Python Message Library

55+ typed message classes for Python robotics. Binary-compatible with Rust, zero-copy shared memory transport.

Which messages do I need?

I'm building a...	Start with these
Mobile robot	`CmdVel`, `Odometry`, `LaserScan`, `Imu`
Robot arm	`JointState`, `JointCommand`, `WrenchStamped`, `TrajectoryPoint`
Drone	`Imu`, `NavSatFix`, `MotorCommand`, `BatteryState`
Vision system	`Image`, `Detection`, `PointCloud`, `DepthImage`
Multi-robot	`Pose2D`, `Heartbeat`, `DiagnosticStatus`, `TransformStamped`
Teleoperation	`JoystickInput`, `CmdVel`, `EmergencyStop`

Availability

All message types are available via the Rust bindings:

from horus import (
    # Geometry
    CmdVel, Pose2D, Pose3D, Twist, Vector3, Point3, Quaternion,
    TransformStamped, PoseStamped, PoseWithCovariance, TwistWithCovariance,
    Accel, AccelStamped,
    # Control
    MotorCommand, ServoCommand, DifferentialDriveCommand, PidConfig,
    TrajectoryPoint, JointCommand,
    # Sensor
    Imu, Odometry, LaserScan, JointState, BatteryState, RangeSensor,
    NavSatFix, MagneticField, Temperature, FluidPressure, Illuminance,
    Clock, TimeReference,
    # Diagnostics
    Heartbeat, DiagnosticStatus, EmergencyStop, ResourceUsage,
    DiagnosticValue, DiagnosticReport, NodeHeartbeat, SafetyStatus,
    # Force/Haptics
    WrenchStamped, ForceCommand, ContactInfo,
    ImpedanceParameters, HapticFeedback,
    # Navigation
    NavGoal, GoalResult, PathPlan, Waypoint, NavPath,
    VelocityObstacle, VelocityObstacles, OccupancyGrid, CostMap,
    # Input
    JoystickInput, KeyboardInput,
    # Detection/Perception
    BoundingBox2D, BoundingBox3D, Detection, Detection3D,
    SegmentationMask, TrackedObject, TrackingHeader,
    Landmark, Landmark3D, LandmarkArray,
    PointField, PlaneDetection, PlaneArray,
    # Vision
    CompressedImage, CameraInfo, RegionOfInterest, StereoInfo,
    # Pool-backed domain types
    Image, PointCloud, DepthImage,
)

Overview

Key Features:

Full Rust parity — All 55+ Rust message types are available in Python
Zero-copy IPC — POD types transfer via shared memory with no serialization overhead
Cross-language compatible — Binary-compatible with Rust message types
Nanosecond timestamps — All messages include timestamp_ns field
Typed Topic support — Use Topic(CmdVel) for type-safe pub/sub

Message Categories

Each category has a dedicated page with deep documentation — every method explained with narratives, code examples, and common mistakes.

Category	Types	Key Methods	Page
Geometry	Vector3, Point3, Quaternion, Pose2D, Pose3D, Twist, CmdVel, TransformStamped, covariance types, Accel	`from_euler()`, `distance_to()`, `normalize()`, `dot()`, `cross()`, `stop()`, `zero()`, `identity()`	Deep docs →
Sensor	LaserScan, Imu, Odometry, JointState, BatteryState, NavSatFix, Clock, TimeReference, + simple types	`angle_at()`, `set_orientation_from_euler()`, `is_critical()`, `distance_to()`, `position(name)`	Deep docs →
Control	MotorCommand, ServoCommand, DifferentialDriveCommand, PidConfig, TrajectoryPoint, JointCommand	`velocity()`, `from_degrees()`, `from_twist()`, `proportional()`, `pi()`, `pd()`, `add_position()`	Deep docs →
Navigation	NavGoal, NavPath, Waypoint, GoalResult, OccupancyGrid, CostMap, PathPlan	`is_reached()`, `closest_waypoint_index()`, `world_to_grid()`, `is_free()`, `calculate_progress()`	Deep docs →
Diagnostics	DiagnosticStatus, EmergencyStop, ResourceUsage, SafetyStatus, DiagnosticReport, Heartbeat	`ok()`, `warn()`, `error()`, `engage()`, `release()`, `is_cpu_high()`, `is_safe()`	Deep docs →
Force & Haptics	WrenchStamped, ForceCommand, ImpedanceParameters, HapticFeedback, ContactInfo, TactileArray	`force_magnitude()`, `exceeds_limits()`, `compliant()`, `stiff()`, `vibration()`, `surface_contact()`	Deep docs →
Perception	Detection, Detection3D, BoundingBox2D/3D, TrackedObject, Landmark, LandmarkArray, SegmentationMask, PlaneDetection	`iou()`, `is_confident()`, `confirm()`, `speed()`, `coco_pose()`, `distance_to_point()`	Deep docs →
Vision	Image, PointCloud, DepthImage, CameraInfo, CompressedImage, StereoInfo, RegionOfInterest	`to_numpy()`, `from_numpy()`, `focal_lengths()`, `depth_from_disparity()`, `contains()`	Deep docs →
Input & Audio	JoystickInput, KeyboardInput, AudioFrame	`new_button()`, `new_axis()`, `is_ctrl()`, `mono()`, `stereo()`	Deep docs →

Cross-Language Compatibility

All 55+ Python message types are binary-compatible with Rust via zero-copy shared memory:

Category	Python Classes	Count
Geometry	Pose2D, Pose3D, Twist, Vector3, Point3, Quaternion, TransformStamped, PoseStamped, PoseWithCovariance, TwistWithCovariance, Accel, AccelStamped	12
Control	CmdVel, MotorCommand, ServoCommand, DifferentialDriveCommand, PidConfig, TrajectoryPoint, JointCommand	7
Sensor	Imu, Odometry, LaserScan, JointState, BatteryState, RangeSensor, NavSatFix, MagneticField, Temperature, FluidPressure, Illuminance, Clock, TimeReference	13
Diagnostics	Heartbeat, DiagnosticStatus, EmergencyStop, ResourceUsage, DiagnosticValue, DiagnosticReport, NodeHeartbeat, SafetyStatus	8
Force/Haptics	WrenchStamped, ForceCommand, ContactInfo, ImpedanceParameters, HapticFeedback, TactileArray	6
Navigation	NavGoal, GoalResult, PathPlan, Waypoint, NavPath, VelocityObstacle, VelocityObstacles, OccupancyGrid, CostMap	9
Input	JoystickInput, KeyboardInput	2
Detection/Perception	BoundingBox2D, BoundingBox3D, Detection, Detection3D, SegmentationMask, TrackedObject, TrackingHeader, Landmark, Landmark3D, LandmarkArray, PointField, PlaneDetection, PlaneArray	13
Vision	CompressedImage, CameraInfo, RegionOfInterest, StereoInfo	4
Domain (pool)	Image, PointCloud, DepthImage	3

Example — Python to Rust:

# Python sender
from horus import Topic, Twist
topic = Topic(Twist)
topic.send(Twist(linear_x=1.0, angular_z=0.5))

// Rust receiver
use horus::prelude::*;
let topic: Topic<Twist> = Topic::new("twist")?;
if let Some(twist) = topic.recv() {
    println!("linear_x={}, angular_z={}", twist.linear[0], twist.angular[2]);
}

Usage Patterns

Robot Controller with Multiple Sensors

from horus import Node, Topic, CmdVel, LaserScan, Imu

scan_topic = Topic(LaserScan)
imu_topic = Topic(Imu)
cmd_topic = Topic(CmdVel)

def controller_tick(node):
    scan = scan_topic.recv()
    imu = imu_topic.recv()
    if scan:
        min_dist = min(scan.ranges) if scan.ranges else None
        if min_dist and min_dist < 0.5:
            cmd_topic.send(CmdVel(0.0, 0.0))  # Stop
        else:
            cmd_topic.send(CmdVel(linear=0.5, angular=0.0))

node = Node(name="controller", tick=controller_tick, rate=10)