycle=2 ** 15, frequency=50)
my_servo = servo.Servo(pwm)

# Setup NeoPixel for feedback
pixel = neopixel.NeoPixel(board.NEOPIXEL, 1)
pixel.brightness = 0.3

# Set initial position
my_servo.angle = 45  # Starting "ready" position
pixel.fill((0, 255, 0))  # Green means ready

# Main loop
while True:
    # Check switch position for dice type
    if switch.value:  # Switch ON - small dice (d6)
        dice_type = "small"
        pixel.fill((0, 0, 255))  # Blue for small dice mode
    else:  # Switch OFF - large dice (d20)
        dice_type = "large"
        pixel.fill((255, 0, 255))  # Purple for large dice mode
    
    # Wait a moment to show the color
    time.sleep(0.5)
    pixel.fill((0, 255, 0))  # Back to green (ready)
    
    # Check for button press
    if button.value == 0:  # Button pressed
        pixel.fill((255, 0, 0))  # Red during roll
        
        # Different roll patterns based on dice type
        if dice_type == "small":
            # Gentle roll for small dice
            my_servo.angle = 100  # Pull back less
            time.sleep(0.2)
            my_servo.angle = 20   # Snap forward
            time.sleep(0.1)
        else:
            # Stronger roll for large dice
            my_servo.angle = 135  # Pull back more
            time.sleep(0.3)
            my_servo.angle = 5    # Snap forward more
            time.sleep(0.2)
        
        # Return to ready position
        time.sleep(1)
        my_servo.angle = 45
        pixel.fill((0, 255, 0))  # Green means ready
        
        # Debounce delay
        time.sleep(0.5)

Assessment Criteria

Students will demonstrate their understanding and application of the design process, programming concepts, and human-centered design principles through:

1. Prototype Demonstration: A working dice roller that meets Elijah's needs
2. Design Documentation: Technical drawings, code, and explanation of design choices
3. Reflection: Analysis of strengths, weaknesses, and future improvements
4. Presentation: Clear communication of the problem, process, and solution

Assessment Rubric

Final Reflection Activity

Guide students through a structured reflection using these prompts:

1. Design Process

• How did understanding Elijah's specific needs inform your design decisions?
• What was the most challenging part of the design process and how did you overcome it?
• How did your design change from initial concept to final prototype?

2. Technical Learning

• What did you learn about programming servo motors?
• How did the mechanical and digital aspects of your project work together?
• What would you do differently if you were to rebuild your project?

3. Empathy Development

• How has this project changed your understanding of the challenges faced by people with physical disabilities?
• How might your solution impact Elijah's gaming experience?
• What other assistive technologies could you design using the Smart Servo platform?

Extension Opportunities

For students who complete the project early or want additional challenges:

• Add multiple servo motors to create a more complex dice rolling mechanism
• Design a universal dice cup that can accommodate various dice shapes and sizes
• Create a companion app or interface that records dice roll results
• Design a modular system that could be adapted for other gaming accessories