AM-ARM200

AM-ARM200 is a low-cost, open-source 6+1 DoF robotic arm with a 1 kg payload, fully 3D-printable and built for embodied AI research.

Built on the open-source philosophy of SO-ARM100, it brings the platform into a new capability class while remaining easy to reproduce and affordable.

~$240 follower / ~$140 leader / ~$380 full teleoperation kit.

Looking for the complete AlohaMini robot? See the AlohaMini repository.

Updates

• [2026-05-29] URDF files coming soon

What Makes It Different

• 6+1 DoF, 1 kg payload, 52 cm reach — a capability class rarely seen at this price point
• LeRobot & AlohaMini compatible — works out of the box with the most popular open-source robot learning stack
• Fully 3D-printable — print and assemble at home in ~60 minutes
• Open source — CAD, firmware, and software included
• Low cost — ~$240 follower / ~$140 leader / ~$380 full teleoperation kit

Gallery

Bill of Materials

AM-ARM200 Follower

Item	Qty	Unit (USD)	Subtotal (USD)
Feetech STS3215 servo (12V, 1/345)	4	$16	$64
Feetech STS3095 servo (12V, 1/399)	3	$50	$150
Waveshare bus servo controller	1	$5	$5
12V 4A power supply	1	$14	$14
Bearings, fasteners, cables	—	—	~$10
3D-printed parts	—	—	self-print
Total			~$243

AM-ARM200 Leader

Item	Qty	Unit (USD)	Subtotal (USD)
Feetech STS3215 servo (5V, 1/147)	7	$16	$112
Waveshare bus servo controller	1	$5	$5
5V 4A power supply	1	$10	$10
Bearings, fasteners, cables	—	—	~$10
3D-printed parts	—	—	self-print
Total			~$137

Getting Started

1. Buy components

Order servos, controller, power supply, and small parts. See BOM.

2. Print parts

~20 hours on a standard FDM printer. See 3D printing guide.

3. Assemble

Build a leader + follower pair in ~60 minutes. See assembly guide.

4. Software setup

All software steps are in the lerobot_alohamini shared software repository. Follow the steps below in order — each links directly to the relevant section.

Step	What	Where
1	Install environment	install.md
2	Find arm ports	§1 Port Configuration
3	Calibrate arms & teleoperate	§3 Calibration
4	Record a dataset	§5 Dataset Recording
5	Train a policy	§8 Training
6	Evaluate the policy	§9 Evaluation

Advanced: patch upstream LeRobot instead of using lerobot_alohamini

If you already have a working LeRobot environment and prefer to stay on the upstream repo, you can add STS3095 support manually with two changes.

Step 1 — Register STS3095 in the motor table

In lerobot/src/lerobot/motors/feetech/tables.py, add "sts3095" to each of the five model dictionaries. STS3095 is STS-series (same protocol as STS3215), so the values mirror that motor:

MODEL_CONTROL_TABLE = {
    ...
    "sts3095": STS_SMS_SERIES_CONTROL_TABLE,   # add this
}

MODEL_RESOLUTION = {
    ...
    "sts3095": 4096,                            # add this
}

MODEL_BAUDRATE_TABLE = {
    ...
    "sts3095": STS_SMS_SERIES_BAUDRATE_TABLE,   # add this
}

MODEL_ENCODING_TABLE = {
    ...
    "sts3095": STS_SMS_SERIES_ENCODINGS_TABLE,  # add this
}

MODEL_PROTOCOL = {
    ...
    "sts3095": 0,                               # add this (STS series = protocol 0)
}

Step 2 — Update the follower robot definition

In lerobot/src/lerobot/robots/so_follower/so_follower.py, replace the motor list with the AM-ARM200's 7-motor layout (adds wrist_yaw and swaps the three high-torque joints to sts3095):

motors=(
    ("shoulder_pan",  1, "sts3095", None),
    ("shoulder_lift", 2, "sts3095", None),
    ("elbow_flex",    3, "sts3095", None),
    ("wrist_flex",    4, "sts3215", None),
    ("wrist_yaw",     5, "sts3215", None),
    ("wrist_roll",    6, "sts3215", None),
    ("gripper",       7, "sts3215", MotorNormMode.RANGE_0_100),
),

After these two edits, the rest of the LeRobot workflow (calibration, teleop, recording, training) is identical to the standard SO-ARM100 setup.

Note: lerobot_alohamini already includes both changes — use the upstream path only if you have a specific reason to avoid the fork.

Product Line

Model	Build	Servos	Target Users	Buy (CN)
AM-ARM200	Fully 3D-printed	STS3215	Makers, students, research labs	Taobao
AM-ARM200 Pro	Fully 3D-printed	Industrial STS3250	Research institutions, university labs needing higher durability	Taobao

Same software stack across both versions. AM-ARM200 remains fully open-source and self-buildable. See am-arm200-pro/ for Pro details.

Team & Contact

AM-ARM200 is created by Li Yiteng and Wu Zhiyong.

• Email: liyiteng+github@gmail.com
• WeChat: liyiteng
• Videos & tutorials: Bilibili / YouTube

Acknowledgements

• LeRobot — the software stack this arm targets
• ALOHA — the bimanual teleoperation paradigm
• SO-ARM100 — pioneered the low-cost open arm design pattern

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