Reachy Mini: Humanoid Companion & AI Agent

Reachy Mini by Pollen Robotics is a highly expressive, open-source humanoid desktop robot. Equipped with the revolutionary 3-DOF Orbita Joint, animated LCD eyes, and a lightweight robot arm, Reachy Mini serves as an ideal platform for exploring social robotics, Embodied AI, and interactive controls.

Orbita Head & Expressive Mechanism

Animated LCD Eyes

Dual circular LCD displays render dynamic pupil movement, blinks, and emotions.

Orbita 3-DOF Neck

Patented parallel mechanism allows smooth pitch, roll, and yaw with speed and agility.

Embodied Integration

Designed to serve as a physical avatar for Large Language Models (LLMs) and vision systems.

Hardware & Specification

Reachy Mini is powered by a central computer (Raspberry Pi 4 or Raspberry Pi 5) connected to smart motor buses and a control board. Below is the reference architecture specification:

Subsystem	Specification Details	Interface Type
Processor Core	Raspberry Pi 4B (4GB/8GB) / Raspberry Pi 5	Broadcom SOC / PCIe
Neck Actuators	3x Custom servos with parallel linkage	USB-to-Serial Bus (Dynamixel Protocol)
Arm Joints	XL-320 or XL-430 smart serial servos	Half-Duplex TTL Bus
Vision Sensor	Wide-angle USB camera module in chest/head	UVC Driver (V4L2)
LCD Screens	2x SPI GC9A01 1.28-inch circular screens	SPI Bus (GPIO)

Pro-Tip: The parallel linkages of the Orbita head must be calibrated symmetrically. An uncalibrated head can cause motor binding and trigger safety shutoffs.

SDK & System Setup

You can run controls directly on Reachy Mini or connect remotely over gRPC using the python library.

Bash

# Create virtual environment
python3 -m venv reachy_env
source reachy_env/bin/activate

# Install reachy-sdk
pip install reachy-sdk --upgrade

# Install extra dependencies for simulation support
pip install reachy-sdk[sim] pyovspace numpy

Python SDK Control Code

The following Python script connects to Reachy Mini and demonstrates basic head tracking/orientation commands using the SDK:

Python

import time
from reachy_sdk import ReachySDK

# Connect to Reachy Mini (use local IP or localhost in sim)
reachy = ReachySDK(host='192.168.1.100')

# Enable motor torque
reachy.turn_on('head')

print("Sending neck orientation commands...")
# Move Orbita neck to look straight with subtle tilt
reachy.head.look_at(x=1.0, y=0.0, z=0.2, duration=2.0)
time.sleep(2.0)

# Tilt right
reachy.head.look_at(x=1.0, y=-0.3, z=0.0, duration=1.5)
time.sleep(2.0)

# Tilt left
reachy.head.look_at(x=1.0, y=0.3, z=0.0, duration=1.5)
time.sleep(2.0)

# Reset position
reachy.head.look_at(x=1.0, y=0.0, z=0.0, duration=1.0)
time.sleep(1.0)

# Safely turn off torque
reachy.turn_off('head')
print("Completed successfully!")

Troubleshooting (FAQ)

Verify the SPI wiring and power connections on the GPIO header. Ensure that SPI interface is enabled in your Raspberry Pi configuration (sudo raspi-config).

Check if the reachy server daemon is running on the robot using: systemctl status reachy_sdk_server. Also ensure both your control PC and the robot are on the same local network subnet.

Citations & Resources

Reachy Mini is developed by Pollen Robotics under open-source hardware/software licenses. For resources, documentation, and assemblies, visit:

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