Hardware Overview

Overview

This section describes the complete hardware architecture of Pixel Robot, including its mechanical structure, compute units, sensors, electronics, and power system.

Hardware Architecture

Pixel Robot follows a layered hardware design:

  • Compute Layer – Runs high-level ROS 2 software
  • Control Layer – Handles real-time motor control and odometry
  • Sensor Layer – Provides perception and environment awareness
  • Power Layer – Supplies regulated power to all subsystems

Each layer is designed to be independent and modular.

Mechanical Design

Mechanical Design

Chassis

  • Differential-drive mobile base
  • Rigid frame with mounting points for:
  • Compute unit
  • Battery
  • Motor controller
  • Sensors
  • Passive caster wheel for balance
  • Compact footprint for indoor navigation

Drive System

  • Two DC gear motors
  • Quadrature wheel encoders
  • Rubber wheels for traction
  • Encoder feedback used for odometry and closed-loop control

Compute Unit

Main Controller

Raspberry Pi

  • Raspberry Pi 4B (8GB RAM)
  • Runs Ubuntu 22.04 LTS
  • Hosts all ROS 2 nodes
  • Handles:
  • SLAM and localization
  • Navigation and planning
  • Perception pipelines
  • User interfaces and visualization

Connectivity

  • USB interfaces for sensors and microcontroller
  • WiFi and Ethernet for remote access
  • GPIO headers for expansion

Control Electronics

Motor Controller (Custom Momentum Robotics Compute Board)

Momentum LLC Board

  • Custom Momentum Robotics Compute board based on ESP32 S3
  • Purpose-built for low-level motor control and real-time operations
  • ESP32 S3 MCU for real-time control
  • Responsibilities:
  • Motor PWM control
  • PID velocity control
  • Encoder reading
  • Odometry computation
  • Communicates with the compute unit via serial interface
  • Publishes odometry and receives velocity commands through ROS 2

Sensor Suite

2D LIDAR

Lidar

  • 360° scanning range
  • Used for:
  • Mapping (SLAM)
  • Localization
  • Obstacle detection
  • Publishes laser scan data to ROS 2

Camera Systems

The camera configuration depends on the robot variant:

Variant V1

  • No camera
  • Navigation relies solely on LIDAR and odometry

Variant V2

Pi Cam

  • Raspberry Pi Camera
  • Used for:
  • Object detection
  • Vision-based perception
  • Image processing pipelines

Variant V3

Realsense Camera

  • Intel RealSense depth camera
  • Provides:
  • RGB images
  • Depth data
  • 3D perception capabilities

Power System

Battery

  • 11.1V 2500mAh NMC (Lithium Nickel Manganese Cobalt Oxide)
  • Rechargeable lithium-based battery
  • Provides sufficient capacity for extended operation
  • Mounted securely within the chassis

Power Distribution

  • Main battery output distributed to:
  • Motor driver circuitry
  • Compute unit via voltage regulator
  • Sensors and peripherals
  • Separate regulated rails to ensure stable operation

Voltage Regulation

  • Step-down regulators used to supply:
  • 5V for compute unit and logic
  • Motor voltage as required by motors
  • Designed to handle peak current during motor startup

Power Management & Safety

  • Power switch for safe startup and shutdown
  • Inline protection (fuse or current limiter)
  • Reverse polarity and overcurrent protection

Charging System

  • Dedicated charging port
  • Charging circuit includes:
  • Overvoltage protection
  • Overcurrent protection
  • Thermal safety mechanisms

Expansion & Customization

Pixel Robot is designed for extensibility:

  • USB ports for additional sensors
  • GPIO access for custom electronics
  • Mounting space for:
  • Extra sensors
  • Displays
  • External controllers

This makes the platform suitable for both educational use and advanced research.

You now have a complete overview of Pixel Robot’s hardware platform 🚀