In the steps below, we explain how to assemble the SO-100 robot.
Follow this README. It contains the bill of materials, with a link to source the parts, as well as the instructions to 3D print the parts. And advise if it’s your first time printing or if you don’t own a 3D printer.
To install LeRobot, follow our Installation Guide
In addition to these instructions, you need to install the Feetech SDK:
pip install -e ".[feetech]"Note: Unlike the SO-101, the motor connectors are not easily accessible once the arm is assembled, so the configuration step must be done beforehand.
To find the port for each bus servo adapter, run this script:
python -m lerobot.find_port
Example output:
Finding all available ports for the MotorBus.
['/dev/tty.usbmodem575E0032081', '/dev/tty.usbmodem575E0031751']
Remove the USB cable from your MotorsBus and press Enter when done.
[...Disconnect corresponding leader or follower arm and press Enter...]
The port of this MotorsBus is /dev/tty.usbmodem575E0032081
Reconnect the USB cable.Where the found port is: /dev/tty.usbmodem575E0032081 corresponding to your leader or follower arm.
Each motor is identified by a unique id on the bus. When brand new, motors usually come with a default id of 1. For the communication to work properly between the motors and the controller, we first need to set a unique, different id to each motor. Additionally, the speed at which data is transmitted on the bus is determined by the baudrate. In order to talk to each other, the controller and all the motors need to be configured with the same baudrate.
To that end, we first need to connect to each motor individually with the controller in order to set these. Since we will write these parameters in the non-volatile section of the motors’ internal memory (EEPROM), we’ll only need to do this once.
If you are repurposing motors from another robot, you will probably also need to perform this step as the ids and baudrate likely won’t match.
Connect the usb cable from your computer and the power supply to the follower arm’s controller board. Then, run the following command or run the API example with the port you got from the previous step. You’ll also need to give your leader arm a name with the id parameter.
For a visual reference on how to set the motor ids please refer to this video where we follow the process for the SO101 arm.
python -m lerobot.setup_motors \
--robot.type=so100_follower \
--robot.port=/dev/tty.usbmodem585A0076841 # <- paste here the port found at previous stepYou should see the following instruction
Connect the controller board to the 'gripper' motor only and press enter.As instructed, plug the gripper’s motor. Make sure it’s the only motor connected to the board, and that the motor itself is not yet daisy-chained to any other motor. As you press [Enter], the script will automatically set the id and baudrate for that motor.
If you get an error at that point, check your cables and make sure they are plugged in properly:
If you are using a Waveshare controller board, make sure that the two jumpers are set on the B channel (USB).
You should then see the following message:
'gripper' motor id set to 6Followed by the next instruction:
Connect the controller board to the 'wrist_roll' motor only and press enter.You can disconnect the 3-pin cable from the controller board, but you can leave it connected to the gripper motor on the other end, as it will already be in the right place. Now, plug in another 3-pin cable to the wrist roll motor and connect it to the controller board. As with the previous motor, make sure it is the only motor connected to the board and that the motor itself isn’t connected to any other one.
Repeat the operation for each motor as instructed.
Check your cabling at each step before pressing Enter. For instance, the power supply cable might disconnect as you manipulate the board.
When you are done, the script will simply finish, at which point the motors are ready to be used. You can now plug the 3-pin cable from each motor to the next one, and the cable from the first motor (the ‘shoulder pan’ with id=1) to the controller board, which can now be attached to the base of the arm.
Do the same steps for the leader arm.
python -m lerobot.setup_motors \
--teleop.type=so100_leader \
--teleop.port=/dev/tty.usbmodem575E0031751 # <- paste here the port found at previous stepFollow the video for removing gears. You need to remove the gear for the motors of the leader arm. As a result, you will only use the position encoding of the motor and reduce friction to more easily operate the leader arm.
Remove all support material from the 3D-printed parts. The easiest way to do this is using a small screwdriver to get underneath the support material.
Note: This video provides visual guidance for assembling the arms, but it doesn’t specify when or how to do the wiring. Inserting the cables beforehand is much easier than doing it afterward. The first arm may take a bit more than 1 hour to assemble, but once you get used to it, you can assemble the second arm in under 1 hour.
Step 2: Insert Wires
Step 3: Install in Base
Step 4: Secure Motor
Step 5: Attach Motor Holder
Step 6: Attach Motor Horns
Step 7: Attach Shoulder Part
Step 8: Secure Shoulder
Step 9: Install Motor 2
Step 10: Attach Shoulder Holder

Step 11: Secure Motor 2
Step 12: Attach Motor Horn
Step 13: Attach Base
Step 14: Attach Upper Arm
Step 15: Install Motor 3
Step 16: Attach Motor Horn
Step 17: Attach Forearm
Step 18: Install Motor 4

Step 19: Attach Motor Holder 4
Step 20: Secure Motor 4 & Attach Horn
Step 21: Install Motor 5
Step 22: Attach Wrist
Step 23: Attach Wrist Horn
Step 24: Attach Gripper
Step 25: Install Gripper Motor
Step 26: Attach Gripper Horn & Claw
Step 27: Mount Controller

Assembly complete – proceed to Leader arm assembly.
For the leader configuration, perform Steps 1–23. Make sure that you removed the motor gears from the motors.
Step 24: Attach Leader Holder
Step 25: Attach Handle
Step 26: Install Gripper Motor
Step 27: Attach Trigger
Step 28: Mount Controller

Next, you’ll need to calibrate your robot to ensure that the leader and follower arms have the same position values when they are in the same physical position. The calibration process is very important because it allows a neural network trained on one robot to work on another.
Run the following command or API example to calibrate the follower arm:
python -m lerobot.calibrate \
--robot.type=so100_follower \
--robot.port=/dev/tty.usbmodem58760431551 \ # <- The port of your robot
--robot.id=my_awesome_follower_arm # <- Give the robot a unique nameWe unified the calibration method for most robots. Thus, the calibration steps for this SO100 arm are the same as the steps for the Koch and SO101. First, we have to move the robot to the position where each joint is in the middle of its range, then we press Enter. Secondly, we move all joints through their full range of motion. A video of this same process for the SO101 as reference can be found here
Do the same steps to calibrate the leader arm, run the following command or API example:
python -m lerobot.calibrate \
--teleop.type=so100_leader \
--teleop.port=/dev/tty.usbmodem58760431551 \ # <- The port of your robot
--teleop.id=my_awesome_leader_arm # <- Give the robot a unique nameCongrats 🎉, your robot is all set to learn a task on its own. Start training it by following this tutorial: Getting started with real-world robots
If you have any questions or need help, please reach out on Discord.