How to Use Micro Servo : Examples, Pinouts, and Specs

The SG90 Micro Servo is a small, lightweight motor designed for precise angular movement. It is widely used in robotics, remote-controlled devices, and hobbyist projects due to its compact size, affordability, and ease of use. The servo can rotate to a specific angle within a range of 0° to 180°, making it ideal for applications requiring controlled motion, such as robotic arms, pan-tilt mechanisms, and model airplanes.

• Robotic arms and grippers
• Pan-tilt camera mounts
• Model airplanes and boats
• Automated mechanisms in hobbyist projects
• Educational electronics and prototyping

The SG90 Micro Servo is a 3-wire servo motor with a plastic gear system. Below are its key technical details:

The SG90 Micro Servo has three wires for connection. The pinout is as follows:

1. Power Supply: Connect the red wire to a 5V power source and the brown wire to ground (GND). Ensure the power supply can provide sufficient current (at least 500mA) to avoid voltage drops.
2. Signal Input: Connect the orange wire to a PWM-capable pin on your microcontroller (e.g., Arduino UNO pin 9 or 10).
3. PWM Signal: Use a PWM signal with a frequency of 50Hz (20ms period). The pulse width determines the servo angle:
   • 1ms pulse width: 0° position
   • 1.5ms pulse width: 90° position (center)
   • 2ms pulse width: 180° position

Below is an example Arduino sketch to control the SG90 Micro Servo:

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

Servo myServo; // Create a Servo object to control the SG90

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 (center position)
  delay(1000); // Wait for 1 second

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

• Avoid overloading the servo beyond its torque rating to prevent damage.
• Use an external power supply if multiple servos are used, as the Arduino's 5V pin may not provide sufficient current.
• Ensure the servo is not stalled (blocked from moving) for extended periods, as this can overheat the motor.

1. Servo Not Moving

   • Cause: Incorrect wiring or insufficient power supply.
   • Solution: Double-check the connections and ensure the power supply provides at least 4.8V and 500mA.

2. Servo Jitters or Vibrates

   • Cause: Electrical noise or unstable power supply.
   • Solution: Use a capacitor (e.g., 100µF) across the power supply to stabilize voltage.

3. Servo Moves Erratically

   • Cause: Incorrect PWM signal or interference.
   • Solution: Verify the PWM signal frequency (50Hz) and ensure proper grounding.

4. Servo Overheats

   • Cause: Prolonged stalling or excessive load.
   • Solution: Reduce the load on the servo and avoid blocking its movement.

Q: Can the SG90 rotate continuously?
A: No, the SG90 is a positional servo with a rotation range of 0° to 180°. For continuous rotation, use a continuous rotation servo.

Q: Can I power the SG90 directly from the Arduino?
A: While possible for a single servo, it is recommended to use an external power supply for reliable operation, especially when using multiple servos.

Q: How do I increase the servo's lifespan?
A: Avoid overloading, stalling, and operating the servo at high temperatures. Use it within its specified voltage and torque limits.

Q: Can I control the SG90 without a microcontroller?
A: Yes, you can use a servo tester or a 555 timer circuit to generate the required PWM signal.