Building Robots Made Easy: Introducing Bus Servo Driver Board for Seeed Studio XIAO
Experience the next evolution in servo control with the Bus Servo Driver Board for Seeed Studio XIAO. Unlike traditional PWM that requires one signal line per servo, this compact powerhouse uses efficient bus control to manage multiple servos through a single communication line, offering real-time feedback and precise synchronization. Whether you’re building robotic arms or multi-legged robots, transform your projects with advanced features like torque monitoring, programmable acceleration, and simplified wiring architecture.
In the world of robotics, precise servo control is crucial yet often challenging. Today, we’re excited to introduce the Bus Servo Driver Board for Seeed StudioXIAO – a compact powerhouse designed to simplify robot development and enhance control precision.
This Bus Servo Driver Board supports ST/SC series servos with UART and USB dual modes. It features a 2P 3.5mm screw terminal and is designed to be compatible with the Seeed Studio XIAO boards. Ideal for robotic arms and multi-legged robots, it ensures rapid prototyping and precise control.
Key Features That Stand Out
- Dual-mode Communication: Seamlessly switch between UART and USB modes. By default, it operates in UART mode for connecting with Seeed Studio XIAO boards. If you wish to switch to USB mode, please follow our wiki guide for the necessary configuration changes.
- Multi-servo Synchronization: Control multiple servos with precise coordination
- Professional Interface Design: 2P 3.5mm power terminal and 2.5mm 3P servo connections
- XIAO Ecosystem Integration: Perfect compatibility with Seeed Studio XIAO boards
- Compact Form Factor: Only 42x25mm, ideal for space-constrained projects
Real-World Applications
Robotic Arms
Transform your robotic arm projects with precise multi-joint control. The Bus Servo Driver Board enables smooth, coordinated movements across multiple axes, essential for tasks requiring precise positioning and real-time adjustments. That’s also the reason that our AI Robotics team also included this Bus Servo Driver Board to the LeRobot collaborative kits: the SO-ARM100 Low-Cost AI Arm Servo Motor Kit and SO-ARM100 Low-Cost AI Arm Servo Motor Kit Pro. On March 22-23, 2025, we’ve also brought nearly 30 developers joining us for an Embodied AI Hackathon to build robot arms with these two SO-ARM100 kits in Mountain View, U.S, by collaborating with NVIDIA Robotics, Hugging Face, and Hackster.io at Circuit Launch workspace! All the tutroals for the hackathon projects can be found here on Hackster.
Multi-Legged Robots
Develop sophisticated hexapods and quadrupeds with synchronized leg movements. The board’s multi-servo capabilities make it ideal for implementing complex gait patterns and maintaining stable balance control.
Educational Projects
Perfect for STEM education and maker projects, the board’s user-friendly design allows students and hobbyists to quickly prototype and experiment with robotic concepts.
Bus Control vs PWM Control
PWM (Pulse Width Modulation) is a technique widely used to control servos and other electronic devices by generating a digital signal that alternates between ON (HIGH) and OFF (LOW) states at a fixed frequency, where the duration of the ON time (pulse width) determines the servo position. However, the shift from traditional PWM to bus control represents a significant advancement in servo control. Let’s break down the key differences:
Traditional PWM Control Limitations
- One Signal Line Per Servo
- Each servo requires a dedicated PWM signal line
- Complex wiring for multi-servo systems
- Limited feedback capabilities
- Increased potential for signal interference
- Communication Constraints
- Unidirectional communication only
- No real-time feedback
- Limited control parameters
- Fixed update rates
- Scaling Challenges
- Hardware complexity increases with each servo
- Limited by microcontroller PWM channels
- Difficult to synchronize multiple servos
- Resource-intensive for the main controller
Bus Control Advantages
- Efficient Communication
- Single communication line for multiple servos
- Daisy-chain connection capability
- Reduced wiring complexity
- Better signal integrity
- Enhanced Control Capabilities
- Bidirectional communication
- Real-time position feedback
- Torque monitoring
- Temperature monitoring
- Speed control
- Multiple parameter adjustments
- Advanced Features
- Unique ID addressing for each servo
- Programmable acceleration/deceleration
- Position and speed synchronization
- Built-in protection mechanisms
- Error detection and reporting
- System Scalability
- Easy addition of new servos
- Simplified wiring architecture
- Reduced controller overhead
- Better resource utilization
Where to Get Started
This Bus Servo Driver Board for Seeed Studio XIAO is now available through Seeed Studio’s official channels (Bazaar webstore, and AliExpress Store), and soon will be available on our distributors’ store too. For technical specifications, example code, and detailed documentation, visit our product page and Wiki page here.
Whether you’re building a complex robotic arm, a multi-legged robot, or an educational project, this Bus Servo Driver Board provides the control precision and ease of use you need to bring your ideas to life.
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There is an issue with this board and the wiki: it’s write” For UART: Jumper Setting (Critical): Locate the solder jumper near the UART pins. For direct UART communication, you must ensure that the two pads are connected (soldered together).” And For USB Connection it’s write “Step1: Locate the soldering jumper on the back of the board. For USB communication, you must ensure that the two pads are connected (there is a solder bridge between them). So exactly same config…aka solder blob between pad… And in the FAQ: “What happens if I set the jumper incorrectly?
The board won’t communicate properly. For direct UART communication, ensure the two pads are connected (soldered together), and for USB communication, ensure the two pads are disconnected (no solder bridge between them). You must solder/desolder the jumper pads to match the selected mode.” so again anothzer instruction. I spend more than 300 dollar to order the SO-ARM100 Low-Cost AI Arm Servo Motor Kit Pro and despite multiple email I still have no working Servo bus driver board. This piece doesn’t work for USB direct connction. MAx voltage is 12V and power in the PRO kit give 12.26v ! not serious. Don’t buy this board it doesn’t work.
Hi Prigent, I sincerely apologize for the delayed response to your concerns. First, given the timing of your comment, I wanted to check if you have already resolved this issue with our technical support team?
Let me clarify the confusion: Based on your feedback, you purchased the SO-ARM100 Pro Kit, which includes a Bus Servo Driver Board. The board in the SO-ARM100 Pro Kit comes pre-configured in USB connection mode by default – you can refer to this Kit’s dedicated wiki (https://wiki.seeedstudio.com/lerobot_so100m/) and use it directly without any additional configuration.
The wiki content you referenced is actually for the standard Bus Servo Driver Board for XIAO, which is a different version with UART connection mode by default. However, you raised a valid point about the inconsistencies in that wiki page. Our Application Engineering team has reviewed and confirmed these documentation errors. We are already working on correcting these inconsistencies. Thank you for bringing this to our attention.
Please let me know if you still need any assistance with your SO-ARM100 Pro Kit. We’re here to help ensure you get the best experience with our products.