MG90S 9g Micro Metal Gear Servo Motor Instruction Manual

1. Introduction and Overview

The Beffkkip MG90S 9g Micro Metal Gear Servo Motor is a compact and durable actuator designed for a wide range of electronic and robotic applications. This servo is an updated version of the SG90, featuring metal gears for enhanced longevity and performance. It is an ideal choice for hobbyists and professionals working on projects such as RC cars, planes, helicopters, fixed-wing aircraft, gliders, small robots, robotic arms, and Arduino-based systems.

Figure 1.1: Beffkkip MG90S 9g Micro Metal Gear Servo Motors (4-pack).

Its small size, combined with robust metal gearing and a coreless motor, provides a good balance of power and precision for various control surface movements and articulation needs.

Figure 1.2: Wide range of applications for the MG90S servo motor.

2. Product Features

The MG90S servo motor is engineered with several key features to ensure reliable and efficient performance:

• Metal Gear Construction: Equipped with aluminum metal gears, providing superior durability, reduced noise, and smoother operation compared to plastic or copper gears.
• Coreless Motor: Offers high efficiency and quick response times.
• Double Ball Bearings: Enhances stability, reduces friction, and extends the service life of the servo.
• High-Quality Silicone Cables: Designed for high temperature resistance and a longer service life.
• Compact and Lightweight: With a weight of approximately 15g, it is suitable for projects where space and weight are critical.
• Standard Connector: Features a JR/FUTABA universal plug type for broad compatibility with various receivers and microcontrollers.

Figure 2.1: Internal structure and components of the MG90S servo.

Figure 2.2: Gear material comparison, emphasizing aluminum metal gears.

3. Specifications

Below are the detailed technical specifications for the MG90S servo motor:

Figure 3.1: MG90S Servo Parameters.

4. Setup and Installation

Proper setup is crucial for the optimal performance and longevity of your MG90S servo motor.

4.1 Wiring Connections

The MG90S servo motor comes with a standard 3-wire connector. Ensure correct polarity when connecting to your power source and control board:

• Red Wire: Positive pole (VCC)
• Brown Wire: Negative pole (GND)
• Yellow Wire: Signal (PWM input)

4.2 Power Supply

The MG90S operates within a voltage range of 4.8V to 6V. It is critical to provide a stable power supply within this range. Using an inadequate or excessively high voltage can lead to erratic behavior, overheating, or permanent damage to the servo.

Note: When using with microcontrollers like Arduino, ensure your power supply can deliver sufficient current (e.g., 2A or more) at the appropriate voltage (e.g., 5V or 7.5V if using a separate regulated supply for the servos) to prevent brownouts or erratic servo movement, especially when multiple servos are in use or under load.

4.3 Mounting

The servo motor includes mounting tabs with pre-drilled holes for easy installation. Use appropriate screws (typically included) to secure the servo to your desired location. Ensure the servo is mounted firmly to prevent vibrations or movement during operation.

Various servo horns (arms) are provided to attach to the output shaft, allowing you to connect linkages for controlling movement. Select the appropriate horn based on your application's requirements.

Figure 4.1: Product dimensions and included accessories.

5. Operating Instructions

Servo motors like the MG90S are controlled by sending a Pulse Width Modulation (PWM) signal. The width of this pulse determines the angular position of the servo shaft.

5.1 Control Signal

The MG90S typically operates with a pulse width ranging from 500µsec to 2500µsec, corresponding to its full 180° range of motion. A pulse width of approximately 1500µsec usually corresponds to the center position (90°).

• Minimum Pulse (e.g., 500µsec): Rotates the servo to one extreme (e.g., 0°).
• Center Pulse (e.g., 1500µsec): Rotates the servo to the center position (e.g., 90°).
• Maximum Pulse (e.g., 2500µsec): Rotates the servo to the other extreme (e.g., 180°).

The servo's operating speed indicates how quickly it can move to a commanded position. For the MG90S, this is 0.11 seconds per 60 degrees at 4.8V and 0.09 seconds per 60 degrees at 6V.

Figure 5.1: Servo 180-degree rotation range.

5.2 Programming with Microcontrollers

When using microcontrollers like Arduino, you can utilize the built-in Servo library to easily control the MG90S. This library simplifies the generation of the necessary PWM signals.

Example (Arduino):

#include <Servo.h>

Servo myServo;
int servoPin = 9;

void setup() {
  myServo.attach(servoPin);
}

void loop() {
  myServo.write(0);   // Move to 0 degrees
  delay(1000);
  myServo.write(90);  // Move to 90 degrees
  delay(1000);
  myServo.write(180); // Move to 180 degrees
  delay(1000);
}

Ensure your code accounts for the servo's maximum angle and operating speed to avoid over-stressing the motor or causing jitter.

6. Maintenance

The MG90S servo motor is designed for durability, but proper maintenance can further extend its lifespan and ensure consistent performance:

• Keep Clean: Regularly inspect the servo for dust, dirt, or debris, especially around the output shaft and mounting points. Clean with a soft, dry cloth.
• Avoid Overloading: Do not exceed the specified stall torque. Continuous stalling or excessive force can damage the internal gears and motor.
• Check Connections: Periodically verify that all wiring connections are secure and free from corrosion or damage. Loose connections can lead to intermittent operation.
• Lubrication: The metal gears are pre-lubricated. Avoid applying additional lubricants unless specifically recommended by the manufacturer, as improper lubricants can attract dust or degrade plastic components.
• Environmental Conditions: Operate the servo within its specified temperature range (0-55 °C). Avoid exposure to extreme temperatures or moisture, as the servo is not waterproof.

7. Troubleshooting

If you encounter issues with your MG90S servo motor, consider the following troubleshooting steps:

7.1 Servo Not Responding or Erratic Movement

• Power Supply: Verify that the power supply voltage is within the 4.8V-6V range and can provide sufficient current. An underpowered servo may exhibit jitter, weak torque, or fail to move.
• Wiring: Double-check all wiring connections for correct polarity (Red to VCC, Brown to GND, Yellow to Signal) and ensure they are firmly seated.
• Control Signal: Confirm that your microcontroller or RC receiver is sending a valid PWM signal within the 500-2500µsec range. Test with a known working signal source if possible.
• Mechanical Obstruction: Ensure there are no physical obstructions preventing the servo horn from moving freely.

7.2 Jittery or Unstable Movement

• Power Fluctuations: This is often caused by an unstable or insufficient power supply. Try adding a capacitor across the servo's power lines or using a dedicated power supply for the servos.
• Signal Noise: Electrical noise can interfere with the PWM signal. Keep signal wires away from high-current wires or motors.
• Dead-band Setting: While the MG90S has a fixed dead-band, excessive mechanical play in the gears can sometimes mimic jitter.

7.3 Servo Locked Up or Not Moving at All

• Physical Damage: Inspect the gears for any visible damage or foreign objects. A locked-up gear often indicates internal mechanical failure.
• Overload: If the servo was subjected to excessive force or continuous stalling, the motor or gears might be damaged.
• Defective Unit: In rare cases, a servo might be defective from manufacturing. If all other troubleshooting steps fail, consider replacing the unit.

8. Warranty and Support

The Beffkkip MG90S servo motor typically comes with a return policy allowing for refund or replacement within 30 days of purchase, subject to the retailer's terms and conditions.

For technical support, warranty claims, or inquiries regarding defective units, please contact the seller or manufacturer directly through your purchase platform. Provide your order details and a clear description of the issue to facilitate a quick resolution.