Robot Arms

SO-101 Robot Arm Kit

Name: SO-101 Robot Arm Kit - 3D Printed Parts Only
Brand: RobotEd
SKU: RE-SO101-PRINT
Price: 59.95 CHF
Availability: InStock
Rating: 4.3 (11 reviews)

A curated SO-101 kit ecosystem for builders who want complete hardware, electronics only, or professionally printed structural parts.

4.3/5

11 reviews

Choose how to build it

Full KitCHF 349.95In stock · dispatches in 1–2 working daysElectronics OnlyCHF 299.95In stock · dispatches in 1–2 working days3D Printed Parts OnlyCHF 59.95In stock · ships in 1 working day

What's included

• Configured printed structural parts

Print colour

GreyRobotEd standard grey

Made to order in Switzerland. Usually dispatched within 2–4 working days.

Free shipping in Switzerland & Liechtenstein

Customer reviews

4.3/5 · 11 reviews

★★★★☆HLa · Verified purchase

Worked as advertised, i bought it because my Apartment doesnt fit a 3D Printer, and i like the documentation that came with it. cool open source project

SO-101 configuration

Exactly what is included

Component	Full Kit	Electronics Only	Printed Parts Only
Servos	6× ST3215-SE encoder-only leader units + 6× powered 12 V ST3215 follower servos	6× ST3215-SE encoder-only leader units + 6× powered 12 V ST3215 follower servos	Not included
Controllers	2× Waveshare Bus Servo Adapter (A), SKU 25514; one per arm	2× Waveshare Bus Servo Adapter (A), SKU 25514; one per arm	Not included
Printed structure	Complete leader and follower printed-part sets	Not included	Complete leader and follower printed-part sets
Power and accessories	External DC power is required. Verify the included supply models, cable counts, horns and fasteners against the package contents.	External DC power is required. Verify the included supply models, cable counts, horns and fasteners against the package contents.	Electronics not included
Assembly state	Supplied as a build kit; electronics and printed parts are not assembled	Electronics supplied for your own build	Printed, checked, and sorted; not assembled
Compatibility	SO-101 leader + follower arms and Hugging Face LeRobot	SO-101 leader + follower arms and Hugging Face LeRobot	Current SO-101 leader/follower printed structure
Dispatch	Usually dispatched within 1–2 working days	In stock; 1–2 working days	Made to order; 2–4 working days
Shipping	Free shipping to Switzerland and Liechtenstein	Free shipping to Switzerland and Liechtenstein	Free shipping to Switzerland and Liechtenstein

Electronics · Waveshare SKU 33395

Two different servo types

The electronics set has six manually moved encoder units for the leader and six powered 12 V servos for the follower. The follower motor's electrical ratings do not apply to the leader encoders.

Leader · 6× ST3215-SE

Encoder units without a motor drive; they sense positions moved by hand. Motor torque and current ratings do not apply. The SE variant's supply range, encoder resolution, and housing dimensions have not been confirmed here.

Follower · 6× ST3215, 12 V

Operating: 6–12.6 V; 12 V typical
Max stall torque 30 kg·cm at 12 V; rated load 10 kg·cm
360° encoder with 4096 positions; 345:1 metal gearbox
No-load: 0.222 s / 60° at 12 V; backlash ≤0.5°

Maximum stall torque is a short-duration peak, not a permissible continuous load.

Controllers · 2× Bus Servo Adapter (A)

Waveshare SKU 25514; one adapter per arm. USB-C or UART to the TTL serial bus. Input 9–12.6 V for ST servos; the board does not regulate voltage, so output follows input.

Detailed servo specifications and communication

ST3215 operating voltage	6–12.6 V; 12 V typical
Stall torque (short duration)	30 kg·cm @ 12 V (≈2.94 N·m)
Rated load torque	10 kg·cm @ 12 V (≈0.98 N·m)
No-load speed	0.222 s / 60°; 45 rpm @ 12 V
Current (no-load / rated / stall)	200 mA / 900 mA / 2.7 A
Gearbox / backlash	345:1 metal gears / ≤0.5°
Position feedback	360°; 4096 positions (≈0.0879° per position)
Serial communication	TTL, half-duplex; 38.4 kbit/s–1 Mbit/s; 1 Mbit/s default
Bus and feedback	Daisy-chain, 2 ports per servo; position, speed, load, voltage, current, temperature, status
Servo connector	5264-3P; GND / VCC / TTL signal
ST3215 body dimensions	45.22 × 24.72 × 35 mm
Adapter (A), SKU 25514	42 × 33 mm; 2.5 mm mounting holes; 5.5 × 2.1 mm DC barrel and screw terminal
Adapter interfaces	USB-C or UART; servo bus D/V/G; UART TX/RX/GND
Adapter voltage	No voltage regulation; output follows input. Supply must match the connected devices.

These technical values describe only the powered ST3215 follower servos. Do not infer torque, motor-current values, or the supply voltage for the ST3215-SE leader encoders from these figures.

Power-supply models and quantities, plus exact cable and accessory counts, are being checked against the package contents. Do not infer the ST3215-SE encoder power requirements from the follower motors' 12 V ratings. Manufacturer references: ST3215 Servo, Bus Servo Adapter (A), SO-ARM101 kit assembly notes.

See the SO-101