Creating Simple Autonomous Behavior

Combine motor control and sensors to give your robot autonomous movement and basic decision-making.

You’ve learned how to control your robot manually. Now it’s time to make it think for itself — at least a little! In this lesson, you’ll combine your motor and sensor skills to create simple autonomous behavior.

🤔 What Is Autonomous Behavior?

Autonomous robots make decisions based on sensor data instead of waiting for human input. This can be as simple as:

• Avoiding obstacles
• Following a line
• Choosing the clearest path

We’ll build a basic robot that explores its environment and avoids crashing into things.

🧠 Basic Decision-Making Logic

Here’s a simple behavior loop:

1. Move forward
2. Check for obstacle
   • If detected, stop
   • Scan left and right
   • Turn in the direction with more space
3. Repeat

🧪 Example: Obstacle-Avoiding Explorer

This example assumes:

• A forward-facing ultrasonic sensor
• Motors controlled with forward(), backward(), left(), right(), stop()
• Optional: sensor mounted on a servo for scanning

from time import sleep
from machine import Pin, time_pulse_us, PWM

# Set up motors and ultrasonic sensor
# (use previous lessons for wiring and functions)

def get_distance():
    # Trigger pulse and measure response
    trigger.low()
    sleep(0.002)
    trigger.high()
    sleep(0.01)
    trigger.low()
    duration = time_pulse_us(echo, 1, 30000)
    return duration / 58

def explore():
    while True:
        distance = get_distance()
        print("Distance:", distance)

        if distance > 20:
            forward()
        else:
            stop()
            backward()
            sleep(0.5)
            stop()
            right()
            sleep(0.5)
            stop()

        sleep(0.1)

# Run the loop
explore()

💡 Optional: Scan for Best Direction

If your sensor is on a servo, sweep left and right, then turn toward the direction with more space:

def scan_and_choose():
    set_angle(45)
    left_dist = get_distance()
    set_angle(135)
    right_dist = get_distance()
    set_angle(90)  # Reset forward

    if right_dist > left_dist:
        right()
    else:
        left()

🧩 Try It Yourself

• Add timed turns for corners
• Combine line following and obstacle avoidance
• Add randomness to movement direction for exploration

With autonomous behavior, your robot can now explore without constant input — a major milestone in robotics!

Next up: Final Project – Build Your Own Robot

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