SG90 Servo Motor Dimensions: A Comprehensive Guide to Size, Specs, and Applications

The SG90 servo motor is a staple in the world of DIY electronics, robotics, and remote-controlled hobbies. Known for its affordability and reliability, this micro servo has become a favorite among makers and engineers. But what truly sets it apart is its compact design. In this first part of our guide, we’ll dissect the SG90’s dimensions, explore why its size matters, and uncover how its physical attributes influence performance in real-world projects.

Understanding the SG90’s Physical Dimensions

The SG90 is classified as a "micro" servo, a term that immediately hints at its small footprint. Let’s break down its exact measurements:

Length: 22.8 mm (0.9 inches) This front-to-back measurement includes the servo body and the output shaft. The streamlined length ensures it fits into tight spaces, such as robotic arms or drone flaps.

Width: 12.6 mm (0.5 inches) The width refers to the side-to-side size of the motor casing. This narrow profile allows multiple servos to be mounted side by side without overcrowding.

Height: 28.5 mm (1.1 inches) The height spans from the base of the servo to the top of the mounting ears. This dimension is critical for projects with vertical space constraints, like camera gimbals.

Weight: 9 grams (0.32 ounces) The lightweight design minimizes the overall load, making the SG90 ideal for aerial devices like drones, where every gram affects flight stability.

Mounting Hole Spacing: The SG90 features two mounting ears with holes spaced 24 mm apart. This standardized spacing aligns with common servo brackets and 3D-printed parts.

Shaft Dimensions: The output shaft extends 5 mm beyond the servo body and has a diameter of 4.8 mm. It supports standard servo horns, which are essential for connecting to wheels, arms, or other mechanisms.

Why Dimensions Matter in the SG90

The SG90’s compact size isn’t just about convenience—it directly impacts functionality. Here’s how:

Space Efficiency: In robotics, especially humanoid or insect-inspired bots, internal space is limited. The SG90’s micro design allows engineers to pack multiple servos into joints without compromising mobility. Power-to-Size Ratio: Despite its small stature, the SG90 delivers a torque of 1.8 kg·cm (4.8V), making it suitable for lightweight lifting and precise angular movements. Compatibility: Its dimensions adhere to micro servo standards, ensuring seamless integration with Arduino, Raspberry Pi, and other prototyping boards.

Technical Specifications Linked to Size

The SG90’s physical traits are closely tied to its performance metrics:

Operating Voltage: 3.5V–6V The low voltage requirement complements its small size, enabling use in battery-powered projects. Stall Current: 650 mA While compact, the motor draws significant current under load, necessitating a robust power supply in multi-servo setups. Rotation Angle: 180 degrees (90° in each direction) The limited rotation range suits applications requiring precise, repeatable movements rather than continuous rotation.

Design Challenges and Solutions

The SG90’s size does present challenges. For instance, its plastic gears, while lightweight, may wear out under heavy stress. However, users often mitigate this by:

Reinforcing gear teeth with lubricants. Using metal-gear upgrades for high-torque tasks. Pairing the servo with shock-absorbing mounts to reduce strain.

In the next section, we’ll dive into practical applications, design tips, and how the SG90 stacks up against larger servos.

In Part 1, we explored the SG90’s dimensions and their engineering implications. Now, let’s shift focus to its real-world applications, design best practices, and comparisons with other servo motors.

Applications Where Size Makes a Difference

The SG90’s compactness opens doors to innovative uses:

Robotics: Humanoid Robots: Fits into finger joints for lifelike hand movements. Hexapod Drones: Powers leg actuators without adding bulk. RC Models: Steering Systems: Small enough to fit inside 1:18 scale cars. Aileron Control: Used in model airplanes for smooth wing adjustments. Drones and UAVs: Camera Gimbals: Stabilizes lenses in tight spaces. Payload Releases: Deploys lightweight packages mid-flight. IoT and Smart Devices: Automated Planters: Adjusts sunlight exposure for indoor gardens. Security Cameras: Enables silent pan/tilt motion for surveillance.

Design Considerations for SG90 Integration

To maximize the SG90’s potential, consider these tips:

Space Planning: Use CAD software to model servo placement, ensuring clearance for wiring and movement. Heat Management: Avoid enclosing the servo in airtight spaces; its plastic casing lacks cooling vents. Wiring: Route cables away from moving parts to prevent snagging. The SG90’s 25 cm wire length offers flexibility.

SG90 vs. Larger Servos: A Size Comparison

How does the SG90 compare to bulkier models like the MG996R?

Feature SG90 MG996R Dimensions 22.8x12.6x28.5 mm 40.7x19.7x42.9 mm Weight 9 grams 55 grams Torque 1.8 kg·cm 11 kg·cm Best For Light-duty tasks Heavy lifting

While the MG996R excels in power, the SG90 wins in portability and energy efficiency.

Custom Modifications for Unique Projects

Hobbyists often tweak the SG90 to suit niche needs:

360-Degree Mod: Bypass the internal potentiometer to enable continuous rotation. 3D-Printed Mounts: Create custom brackets for unusual angles or surfaces. Waterproofing: Coat the servo in silicone for outdoor or underwater use.

Conclusion

The SG90 servo motor proves that big things come in small packages. Its dimensions make it a versatile tool for projects where space and weight are critical, while its performance holds up under moderate demands. Whether you’re building a mini robot or automating a smart home device, understanding the SG90’s size and specs ensures you harness its full potential.

By balancing compact design with functional reliability, the SG90 remains a go-to choice for innovators worldwide. Now, it’s your turn to put this tiny powerhouse to work!