How to Use servo motor : Examples, Pinouts, and Specs

A servo motor is a rotary actuator that allows for precise control of angular position, velocity, and acceleration. It consists of a motor coupled to a sensor for position feedback, along with a control circuit. Servo motors are widely used in applications requiring accurate movement and positioning, such as robotics, automation systems, RC vehicles, and industrial machinery. Their ability to maintain a specific position makes them ideal for tasks like steering mechanisms, robotic arms, and camera gimbals.

Servo motors come in various sizes and specifications, but the following are typical for standard hobby servo motors:

The servo motor typically has a 3-pin connector with the following pinout:

1. Power Supply: Connect the servo motor's VCC pin to a 5V or 6V power source, depending on the motor's specifications. Ensure the power supply can provide sufficient current (up to 1A for larger servos).
2. Ground Connection: Connect the GND pin to the ground of your circuit.
3. Control Signal: Connect the Signal pin to a PWM-capable pin on your microcontroller (e.g., Arduino).
4. PWM Signal: Generate a PWM signal with a pulse width between 1 ms and 2 ms to control the servo's position:
   • 1 ms corresponds to 0°.
   • 1.5 ms corresponds to 90° (center position).
   • 2 ms corresponds to 180°.

• Power Supply: Avoid powering the servo motor directly from the microcontroller's 5V pin, as it may not provide enough current. Use an external power source or a dedicated servo driver.
• Decoupling Capacitor: Place a capacitor (e.g., 100 µF) across the power supply lines to reduce voltage fluctuations caused by the servo's operation.
• Avoid Overloading: Do not exceed the servo's torque rating, as this can damage the motor or reduce its lifespan.
• PWM Frequency: Use a PWM frequency of 50 Hz (20 ms period) for standard servo motors.

Below is an example code to control a servo motor using an Arduino UNO:

#include <Servo.h> // Include the Servo library

Servo myServo; // Create a Servo object to control the motor

void setup() {
  myServo.attach(9); // Attach the servo to pin 9 on the Arduino
}

void loop() {
  myServo.write(0); // Move the servo to 0 degrees
  delay(1000);      // Wait for 1 second

  myServo.write(90); // Move the servo to 90 degrees
  delay(1000);       // Wait for 1 second

  myServo.write(180); // Move the servo to 180 degrees
  delay(1000);        // Wait for 1 second
}

• The Servo library simplifies the process of generating PWM signals for servo control.
• The myServo.write(angle) function sets the servo to a specific angle (0° to 180°).
• Ensure the servo is connected to a PWM-capable pin (e.g., pin 9 on the Arduino UNO).

1. Servo Motor Not Moving

   • Cause: Insufficient power supply.
   • Solution: Use an external power source capable of providing sufficient current.

2. Servo Jitters or Vibrations

   • Cause: Electrical noise or unstable power supply.
   • Solution: Add a decoupling capacitor across the power lines and ensure proper grounding.

3. Servo Overheating

   • Cause: Overloading or continuous operation at high torque.
   • Solution: Reduce the load on the servo or use a higher-torque model.

4. Servo Moves Erratically

   • Cause: Incorrect PWM signal or loose connections.
   • Solution: Verify the PWM signal timing and check all connections.

• Q: Can I rotate the servo motor beyond 180°?

  • A: Standard servo motors are limited to 180°. For continuous rotation, use a continuous rotation servo.

• Q: Can I control multiple servos with one Arduino?

  • A: Yes, you can control multiple servos using the Servo library, but ensure the power supply can handle the total current draw.

• Q: Why does my servo make a buzzing noise?

  • A: This is normal when the servo is holding its position under load. However, excessive noise may indicate overloading or a weak power supply.

By following this documentation, you can effectively integrate and troubleshoot a servo motor in your projects.