The SO-101 Single Arm Electronics Kit is the servos, bus adapter, cables and clamps for one Hugging Face LeRobot SO-101 arm, either a follower with six 12 V STS3215-C018 servos or a leader with six 7.4 V STS3215 servos in the gear-ratio split LeRobot specifies.One SO-101 arm's worth of electronics with the servo split already worked out: the follower version uses six 12 V C018 servos, the leader version uses the exact mix of 7.4 V gear ratios in the LeRobot documentation. Each kit includes its own bus servo adapter, so it can run on its own or join an existing pair; add a local power supply of the voltage listed below.What can you use it for? Adding a second follower for a bimanual setup Building a follower to pair with a leader you already have (or the reverse) The arm on top of a LeKiwi mobile base Replacing a worn-out arm without buying a full pair Who is it for?SO-101 owners extending or repairing a setup, and anyone who needs exactly one arm.Compatibility Arm: SO-101 (SO-ARM101) printed parts, leader or follower Software: LeRobot so101_follower / so101_leader configs Pairs with: any SO-101 leader or follower, including Hiwonder SO-ARM101 kits Power (not included): follower 12 V ≥ 5 A; leader 7.4 V ≥ 3 A; 5.5 × 2.1 mm centre-positive Getting started: from unboxing to your first LeRobot dataset Choose follower (12 V) or leader (7.4 V) — the servos are not interchangeable between roles. Set IDs 1–6 with LeRobot's motor-setup step before assembly. Assemble on printed SO-101 parts, chain the servos, clamp the base. Calibrate the new arm and pair it with your existing leader or follower. Specifications Follower contents 6 × STS3215-C018 12 V 30 kg·cm (1:345), 1 × Waveshare Bus Servo Adapter (A), 12 × 3-pin cables (4 × 15, 4 × 20, 4 × 40 cm), 4 × 2-inch G-clamps Leader contents 6 × 7.4 V STS3215 in the LeRobot leader split — 1 × C001 (1:345, shoulder lift), 2 × C044 (1:191, base and elbow), 3 × C046 (1:147, wrist flex, wrist roll, gripper) — plus 1 × Waveshare Bus Servo Adapter (A), 12 × cables and 4 × G-clamps Each servo includes Metal main + rear horn, screws and a 15 cm 3-pin cable Who it is for A second follower for a bimanual setup, replacing a worn arm, or pairing with a leader you already own Not included 3D-printed arm parts and cameras Bought separately Follower $189.91, leader $183.91; this kit is $172.99 / $167.99 Power supply Not included. Follower: 12 V ≥ 5 A; leader: 7.4 V ≥ 3 A; 5.5 × 2.1 mm centre-positive plug Country of origin China; kitted, packed and shipped from Singapore What's in the box Follower arm (6 × 12 V C018): 6 × STS3215-C018 12 V servos with horns, screws and 15 cm cables; 1 × Waveshare Bus Servo Adapter (A); 12 × 3-pin cables; 4 × 2-inch G-clamps Leader arm (6 × 7.4 V, LeRobot ratios): 1 × STS3215-C001, 2 × C044, 3 × C046 (7.4 V) with horns, screws and 15 cm cables; 1 × Waveshare Bus Servo Adapter (A); 12 × 3-pin cables; 4 × 2-inch G-clamps Buy parts separatelySpares and add-ons for this kit: cameras, spare servos, the STS3250 upgrade and joint spares.Shipping and returnsShips from our warehouse in Singapore with tracking. Parts and accessories are charged by parcel weight, the same rates everywhere: $11.99 up to 250 g, $19.99 to 500 g, $34.99 to 1 kg and $59.99 to 2 kg. Orders over $100 that stay under 500 g ship free. Standard tracked runs 5–18 business days; DHL Express (3–5 business days) is offered at checkout if you need it sooner. Within Singapore: $6, or free over $110. Assembled robot-arm kits over 2 kg are built and calibrated to order in Singapore (dispatch in 7–10 business days) and ship worldwide at carrier cost: SingPost Speedpost Priority from $124.99 (10–14 business days) or DHL Express from $229.99 (3–5 business days), shown at checkout. 7-day returns; defective items are replaced or refunded with shipping covered. Import duties, where charged by your country, are paid by the recipient.One parcel, one shipping charge: small parts travel together, so the postage on a single 70 g servo is the same as on six of them. A 500 g parcel holds roughly six servos plus horns and cables — which is also about where an order passes $100 and ships free. If you are buying one small item, it is usually worth checking what else you will need for the same build.Frequently asked questionsFollower or leader — which do I need?The follower is the arm the policy drives (12 V, stronger). The leader is the one you move by hand during teleoperation (7.4 V, lighter feel). A bimanual setup needs two of each.Which power supply?Follower: 12 V, 5 A or more. Leader: 7.4 V, 3 A or more. Both with a 5.5 × 2.1 mm centre-positive plug. Not included because mains adapters are hard to ship internationally.Will it work with my Hiwonder SO-ARM101 leader?Yes. Same servos family, same protocol; calibrate the new arm in LeRobot and pair them.
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