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Servo ST3020 Metal Serial UART Bus 25kg.cm@12V Brushless High Precision w/ Programmable 360 Degrees Magnetic Encoder


This product is a dual-axis serial bus servo with high torque. It incorporates a 360° high-precision magnetic encoder, allowing for angle control within a 360° range and the angle resolution is up to 0.088°.
It can be programmatically controlled to set any angle as the servo's middle position, and it can also be switched to continuous rotation mode as a motor/stepper motor. Each servo has two interfaces, allowing them to be connected in series. In theory, up to 253 bus servos can be controlled simultaneously, and each servo can provide information about its current angle, load, voltage, mode, and other parameters. This servo is suitable for robotics projects that require closed-loop control, such as robotic arms, hexapod robots, humanoid robots, and wheeled robots.

If you want to know more about this product, please check its Wiki Page.

Note: Servo Drive is not included.


If you have any questions on this product please feel free to contact us.

*Disclaimer: The images are merely illustrative.


Product type

ST3020 serial bus servo



Rotation angle

360° (0~4095)

Position sensor resolution

0.088° (360°/4096)

Mechanism limit angle

No Limit

Working voltage

6 ~ 14 V (typ. 12V)


high precision metal gear

No-load speed

0.167sec/60° (60RPM)@12V

Encoder type

12Bits magnetic encoder

ID range

1 ~ 253


38400bps ~ 1Mbps (1Mbps by default)


Position, Load, Speed, Input Voltage, Current, Temperature

No-load current


Locked-rotor current





UART Serial Bus Control

Allows controlling up to 253 serial bus servos at the same time


Note: though one channel UART can control up to 253 serial bus servos, due to the high power of the servos, it is necessary to consider whether the power supply solution is enough when using too many servos. For reference only, the servo driver board is NOT included



Easy to use, Large Torque

Supports 6.0~14V Wide range Voltage Input, And Can Be Directly Powered By 2S or 3S lithium batteries. Up To 25kg.Cm Torque On 12V Voltage, Suitable For Building Quadruped Robots, Hexapod Walkers, Robotic Arms And Other Robotic Projects Requiring Multiple Servos




Aluminum alloy middle case + Iron-core Motor + Metal Gear Box

Adopts high-reliability Design, suitable for industrial equipments, robotics, and other application scenarios that require angle or speed closed-loop control




360° Magnetic Encoder - High Precision, Longer Lifetime

Adopts 12-bit high-precision magnetic encoding angle sensor. Compared with the carbon film potentiometer, the angle of the magnetic encoder is enlarged to 360°, and the resolution is increased by 4 times. Since there is a gap and no friction between the magnetic encoder and the radial magnet, the lifetime of the servo is effectively extended.




Acceleration Start-stop Function

The speed and acceleration values are settable to make the motion effect softer




One Button to Calibrate the Middle Position

360° installation at any position, one button to set the current position as middle position. Easy to install and debug


1. In the default program, a hotspot will be created automatically after the servo driver board is turned on. Use your mobile phone to connect to this hotspot, open the browser, and enter the IP address to enter the control interface.




2. Click Release to unlock, then turn the servo to the middle position where you need to set




3. Click Set Middle Position then confirm.




4. Turn the servo to any angle, then click Middle, and the servo will automatically return to the middle position initially set.



Two-Way Feedback

The Servo Will Provide Various Feedback Like Position, Load, Speed, Input Voltage, Current and Temperature In Real Time


* images here are for reference ONLY



Multiple operation modes suitable for more application scenarios


Angle servo mode
Default mode, the angle position is controllable at 0~360° degrees



Speed closed-loop motor mode
Motor mode, intelligently control and maintain speed when the load changes




Step mode
Can perform step motion relative to the current position



Multi-Loop angle Position control

Supports angle position control in both positive and negative directions up to 7.5 loops under the default precision setting, but the number of loops will not be saved in case of power loss. Lowering the angle resolution can double the number of control loops





All-metal servo bracket

More Convenient to Develop the Structural Components, Combination Use More Flexible



Details Introduction


Aluminum alloy middle case
Improved heat tolerance, size stability, rigidity, and mechanical performance




High strength aluminum servo wheels
Using T6061 aluminum alloy, good anti-corrosion performance




High precision copper and steel gears
The combination of the two types of gears allows the servo to work with lower working noise, and enhances its stability and mechanical performance




All-metal bracket
More convenient to combine it with other devices



Open Source Control Program

We provide the open-source web control demo of the servo driver board and a secondary development tutorial, which can be directly used for remote setting and remote control of the servo. At the same time, we also provide a 3D model for you to build your project quickly.



Outline dimensions




Resources & Services



WIKI: www.waveshare.com/wiki/ST3020_Servo



Package Content

Weight: 0.097 kg

ST3020 Servo x1




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