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Published2025-10-15
Understanding the Basics of Servo Motors and Arduino Uno
Arduino has become one of the most popular platforms for electronic projects, and connecting a servo motor to an Arduino Uno is one of the first steps many beginners take to explore the world of robotics and automation. In this part of the guide, we will delve into the basic concepts behind servo motors, how they work, and how to set up your Arduino Uno to control them effectively.
A servo motor is a small mechanical device used for precise control of angular position. Unlike regular DC motors, which can only spin continuously, a servo motor can rotate to a specific position and hold that position until told to move again. This makes it ideal for applications like robotic arms, steering systems in RC cars, and automated doors, where precise positioning is crucial.
Servo motors have three wires:
Power (usually 5V) – Supplies power to the motor.
Ground (GND) – Connects to the negative terminal of the power supply.
Signal – Receives the control signal (PWM) from the microcontroller, such as the Arduino, to tell the motor what position to move to.
Choosing the Right Servo Motor
There are different types of servo motors available, including standard and continuous rotation types. For most basic projects, a standard servo motor is enough. These can typically rotate from 0 to 180 degrees and hold any position in that range. Some popular examples are the SG90 and MG90S.
If you need your motor to rotate continuously (for instance, in a robot or a car), you would need to use a continuous rotation servo, which can spin indefinitely in either direction, but cannot stop at a specific angle.
For the purpose of this guide, we will use a standard servo that can rotate from 0 to 180 degrees.
Why Use Arduino Uno to Control a Servo?
The Arduino Uno is a fantastic microcontroller board for beginners. It’s affordable, easy to program, and has plenty of I/O pins to connect multiple components. With just a few lines of code, you can control a servo motor to move to a specified angle.
The Arduino Uno has built-in support for controlling servo motors through the Servo library, which makes this process incredibly simple. The library allows you to send a Pulse Width Modulation (PWM) signal to the servo motor, which is the standard method for controlling the position of servos.
Before you start, make sure you have the following items:
Servo motor (such as SG90 or MG90S)
Breadboard (optional, but helpful for organizing connections)
External power supply (optional, if your servo requires more power than the Arduino can provide)
Arduino IDE installed on your computer for programming
Wiring the Servo Motor to Arduino
Wiring the servo motor to your Arduino Uno is straightforward. Here’s how you do it:
Connect the Servo’s Power Pin: The red wire from the servo is the power supply. Connect it to the 5V pin on your Arduino.
Connect the Ground Pin: The black or brown wire is the ground. Connect it to the GND pin on your Arduino.
Connect the Signal Pin: The yellow or white wire from the servo is the signal wire. Connect this to a PWM-capable pin on your Arduino (usually pins 9, 10, or 11 work well).
Power the Arduino: If you’re using an external power supply for your servo, make sure the servo is powered independently from the Arduino. Use the Arduino’s Vin pin for this, or use a battery that matches the servo’s voltage requirements.
Once everything is connected, you’re ready to move on to the programming part of the project.
Programming the Arduino to Control the Servo Motor
Now that we’ve covered the basics of the servo motor and how to wire it to your Arduino, let’s move on to the fun part—programming the Arduino to control the motor’s movement. This section will walk you through writing your first simple program to move the servo to various positions.
Step 1: Install the Servo Library
Before you can control the servo, you need to include the Servo library in your Arduino sketch. This library is built-in and simplifies controlling the servo.
Go to Sketch > Include Library > Servo to add the Servo library to your sketch.
Here’s a simple example code to make your servo move back and forth:
#include // Include the Servo library
Servo myServo; // Create a servo object to control the servo
myServo.attach(9); // Pin 9 is connected to the signal pin of the servo
myServo.write(0); // Move servo to 0 degrees
delay(1000); // Wait for 1 second
myServo.write(90); // Move servo to 90 degrees (middle position)
delay(1000); // Wait for 1 second
myServo.write(180); // Move servo to 180 degrees
delay(1000); // Wait for 1 second
The line #include includes the Servo library, which provides all the necessary functions to control the servo.
The line Servo myServo; declares an object of type Servo called myServo. This will be used to control the servo motor.
In the setup() function, myServo.attach(9); attaches the servo to pin 9 on the Arduino (the pin where you connected the signal wire).
In the loop() function, myServo.write(angle); sends the desired angle (in degrees) to the servo. The servo moves to the specified angle, and the delay() function causes the program to pause for 1 second before moving to the next position.
Once your code is written, it’s time to upload it to your Arduino:
Make sure your Arduino Uno is connected to your computer via USB.
Click on the Upload button in the Arduino IDE. The code will be transferred to the Arduino board.
After uploading, the servo should begin moving back and forth between 0, 90, and 180 degrees.
Troubleshooting Common Issues
If your servo is not responding or behaving unexpectedly, here are a few things to check:
Power Supply: Make sure the servo is getting enough power. Some servo motors require more current than the Arduino can supply, especially if the motor is under load. In such cases, an external power supply for the servo may be needed.
Pin Connections: Double-check that the signal wire is connected to the correct PWM pin on the Arduino (pins 9, 10, or 11 typically).
Servo Specifications: Ensure that the servo motor you’re using is suitable for your project. Some servos may have different power and control requirements, so it’s always best to refer to the datasheet for specific details.
Additional Features and Enhancements
Once you have the basic servo control working, you can start experimenting with more complex projects. You could add a potentiometer to control the servo's position in real-time, or even build a simple robotic arm that can be controlled by your Arduino.
By now, you’ve learned how to connect a servo motor to your Arduino Uno, wire everything up correctly, and write a simple program to control the motor’s movements. In Part 2, we’ll explore more advanced techniques, including multiple servo control, using external power supplies, and incorporating sensors to create more dynamic projects. Stay tuned!
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Update：2025-10-15
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