In the steps below we explain how to assemble our flagship robot, the SO-101.
## Source the parts
Follow this [README](https://github.com/TheRobotStudio/SO-ARM100). It contains the bill of materials, with a link to source the parts, as well as the instructions to 3D print the parts,
and advice if it's your first time printing or if you don't own a 3D printer.
Before assembling, you will first need to configure your motors. To this end, we provide a nice script, so let's first install LeRobot. After configuration, we will also guide you through assembly.
## Install LeRobot
To install LeRobot follow our [Installation Guide](./installation)
## Configure motors
To configure the motors designate one bus servo adapter and 6 motors for your leader arm, and similarly the other bus servo adapter and 6 motors for the follower arm. It's convenient to label them and write on each motor if it's for the follower `F` or for the leader `L` and it's ID from 1 to 6.
You now should plug the 5V or 12V power supply to the motor bus. 5V for the STS3215 7.4V motors and 12V for the STS3215 12V motors. Note that the leader arm always uses the 7.4V motors, so watch out that you plug in the right power supply if you have 12V and 7.4V motors, otherwise you might burn your motors! Now, connect the motor bus to your computer via USB. Note that the USB doesn't provide any power, and both the power supply and USB have to be plugged in.
### Find the USB ports associated to each arm
To find the port for each bus servo adapter, run this script:
```bash
python lerobot/scripts/find_motors_bus_port.py
```
##### Example outputs of script
<hfoptions id="example">
<hfoption id="Mac">
Example output leader arm's port: `/dev/tty.usbmodem575E0031751`
Remove the usb cable from your MotorsBus and press Enter when done.
[...Disconnect follower arm and press Enter...]
The port of this MotorsBus is /dev/tty.usbmodem575E0032081
Reconnect the usb cable.
```
</hfoption>
<hfoption id="Linux">
On Linux, you might need to give access to the USB ports by running:
```bash
sudo chmod 666 /dev/ttyACM0
sudo chmod 666 /dev/ttyACM1
```
Example output leader arm port: `/dev/ttyACM0`
```bash
Finding all available ports for the MotorBus.
['/dev/ttyACM0', '/dev/ttyACM1']
Remove the usb cable from your MotorsBus and press Enter when done.
[...Disconnect leader arm and press Enter...]
The port of this MotorsBus is /dev/ttyACM0
Reconnect the usb cable.
```
Example output follower arm port: `/dev/ttyACM1`
```
Finding all available ports for the MotorBus.
['/dev/ttyACM0', '/dev/ttyACM1']
Remove the usb cable from your MotorsBus and press Enter when done.
[...Disconnect follower arm and press Enter...]
The port of this MotorsBus is /dev/ttyACM1
Reconnect the usb cable.
```
</hfoption>
</hfoptions>
#### Update config file
Now that you have your ports, update the **port** default values of [`SO101RobotConfig`](https://github.com/huggingface/lerobot/blob/main/lerobot/common/robot_devices/robots/configs.py).
You will find something like, update the `port` values with your actual motor ports:
```python
@RobotConfig.register_subclass("so101")
@dataclass
class So101RobotConfig(ManipulatorRobotConfig):
calibration_dir: str = ".cache/calibration/so101"
# `max_relative_target` limits the magnitude of the relative positional target vector for safety purposes.
# Set this to a positive scalar to have the same value for all motors, or a list that is the same length as
# the number of motors in your follower arms.
max_relative_target: int | None = None
leader_arms: dict[str, MotorsBusConfig] = field(
default_factory=lambda: {
"main": FeetechMotorsBusConfig(
port="/dev/tty.usbmodem58760431091", <-- UPDATE HERE
The follower arm uses 6x STS3215 motors with 1/345 gearing. The leader however uses three differently geared motors to make sure it can both sustain its own weight and it can be moved without requiring much force. Which motor is needed for which joint is shown in table below.
| Leader-Arm Axis | Motor | Gear Ratio |
|-----------------|:-------:|:----------:|
| Base / Shoulder Yaw | 1 | 1 / 191 |
| Shoulder Pitch | 2 | 1 / 345 |
| Elbow | 3 | 1 / 191 |
| Wrist Roll | 4 | 1 / 147 |
| Wrist Pitch | 5 | 1 / 147 |
| Gripper | 6 | 1 / 147 |
### Set motor IDs
Plug your motor in one of the two ports of the motor bus and run this script to set its ID to 1. Replace the text after --port to the corresponding control board port.
```bash
python lerobot/scripts/configure_motor.py \
--port /dev/tty.usbmodem58760432961 \
--brand feetech \
--model sts3215 \
--baudrate 1000000 \
--ID 1
```
Then unplug your motor and plug the second motor and set its ID to 2.
```bash
python lerobot/scripts/configure_motor.py \
--port /dev/tty.usbmodem58760432961 \
--brand feetech \
--model sts3215 \
--baudrate 1000000 \
--ID 2
```
Redo this process for all your motors until ID 6. Do the same for the 6 motors of the leader arm, but make sure to change the power supply if you use motors with different voltage and make sure you give the right ID to the right motor according to the table above.
Next, you'll need to calibrate your SO-101 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 SO-101 robot to work on another.
#### Manual calibration of follower arm
You will need to move the follower arm to these positions sequentially, note that the rotated position is on the right side of the robot and you have to open the gripper fully.
| 1. Middle position | 2. Zero position | 3. Rotated position | 4. Rest position |
| <img src="https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/lerobot/leader_middle.webp?raw=true" alt="SO-101 leader arm middle position" title="SO-101 leader arm middle position" style="width:100%;"> | <img src="https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/lerobot/leader_zero.webp?raw=true" alt="SO-101 leader arm zero position" title="SO-101 leader arm zero position" style="width:100%;"> | <img src="https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/lerobot/leader_rotated.webp?raw=true" alt="SO-101 leader arm rotated position" title="SO-101 leader arm rotated position" style="width:100%;"> | <img src="https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/lerobot/leader_rest.webp?raw=true" alt="SO-101 leader arm rest position" title="SO-101 leader arm rest position" style="width:100%;"> |
Run this script to launch manual calibration:
```bash
python lerobot/scripts/control_robot.py \
--robot.type=so101 \
--robot.cameras='{}' \
--control.type=calibrate \
--control.arms='["main_leader"]'
```
Congrats 🎉, 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](./getting_started_real_world_robot)
