Top Servo Motors for ESP32 Projects - SG90, MG90S and More

Quick Links #

If you're looking for code examples, you can find Arduino IDE, ESP-IDF, ESPHome, PlatformIO, Micropython examples here:

• SG90 Code Examples
• MG90S Code Examples
• MG996R Code Examples
• PCA9685 Code Examples.

Servo Motors enables precise control of movement in applications like robotic arms, camera gimbals, and smart devices. Choosing the right servo motor for an ESP32-based project depends on key factors such as torque, size, power requirements, and compatibility with the ESP32's PWM capabilities.

When integrating servo motors with an ESP32, it’s important to consider specific factors to ensure compatibility and optimal performance:

• Torque: Determines the motor's ability to handle loads and resist external forces.
• Size: The physical dimensions of the servo motor dictate its suitability for compact or space-constrained projects.
• Power Requirements: Voltage and current demands vary between servo models

Most Popular Servo Motors #

Servo motors are widely used with the ESP32 due to their compatibility with PWM signals and their ability to perform precise angular motion. Below is an overview of some of the most popular servo motors used in ESP32 projects, highlighting their key specifications, common use cases, and reasons for their popularity.

SG90 #

The SG90 is one of the most widely used micro servo motors, known for its small size, low cost, and versatility. Weighing just 9 grams, it is perfect for lightweight projects. Despite its compact build, the SG90 offers a torque of approximately 1.8 kg/cm, sufficient for handling small loads like a camera mount or robotic claw.

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The SG90 operates within a voltage range of 4.8V to 6V, making it easily compatible with the ESP32. It consumes minimal current, which is ideal for battery-powered or low-power applications. With a plastic gear system, it is designed for lighter tasks, but it can achieve an angular range of 180°, controlled via PWM signals from the ESP32.

SG90 Technical Specs #

• Type: Micro servo motor.
• Torque: ~1.8 kg/cm (at 4.8V).
• Weight: ~9 grams.
• Operating Voltage: 4.8V - 6V.
• Current Consumption:
  • At idle: ~10mA.
  • Under load: ~100-200mA.
• PWM Control:
  • Pulse Width Range: 500 µs - 2400 µs.
  • Angle Range: ~0° to 180°.
• Gears: Plastic.
• Dimensions: 22.8mm x 12.2mm x 29.0mm.
• Speed: 0.12s/60° (at 4.8V).

MG90S #

The MG90S is a step up from the SG90, offering metal gears for increased durability and torque. With a torque rating of ~2.2 kg/cm, the MG90S is suited for medium-duty applications. It retains a similar size to the SG90, making it compact enough for projects with limited space.

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Operating at 4.8V to 6V, the MG90S provides better load handling than the SG90 while remaining compatible with the ESP32's PWM outputs. Its metal gear system ensures it can withstand more wear and tear, making it a reliable choice for tasks that involve repeated or prolonged use.

MG90S Technical Specs #

• Type: Micro servo motor with metal gears.
• Torque: ~2.2 kg/cm (at 4.8V).
• Weight: ~13 grams.
• Operating Voltage: 4.8V - 6V.
• Current Consumption:
  • At idle: ~10mA.
  • Under load: ~150-250mA.
• PWM Control:
  • Pulse Width Range: 500 µs - 2500 µs.
  • Angle Range: ~0° to 180°.
• Gears: Metal.
• Dimensions: 22.8mm x 12.2mm x 31.0mm.
• Speed: 0.10s/60° (at 4.8V).

MG996R #

The MG996R is a standard-size servo designed for high-torque applications. With a torque rating of ~9.4 kg/cm at 6V, it is capable of handling significantly heavier loads than both the SG90 and MG90S. This makes it a popular choice for projects that require heavy-duty performance, such as robotic arms, grippers, and even load-bearing mechanisms.

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The MG996R operates between 4.8V and 7.2V, with higher torque available at higher voltages. It draws more current than the micro servos (up to 1.5A under load), so an external power source is usually required when using it with the ESP32. Its metal gears and robust design make it highly durable for industrial and advanced robotics projects.

MG996R Technical Specs #

• Type: Standard-size servo motor with metal gears.
• Torque:
  • ~9.4 kg/cm (at 6V).
  • ~7.2 kg/cm (at 4.8V).
• Weight: ~55 grams.
• Operating Voltage: 4.8V - 7.2V.
• Current Consumption:
  • At idle: ~10mA.
  • No load: ~170mA.
  • Under load: Up to 1.5A.
• PWM Control:
  • Pulse Width Range: 500 µs - 2500 µs.
  • Angle Range: ~0° to 180°.
• Gears: Metal.
• Dimensions: 40.7mm x 19.7mm x 42.9mm.
• Speed:
  • 0.14s/60° (at 4.8V).
  • 0.11s/60° (at 6V).

Comparison SG90 vs MG90S vs MG996R #

When selecting a servo motor for an ESP32-based project, it's essential to balance torque, size, power requirements, and durability. Here's a detailed description of the comparison table to help you make the best choice:

1. SG90: Lightweight and Budget-Friendly #

The SG90 is a micro servo with modest torque (~1.8 kg/cm) and a lightweight build (~9g). It operates efficiently at 4.8V–6V with minimal current draw (~100–200mA). However, its plastic gears make it less durable under load, and it's unsuitable for heavy-duty applications. The SG90 is perfect for lightweight tasks like camera gimbals, small robotic arms, and toy projects.

Best For:

• Beginners.
• Projects requiring minimal torque and small size.
• Battery-powered setups due to its low power consumption.

2. MG90S: Durable and Versatile #

The MG90S is another micro servo, but with a higher torque (~2.2 kg/cm) and metal gears for improved durability. It offers similar voltage and current requirements as the SG90, but its stronger build allows it to handle more demanding tasks. Weighing slightly more (~13g), it strikes a balance between size, strength, and efficiency. This makes it ideal for small robotic arms, grippers, and RC vehicles.

Best For: #

• Medium-duty applications needing more durability than the SG90.
• Projects requiring compact yet robust actuators.
• Long-lasting and frequent-use scenarios.

3. MG996R: High-Torque Powerhouse #

The MG996R is a standard-size servo designed for heavy-duty applications. With a torque of ~9.4 kg/cm (at 6V) and robust metal gears, it’s capable of handling substantial loads. However, its size (~55g) and power consumption (up to 1.5A under load) require careful power management. It operates at a broader voltage range (4.8V–7.2V), making it suitable for demanding projects like robotic arms, large RC vehicles, or lifting mechanisms.

Best For: #

• Projects requiring high torque for heavy loads.
• Advanced robotics and automation tasks.
• Mechanisms with significant load-bearing requirements.

Power Considerations for Servo Motors #

When using servo motors with the ESP32, it’s crucial to provide an adequate and stable power supply. Servos draw varying amounts of current depending on their load, torque requirements, and operational conditions. Here’s a breakdown of the power considerations for the most popular servos and recommendations for handling multiple servo motors.

SG90 and MG90S #

• Both the SG90 and <MG90S are lightweight micro servos with relatively low power demands:
  • Idle current: ~10mA.
  • Operating current under moderate load: ~100-250mA.
• These servos can often be powered directly from the ESP32's onboard 3.3V or 5V pins for single-servo setups or low-load conditions.
• Key Consideration: Avoid overloading the ESP32's onboard power regulator. While powering one or two micro servos directly is feasible, larger setups require external power to prevent brownouts or erratic behavior.

MG996R #

• The MG996R, being a high-torque standard servo, draws significantly more current:
  • Idle current: ~10mA.
  • Under no load: ~170mA.
  • Under heavy load: Up to 1.5A.
• This high current demand exceeds the capacity of the ESP32’s onboard power supply. Operating the MG996R requires a stable external power supply, particularly when using multiple servos.

External Power Supply Setup for Multiple Servo Motors #

When controlling multiple servo motors, an external power source becomes essential to ensure consistent operation without overloading the ESP32 or causing voltage drops.

Basic Setup #

1. Power Source:

   • Use a DC power supply or a battery pack with a voltage range compatible with your servos (typically 5V–6V for SG90, MG90S, and MG996R).
   • Ensure the power source can supply sufficient current for all servos. For example, a 6V 5A supply can handle multiple servos comfortably.

2. Common Ground:

   • Connect the ground of the external power source to the ground of the ESP32 and PCA9685 (if used). This ensures proper signal communication.

3. Servo Power:

   • Connect the V+ and GND terminals of the servos to the external power source instead of the ESP32.
   • Use capacitors (e.g., 100 µF) across the power rails to stabilize voltage fluctuations caused by sudden servo movements.

Using PCA9685 for Large-Scale Projects #

When working on projects that require controlling multiple servo motors, such as robotic arms, hexapod robots, or automation systems, the PCA9685 PWM driver module is an essential component. It simplifies the task of generating PWM signals and managing power for multiple servos, offloading the work from the ESP32.

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The PCA9685 is an I2C-based PWM driver capable of controlling up to 16 independent PWM channels. This makes it an ideal choice for scaling up servo-based projects without increasing the complexity of wiring or overloading the ESP32's processing capabilities.

Advantages of PCA9685 #

1. 16 Independent PWM Channels:
   • Each channel can control one servo motor, allowing up to 16 servos to be controlled simultaneously.
2. Offloads PWM Generation:
   • Frees the ESP32 from generating PWM signals, reducing its processing load and improving system performance.
3. Flexible Power Management:
   • Separate V+ pin allows the use of an external power supply for servos, accommodating high-current demands without stressing the ESP32.
4. Precision Control:
   • PWM frequency can be set up to 1000 Hz with 12-bit resolution, offering smooth and precise control of servos.
5. I2C Communication:
   • Requires only two pins (SDA and SCL) from the ESP32 to control all channels, saving GPIO pins for other uses.

Conclusion #

Servo motors are essential components in robotics, automation, and IoT projects, offering precise control over angular motion. Pairing servo motors with the ESP32 opens up a world of possibilities, from simple pan-tilt mechanisms to complex robotic systems. Selecting the right servo motor—whether the lightweight SG90, the durable MG90S, or the high-torque MG996R—depends on the specific needs of your project, such as torque, size, and power requirements.

Power management plays a critical role in ensuring stable operation. While lightweight setups can often rely on the ESP32’s onboard power supply, medium and heavy-duty setups benefit significantly from external power sources. For large-scale systems involving multiple servos, the PCA9685 PWM driver provides a practical solution, simplifying control and power distribution.