💡 Level 1 – Fundamentals

Project 1.11: "Painting Robot"

🚀 Project 1.11 – Painting Robot

🎯 What You’ll Learn

✅ Goal 1: Move motors to draw straight lines.
✅ Goal 2: Combine turns to draw shapes (square, circle, triangle).
✅ Goal 3: Create free creative patterns.

Key Ideas

Digital output: Control motor direction.
PWM: Control motor speed.
Loops: Repeat movements to form shapes.
Timing: Control size of drawings.

🧱 Blocks Glossary (used in this project)

pinX = machine.Pin(X, machine.Pin.OUT) → Motor direction.
pwmX = machine.PWM(machine.Pin(X)) → Motor speed control.
pwmX.freq(2000) → Set PWM frequency.
pwmX.duty(value) → Set duty cycle (0–1023).
time.sleep() → Delay for movement duration.
for i in range(...) → Loop for repeated shapes.

🧰 What You Need

Part	How many?	Pin connection
D1 R32	1	USB cable
L298N Driver	1	IN1=Pin 2, IN2=Pin 4, ENA=Pin 5; IN3=Pin 12, IN4=Pin 13, ENB=Pin 14
Motors	2	Connected to L298N outputs
Structure	1	Holds pen/marker

✅ Before You Start

USB cable connected
Motors wired correctly
Pen attached to robot
Test print shows:

print("Ready!")  # Confirm serial is working

🎮 Microprojects (5 Mini Missions)

🎮 Microproject 1.11.1 – Draw a straight line

Blocks used: Digital output, PWM, Delay
Block sequence:

Setup motors forward
Run for 3s

MicroPython Code:

import machine, time                          # Import modules

pin2 = machine.Pin(2, machine.Pin.OUT)        # Motor A IN1
pin4 = machine.Pin(4, machine.Pin.OUT)        # Motor A IN2
pwm5 = machine.PWM(machine.Pin(5))            # Motor A ENA PWM

pin12 = machine.Pin(12, machine.Pin.OUT)      # Motor B IN3
pin13 = machine.Pin(13, machine.Pin.OUT)      # Motor B IN4
pwm14 = machine.PWM(machine.Pin(14))          # Motor B ENB PWM

pwm5.freq(2000)                               # Motor A frequency
pwm14.freq(2000)                              # Motor B frequency
pwm5.duty(512)                                # Motor A speed 50%
pwm14.duty(512)                               # Motor B speed 50%

pin2.value(1)                                 # Motor A forward
pin4.value(0)                                 # Motor A forward
pin12.value(1)                                # Motor B forward
pin13.value(0)                                # Motor B forward
print("Drawing straight line")                # Serial log

time.sleep(3)                                 # Run forward for 3 seconds

Reflection: Robot draws a straight line.
Challenge: Try longer time for longer line.

🎮 Microproject 1.11.2 – Square drawing

Blocks used: Digital output, PWM, Loop, Delay
Block sequence:

Forward 2s
Right turn 1s
Repeat 4 times

MicroPython Code:

import machine, time                          # Import modules

pin2 = machine.Pin(2, machine.Pin.OUT)        # Motor A IN1
pin4 = machine.Pin(4, machine.Pin.OUT)        # Motor A IN2
pwm5 = machine.PWM(machine.Pin(5))            # Motor A ENA PWM

pin12 = machine.Pin(12, machine.Pin.OUT)      # Motor B IN3
pin13 = machine.Pin(13, machine.Pin.OUT)      # Motor B IN4
pwm14 = machine.PWM(machine.Pin(14))          # Motor B ENB PWM

pwm5.freq(2000); pwm14.freq(2000)             # Set frequencies
pwm5.duty(512); pwm14.duty(512)               # Set speeds

for i in range(0, 4, 1):                      # Repeat 4 sides
    pin2.value(1); pin4.value(0)              # Motor A forward
    pin12.value(1); pin13.value(0)            # Motor B forward
    print("Forward side", i+1)                # Serial log
    time.sleep(2)                             # Forward 2s

    pwm5.duty(0)                              # Stop motor A
    pwm14.duty(512)                           # Motor B forward
    print("Right turn", i+1)                  # Serial log
    time.sleep(1)                             # Turn 1s

    pwm5.duty(512)                            # Restore motor A speed

Reflection: Robot draws a square.
Challenge: Try bigger square with longer forward time.

🎮 Microproject 1.11.3 – Draw a circle

Blocks used: Digital output, PWM, Delay
Block sequence:

Motor A faster
Motor B slower
Run for 5s

MicroPython Code:

import machine, time                          # Import modules

pin2 = machine.Pin(2, machine.Pin.OUT)        # Motor A IN1
pin4 = machine.Pin(4, machine.Pin.OUT)        # Motor A IN2
pwm5 = machine.PWM(machine.Pin(5))            # Motor A ENA PWM

pin12 = machine.Pin(12, machine.Pin.OUT)      # Motor B IN3
pin13 = machine.Pin(13, machine.Pin.OUT)      # Motor B IN4
pwm14 = machine.PWM(machine.Pin(14))          # Motor B ENB PWM

pwm5.freq(2000); pwm14.freq(2000)             # Frequencies
pwm5.duty(768)                                # Motor A faster
pwm14.duty(256)                               # Motor B slower

pin2.value(1); pin4.value(0)                  # Motor A forward
pin12.value(1); pin13.value(0)                # Motor B forward
print("Drawing circle")                       # Serial log

time.sleep(5)                                 # Run for 5 seconds

Reflection: Robot draws a circle.
Challenge: Try different speed ratios for bigger/smaller circles.

🎮 Microproject 1.11.4 – Triangle drawing

Blocks used: Digital output, PWM, Loop, Delay
Block sequence:

Forward 2s
Turn 120° (approx 2s)
Repeat 3 times

MicroPython Code:

import machine, time                          # Import modules

pin2 = machine.Pin(2, machine.Pin.OUT)        # Motor A IN1
pin4 = machine.Pin(4, machine.Pin.OUT)        # Motor A IN2
pwm5 = machine.PWM(machine.Pin(5))            # Motor A ENA PWM

pin12 = machine.Pin(12, machine.Pin.OUT)      # Motor B IN3
pin13 = machine.Pin(13, machine.Pin.OUT)      # Motor B IN4
pwm14 = machine.PWM(machine.Pin(14))          # Motor B ENB PWM

pwm5.freq(2000); pwm14.freq(2000)             # Frequencies
pwm5.duty(512); pwm14.duty(512)               # Speeds

for i in range(0, 3, 1):                      # Repeat 3 sides
    pin2.value(1); pin4.value(0)              # Motor A forward
    pin12.value(1); pin13.value(0)            # Motor B forward
    print("Forward side", i+1)                # Serial log
    time.sleep(2)                             # Forward 2s

    pwm5.duty(0)                              # Stop motor A
    pwm14.duty(512)                           # Motor B forward
    print("Turn 120 degrees", i+1)            # Serial log
    time.sleep(2)                             # Turn approx 120°
    pwm5.duty(512)                            # Restore motor A speed

Reflection: Robot draws a triangle.
Challenge: Try adjusting turn time for sharper angles.

🎮 Microproject 1.11.5 – Creative free pattern

Blocks used: Digital output, PWM, Delay
Block sequence:

Mix forward, backward, turns
Create unique path

MicroPython Code:

import machine, time                          # Import modules

# Motor A setup
pin2 = machine.Pin(2, machine.Pin.OUT)        # Motor A IN1
pin4 = machine.Pin(4, machine.Pin.OUT)        # Motor A IN2
pwm5 = machine.PWM(machine.Pin(5))            # Motor A ENA PWM

# Motor B setup
pin12 = machine.Pin(12, machine.Pin.OUT)      # Motor B IN3
pin13 = machine.Pin(13, machine.Pin.OUT)      # Motor B IN4
pwm14 = machine.PWM(machine.Pin(14))          # Motor B ENB PWM

# Configure PWM frequency
pwm5.freq(2000)                               # Motor A frequency
pwm14.freq(2000)                              # Motor B frequency

# Start with medium speed
pwm5.duty(512)                                # Motor A speed 50%
pwm14.duty(512)                               # Motor B speed 50%

# Forward movement
pin2.value(1); pin4.value(0)                  # Motor A forward
pin12.value(1); pin13.value(0)                # Motor B forward
print("Forward 2s")                           # Serial log
time.sleep(2)                                 # Forward 2s

# Backward movement
pin2.value(0); pin4.value(1)                  # Motor A backward
pin12.value(0); pin13.value(1)                # Motor B backward
print("Backward 2s")                          # Serial log
time.sleep(2)                                 # Backward 2s

# Left turn
pwm5.duty(0)                                  # Stop motor A
pwm14.duty(512)                               # Motor B forward
print("Left turn 1s")                         # Serial log
time.sleep(1)                                 # Turn left

# Right turn
pwm5.duty(512)                                # Motor A forward
pwm14.duty(0)                                 # Stop motor B
print("Right turn 1s")                        # Serial log
time.sleep(1)                                 # Turn right

# Stop motors
pwm5.duty(0)                                  # Stop motor A
pwm14.duty(0)                                 # Stop motor B
print("Pattern complete")                     # Serial log

Reflection: Robot creates a free pattern with mixed moves.
Challenge: Add more turns and speeds for creative paths.

✨ Main Project – Painting Robot

🔧 Blocks Steps (with glossary)

Digital output: Motor direction.
PWM: Motor speed.
Loops: Repeat shapes.
Timing: Control size of drawings.

Block sequence:

Setup motors.
Draw straight line.
Draw square.
Draw circle.
Draw triangle.
Create free pattern.

📖 External Explanation

This project shows how to choreograph robot movements to draw shapes.

Straight line teaches basic forward motion.
Square and triangle use loops and turns.
Circle uses speed differences.
Free pattern encourages creativity.

✨ Story Time

Imagine your robot as an artist 🎨. With each movement, it sketches lines, shapes, and curves. By combining speed and direction, your robot becomes a painter, creating unique patterns on the floor or paper.

🕵️ Debugging (2 Common Problems)

🐞 Debugging 1.11.A – Shapes distorted

Problem: Square sides uneven.
Clues: Forward time too short/long.
Broken code:

time.sleep(1)   # Forward too short

Fixed code:

time.sleep(2)   # Correct forward time

Why it works: Adjusting time ensures equal sides.

🐞 Debugging 1.11.B – Circle not smooth

Problem: Robot moves in jagged path.
Clues: Speed ratio not balanced.
Broken code:

pwm5.duty(1023)   # Too fast
pwm14.duty(100)   # Too slow

Fixed code:

pwm5.duty(768)    # Balanced speed
pwm14.duty(256)   # Balanced speed

Why it works: Balanced duty cycles create smooth circle.

✅ Final Checklist

Straight line works.
Square drawing works.
Circle drawing works.
Triangle drawing works.
Free pattern created.

📚 Extras

🧠 Student tip: Try combining shapes into a “robot signature.”
🧑‍🏫 Instructor tip: Show how timing changes shape size.
📖 Glossary: Duty cycle, forward, backward, turn.
💡 Mini tip: Always test one shape before combining patterns.