How to Use Servo SG90: Examples, Pinouts, and Specs

The Servo SG90 is a small, lightweight servo motor widely used in hobby projects, robotics, and remote-controlled devices. It is designed to provide precise control of angular position, making it ideal for applications such as steering mechanisms, robotic arms, and pan-tilt camera systems. Its compact size, affordability, and ease of use make it a popular choice for beginners and experienced makers alike.

• Model: SG90
• Type: Analog Servo Motor
• Operating Voltage: 4.8V to 6.0V
• Operating Speed: 0.1 seconds/60° at 4.8V, 0.09 seconds/60° at 6.0V
• Torque: 1.8 kg·cm at 4.8V, 2.2 kg·cm at 6.0V
• Weight: 9 grams
• Angle Range: 0° to 180°
• Control Signal: Pulse Width Modulation (PWM)
• Connector Type: 3-pin female header (compatible with standard servo connectors)

The Servo SG90 has a 3-pin connector with the following pinout:

1. Power Connection: 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 Connection: Connect the orange wire to a PWM-capable pin on your microcontroller (e.g., Arduino).
3. PWM Signal: Send a PWM signal to the servo to control its position. The pulse width determines the angle:
   • 1ms pulse width corresponds to 0°.
   • 1.5ms pulse width corresponds to 90° (center position).
   • 2ms pulse width corresponds to 180°.

• Power Supply: Avoid powering the servo directly from the microcontroller's 5V pin, as it may not provide enough current. Use an external power source if possible.
• PWM Frequency: The SG90 typically operates at a PWM frequency of 50Hz (20ms period).
• Avoid Overloading: Do not exceed the torque rating to prevent damage to the servo.
• Mechanical Stops: The servo has built-in mechanical stops to limit its range to 180°. Forcing it beyond this range can damage the gears.

Below is an example of how to control the Servo SG90 using an Arduino UNO:

#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
}

Code Explanation:

• The Servo library simplifies controlling the SG90.
• The attach() function links the servo to a specific PWM pin.
• The write() function sets the servo's position in degrees (0° to 180°).

1. Servo Not Moving:

   • Cause: Insufficient power supply.
   • Solution: Use a dedicated power source capable of providing at least 500mA.

2. Servo Jittering:

   • Cause: Electrical noise or unstable power supply.
   • Solution: Add a decoupling capacitor (e.g., 100µF) across the power supply.

3. Servo Overheating:

   • Cause: Prolonged operation under high torque or incorrect PWM signal.
   • Solution: Ensure the servo is not overloaded and verify the PWM signal is within the correct range.

4. Limited Range of Motion:

   • Cause: Incorrect PWM signal or mechanical obstruction.
   • Solution: Check the PWM signal and ensure there are no physical obstructions.

Q: Can I use the Servo SG90 with a 3.3V microcontroller?
A: Yes, but you must power the servo with 4.8V-6.0V and use a level shifter for the PWM signal if necessary.

Q: How many SG90 servos can I control with an Arduino?
A: The number depends on the available PWM pins and the power supply's capacity. Ensure the power supply can handle the total current draw.

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

Q: What is the lifespan of the SG90?
A: The lifespan depends on usage conditions, but it is generally durable for hobby projects when operated within its specifications.