Learn Python From Scratch: Build a Self-Moving Robot

Hey everyone! I’m Xiao P, a Python enthusiast who loves robotics. Today, let’s work on an interesting project – making a robot move by itself using Python! Sounds cool, right? Join me on this magical coding journey!

Robot Development Tools

When it comes to robot development, we must mention our main characters – the Python library rospy from the Robot Operating System (ROS), and the RPi.GPIO library for control. These two libraries are simply the “golden duo” in the robotics world! rospy allows us to easily control various parts of the robot, while RPi.GPIO handles the low-level hardware control. They are not only easy to use but also support various sensors and actuators, enabling our robot to see and move.

Setting Up the Development Environment

Before we start, we need to prepare our tools. You will need:

# Install Python 3.7 or higher
# Install ROS and rospy on Ubuntu
sudo apt-get install ros-noetic-desktop-full
sudo apt-get install python3-rospy

# Install GPIO library on Raspberry Pi
pip install RPi.GPIO
pip install numpy scipy

Tip: If you are using a Raspberry Pi, it’s recommended to update your system first:

sudo apt-get update
sudo apt-get upgrade

Making the Robot Move

Let’s start with basic motor control. First, let’s write a simple motor driver program:

import RPi.GPIO as GPIO
import time

class MotorController:
    def __init__(self, left_forward, left_backward, right_forward, right_backward):
        # Set GPIO mode
        GPIO.setmode(GPIO.BCM)
        # Initialize motor pins
        self.pins = [left_forward, left_backward, right_forward, right_backward]
        for pin in self.pins:
            GPIO.setup(pin, GPIO.OUT)
    
    def move_forward(self, duration=1):
        # Control the motor to move forward
        GPIO.output(self.pins[0], GPIO.HIGH)
        GPIO.output(self.pins[2], GPIO.HIGH)
        time.sleep(duration)
        self.stop()

    def stop(self):
        # Stop all motors
        for pin in self.pins:
            GPIO.output(pin, GPIO.LOW)

# Create an instance of the motor controller
robot = MotorController(17, 18, 22, 23)

This code accomplishes the basic functions of moving forward and stopping. Isn’t it simple? Next, we can get the robot running!

Smart Navigation Upgrade

Now let’s add some advanced features! Let’s give the robot an obstacle avoidance function:

import RPi.GPIO as GPIO
import time

class SmartRobot:
    def __init__(self):
        self.motor_controller = MotorController(17, 18, 22, 23)
        # Set ultrasonic sensor pins
        self.TRIG = 24
        self.ECHO = 25
        GPIO.setup(self.TRIG, GPIO.OUT)
        GPIO.setup(self.ECHO, GPIO.IN)
    
    def get_distance(self):
        # Send ultrasonic signal
        GPIO.output(self.TRIG, True)
        time.sleep(0.00001)
        GPIO.output(self.TRIG, False)

        # Wait for echo
        while GPIO.input(self.ECHO) == 0:
            start_time = time.time()
        while GPIO.input(self.ECHO) == 1:
            end_time = time.time()

        # Calculate distance
        duration = end_time - start_time
        distance = duration * 17150
        return distance

    def smart_navigation(self):
        while True:
            distance = self.get_distance()
            if distance > 20:  # If the obstacle is more than 20 cm away
                self.motor_controller.move_forward()
            else:
                self.motor_controller.stop()
                time.sleep(1)

This upgraded version adds ultrasonic obstacle avoidance, allowing the robot to automatically detect obstacles in front and react accordingly. You can also add more sensors to make the robot smarter!

The Future is Bright

Through this Python robot project, I believe everyone has gained a new understanding of programming and robotics. This is just the beginning; in the future, you can add even cooler features like computer vision and voice recognition. Python makes robot development so easy and fun; let’s continue exploring more possibilities together!

Don’t forget to follow me, and next time we’ll play with something even more interesting!