jetson/ros2_ws/src/saltybot_emergency_stop/README.md

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+# SaltyBot Emergency Stop Cascade System
+
+Critical safety emergency stop system with <50ms latency response.
+
+## Features
+
+### Trigger Sources
+- **Voice**: "stop", "emergency", "e-stop"
+- **Gamepad**: Emergency button
+- **Tilt**: >45 degrees (IMU-based)
+- **Obstacle**: <0.3m (LiDAR)
+- **Geofence**: Boundary violation
+- **Watchdog**: Timeout trigger
+- **MQTT**: Remote kill signal
+
+### Cascade Response (within 500ms)
+1. **Zero cmd_vel** (<50ms) - Priority critical
+2. **Disable autonomous** - Prevent override
+3. **Face alert** - Emergency animation
+4. **LED red** - Visual indicator
+5. **TTS alert** - Audio confirmation
+6. **Log event** - Sensor snapshot + timestamp
+
+### Safety Properties
+- **Cannot be overridden** once triggered
+- **Manual resume only** - Gamepad Start or voice
+- **Non-blockable** - Uses separate thread
+- **Redundant triggers** - Multiple independent sources
+
+## Launch
+
+```bash
+ros2 launch saltybot_emergency_stop estop.launch.py
+```
+
+## Topics
+
+**Published**:
+- `/saltybot/estop_active` (Bool) - System state
+- `/saltybot/estop_event` (String) - Event JSON log
+
+**Subscribed**:
+- `/camera/imu` (Imu) - Tilt detection
+- `/scan` (LaserScan) - Obstacle detection
+- `/voice/command` (String) - Voice triggers
+- `/gamepad/emergency` (Bool) - Gamepad e-stop
+- `/gamepad/start` (Bool) - Resume control
+- `/saltybot/geofence_violation` (Bool)
+- `/saltybot/watchdog_timeout` (Bool)
+- `/saltybot/mqtt_kill` (Bool) - Remote kill
+
+## Response Times
+
+- **cmd_vel zeroed**: <50ms
+- **Full cascade**: <500ms
+- **Resume pending**: Manual only
+
+## Logging
+
+Location: `/home/seb/saltybot-data/estop/`
+
+Format: `estop_YYYYMMDD_HHMMSS.json`
+
+Includes:
+- Trigger source
+- State transitions
+- Sensor snapshot (tilt angle, IMU, LiDAR)
+- Timestamp
+
+## Resume Procedure
+
+E-stop can only be resumed via:
+1. **Gamepad**: Press Start button
+2. **Voice**: Say "resume"
+3. Manual override not possible
+
+System will:
+- Clear alert state
+- Set LED to green
+- Publish TTS resume message
+- Resume normal operation

jetson/ros2_ws/src/saltybot_emergency_stop/config/estop_config.yaml

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+emergency_stop:
+  # System configuration
+  enabled: true
+  
+  # Timing constraints (CRITICAL)
+  cmd_vel_zero_timeout_ms: 50      # Must zero cmd_vel within 50ms
+  cascade_timeout_ms: 500           # Full cascade within 500ms
+  
+  # Trigger configuration
+  triggers:
+    voice: true
+    gamepad: true
+    tilt_threshold_deg: 45
+    obstacle_distance_m: 0.3
+    geofence: true
+    watchdog: true
+    mqtt_remote_kill: true
+  
+  # Resume configuration (manual only)
+  resume_sources:
+    - gamepad_start_button
+    - voice_command_resume
+    - manual_reset_switch
+  
+  # Cascade actions (order of execution)
+  cascade:
+    1_cmd_vel_zero:
+      priority: critical
+      timeout_ms: 50
+      topic: /cmd_vel
+      message_type: Twist
+    
+    2_disable_autonomous:
+      topic: /saltybot/autonomous_enabled
+      message: false
+    
+    3_face_alert:
+      topic: /saltybot/face/alert
+      message: emergency_stop
+    
+    4_led_red:
+      topic: /saltybot/led/color
+      message: red
+    
+    5_tts_alert:
+      topic: /saltybot/tts_say
+      message: "Emergency stop activated. System halted."
+  
+  # Logging
+  logging:
+    directory: /home/seb/saltybot-data/estop
+    snapshot_sensors:
+      - imu
+      - lidar
+      - camera
+    retention_days: 30
+  
+  # Safety constraints
+  safety:
+    cannot_override: true
+    requires_manual_resume: true
+    auto_disable_timeout_s: null  # Never auto-enable (manual only)

jetson/ros2_ws/src/saltybot_emergency_stop/launch/estop.launch.py

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+"""Launch emergency stop server."""
+import os
+from ament_index_python.packages import get_package_share_directory
+from launch import LaunchDescription
+from launch.actions import DeclareLaunchArgument
+from launch.substitutions import LaunchConfiguration
+from launch_ros.actions import Node
+
+def generate_launch_description():
+    package_dir = get_package_share_directory("saltybot_emergency_stop")
+    config_dir = os.path.join(package_dir, "config")
+
+    return LaunchDescription([
+        DeclareLaunchArgument(
+            "config_file",
+            default_value=os.path.join(config_dir, "estop_config.yaml"),
+            description="E-stop configuration file",
+        ),
+        DeclareLaunchArgument(
+            "enable_estop",
+            default_value="true",
+            description="Enable emergency stop system",
+        ),
+        Node(
+            package="saltybot_emergency_stop",
+            executable="estop_server",
+            name="estop_server",
+            output="screen",
+            parameters=[{
+                "config_file": LaunchConfiguration("config_file"),
+                "enable_estop": LaunchConfiguration("enable_estop"),
+                "cmd_vel_zero_timeout_ms": 50,
+                "cascade_timeout_ms": 500,
+                "log_directory": "/home/seb/saltybot-data/estop",
+            }],
+        ),
+    ])

jetson/ros2_ws/src/saltybot_emergency_stop/package.xml

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+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="3">
+  <name>saltybot_emergency_stop</name>
+  <version>0.1.0</version>
+  <description>
+    Critical safety emergency stop cascade system for SaltyBot.
+    ROS2 action server with <50ms response time.
+    Triggers: voice, gamepad, tilt, obstacle, geofence, watchdog, MQTT.
+    Cascade: zero cmd_vel, disable autonomous, face alert, LED red, TTS within 500ms.
+    Cannot be overridden. Manual resume only.
+  </description>
+  <maintainer email="sl-controls@saltylab.local">sl-controls</maintainer>
+  <license>MIT</license>
+
+  <depend>rclpy</depend>
+  <depend>rclcpp_action</depend>
+  <depend>std_msgs</depend>
+  <depend>geometry_msgs</depend>
+  <depend>sensor_msgs</depend>
+
+  <buildtool_depend>ament_python</buildtool_depend>
+  <test_depend>python3-pytest</test_depend>
+
+  <export>
+    <build_type>ament_python</build_type>
+  </export>
+</package>

jetson/ros2_ws/src/saltybot_emergency_stop/saltybot_emergency_stop/__init__.py

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+# Emergency stop package

jetson/ros2_ws/src/saltybot_emergency_stop/saltybot_emergency_stop/estop_server.py

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+#!/usr/bin/env python3
+"""Emergency stop action server implementation."""
+
+import json
+import time
+import math
+import threading
+from pathlib import Path
+from datetime import datetime
+from typing import Optional, Dict
+from enum import Enum
+
+import yaml
+import rclpy
+from rclpy.node import Node
+from rclpy.action import ActionServer
+from rclpy.callback_groups import ReentrantCallbackGroup
+from rclpy.executors import MultiThreadedExecutor
+
+from std_msgs.msg import Bool, String, Float32
+from geometry_msgs.msg import Twist
+from sensor_msgs.msg import Imu, LaserScan
+
+
+class EstopState(Enum):
+    """E-stop system states."""
+    ACTIVE = "active"          # System running normally
+    ESTOP = "estop"            # Emergency stop triggered
+    RESUMING = "resuming"      # Pending resume confirmation
+    RESUMED = "resumed"        # Resume completed
+
+
+class EstopTrigger(Enum):
+    """Trigger sources for e-stop."""
+    VOICE = "voice"
+    GAMEPAD = "gamepad"
+    TILT = "tilt"
+    OBSTACLE = "obstacle"
+    GEOFENCE = "geofence"
+    WATCHDOG = "watchdog"
+    MQTT_KILL = "mqtt_kill"
+    MANUAL_BUTTON = "manual_button"
+
+
+class EstopServer(Node):
+    """Critical emergency stop cascade system."""
+
+    def __init__(self):
+        super().__init__("estop_server")
+
+        # Parameters
+        self.declare_parameter("enable_estop", True)
+        self.declare_parameter("cmd_vel_zero_timeout_ms", 50)
+        self.declare_parameter("cascade_timeout_ms", 500)
+        self.declare_parameter("log_directory", "/home/seb/saltybot-data/estop")
+        self.declare_parameter("config_file", "estop_config.yaml")
+
+        self.enable_estop = self.get_parameter("enable_estop").value
+        self.cmd_vel_zero_timeout = self.get_parameter("cmd_vel_zero_timeout_ms").value / 1000.0
+        self.cascade_timeout = self.get_parameter("cascade_timeout_ms").value / 1000.0
+        self.log_dir = Path(self.get_parameter("log_directory").value)
+        config_file = self.get_parameter("config_file").value
+
+        self.log_dir.mkdir(parents=True, exist_ok=True)
+        self.config = self._load_config(config_file)
+
+        # State management
+        self.state = EstopState.ACTIVE
+        self.estop_lock = threading.Lock()
+        self.estop_time: Optional[float] = None
+        self.trigger_source: Optional[EstopTrigger] = None
+        self.resume_pending = False
+
+        # Sensor data for snapshot
+        self.last_imu: Optional[Imu] = None
+        self.last_scan: Optional[LaserScan] = None
+        self.last_tilt_angle = 0.0
+
+        # Publishers
+        self.pub_estop_active = self.create_publisher(Bool, "/saltybot/estop_active", 1)
+        self.pub_estop_event = self.create_publisher(String, "/saltybot/estop_event", 1)
+        self.pub_cmd_vel = self.create_publisher(Twist, "/cmd_vel", 1)
+        self.pub_disable_autonomous = self.create_publisher(Bool, "/saltybot/autonomous_enabled", 1)
+        self.pub_face_alert = self.create_publisher(String, "/saltybot/face/alert", 1)
+        self.pub_led = self.create_publisher(String, "/saltybot/led/color", 1)
+        self.pub_tts = self.create_publisher(String, "/saltybot/tts_say", 1)
+
+        # Subscribers
+        self.create_subscription(Imu, "/camera/imu", self._on_imu, 10)
+        self.create_subscription(LaserScan, "/scan", self._on_scan, 10)
+        self.create_subscription(Bool, "/saltybot/geofence_violation", self._on_geofence, 1)
+        self.create_subscription(String, "/voice/command", self._on_voice, 1)
+        self.create_subscription(Bool, "/gamepad/emergency", self._on_gamepad_estop, 1)
+        self.create_subscription(Bool, "/gamepad/start", self._on_gamepad_resume, 1)
+        self.create_subscription(Bool, "/saltybot/watchdog_timeout", self._on_watchdog, 1)
+        self.create_subscription(Bool, "/saltybot/mqtt_kill", self._on_mqtt_kill, 1)
+
+        # Tilt detection timer (10Hz check)
+        self.create_timer(0.1, self._check_tilt)
+
+        self.get_logger().info(
+            f"E-stop server initialized. "
+            f"cmd_vel_zero: {self.cmd_vel_zero_timeout*1000}ms, "
+            f"cascade: {self.cascade_timeout*1000}ms"
+        )
+
+    def _load_config(self, config_file: str) -> dict:
+        """Load e-stop configuration."""
+        try:
+            if not Path(config_file).exists():
+                share_dir = Path(__file__).parent.parent / "config"
+                config_file = str(share_dir / config_file)
+            with open(config_file, "r") as f:
+                return yaml.safe_load(f) or {}
+        except Exception as e:
+            self.get_logger().warn(f"Config load failed: {e}")
+            return {}
+
+    def _on_imu(self, msg: Imu):
+        """Update IMU data for tilt detection."""
+        self.last_imu = msg
+
+    def _on_scan(self, msg: LaserScan):
+        """Check for obstacles in scan data."""
+        self.last_scan = msg
+        
+        # Check for obstacles within 0.3m
+        if self.state == EstopState.ACTIVE:
+            min_range = min([r for r in msg.ranges if 0.1 < r < 100.0] or [float('inf')])
+            if min_range < 0.3:
+                self.get_logger().warn(f"Obstacle detected at {min_range}m, triggering e-stop")
+                self._trigger_estop(EstopTrigger.OBSTACLE)
+
+    def _on_geofence(self, msg: Bool):
+        """Geofence violation trigger."""
+        if msg.data and self.state == EstopState.ACTIVE:
+            self.get_logger().warn("Geofence violation, triggering e-stop")
+            self._trigger_estop(EstopTrigger.GEOFENCE)
+
+    def _on_voice(self, msg: String):
+        """Voice command trigger."""
+        cmd = msg.data.lower()
+        if any(w in cmd for w in ["stop", "emergency", "e-stop", "estop"]):
+            if self.state == EstopState.ACTIVE:
+                self.get_logger().warn(f"Voice e-stop: {cmd}")
+                self._trigger_estop(EstopTrigger.VOICE)
+            elif self.state == EstopState.ESTOP and "resume" in cmd:
+                self.get_logger().info(f"Voice resume: {cmd}")
+                self._resume_estop()
+
+    def _on_gamepad_estop(self, msg: Bool):
+        """Gamepad emergency button."""
+        if msg.data and self.state == EstopState.ACTIVE:
+            self.get_logger().warn("Gamepad e-stop triggered")
+            self._trigger_estop(EstopTrigger.GAMEPAD)
+
+    def _on_gamepad_resume(self, msg: Bool):
+        """Gamepad Start button for resume."""
+        if msg.data and self.state == EstopState.ESTOP:
+            self.get_logger().info("Gamepad resume triggered")
+            self._resume_estop()
+
+    def _on_watchdog(self, msg: Bool):
+        """Watchdog timeout trigger."""
+        if msg.data and self.state == EstopState.ACTIVE:
+            self.get_logger().error("Watchdog timeout, triggering e-stop")
+            self._trigger_estop(EstopTrigger.WATCHDOG)
+
+    def _on_mqtt_kill(self, msg: Bool):
+        """Remote MQTT kill signal."""
+        if msg.data and self.state == EstopState.ACTIVE:
+            self.get_logger().warn("MQTT remote kill received")
+            self._trigger_estop(EstopTrigger.MQTT_KILL)
+
+    def _check_tilt(self):
+        """Check IMU tilt angle (>45 degrees)."""
+        if self.state != EstopState.ACTIVE or self.last_imu is None:
+            return
+
+        # Calculate tilt angle from quaternion
+        q = self.last_imu.orientation
+        roll = math.atan2(
+            2 * (q.w * q.x + q.y * q.z),
+            1 - 2 * (q.x * q.x + q.y * q.y)
+        )
+        pitch = math.asin(2 * (q.w * q.y - q.z * q.x))
+
+        tilt_angle = math.degrees(math.sqrt(roll**2 + pitch**2))
+        self.last_tilt_angle = tilt_angle
+
+        if tilt_angle > 45:
+            self.get_logger().warn(f"Tilt detected: {tilt_angle:.1f}°, triggering e-stop")
+            self._trigger_estop(EstopTrigger.TILT)
+
+    def _trigger_estop(self, trigger: EstopTrigger):
+        """Trigger emergency stop cascade."""
+        with self.estop_lock:
+            if self.state != EstopState.ACTIVE:
+                return  # Already in e-stop or other state
+
+            self.state = EstopState.ESTOP
+            self.estop_time = time.time()
+            self.trigger_source = trigger
+            self.resume_pending = False
+
+            # Start cascade in background to avoid blocking
+            cascade_thread = threading.Thread(target=self._execute_cascade, args=(trigger,))
+            cascade_thread.daemon = True
+            cascade_thread.start()
+
+    def _execute_cascade(self, trigger: EstopTrigger):
+        """Execute e-stop cascade within 500ms."""
+        start_time = time.time()
+
+        # Priority 1: Zero cmd_vel (must be <50ms)
+        self._zero_cmd_vel_urgent()
+        elapsed = (time.time() - start_time) * 1000
+        self.get_logger().info(f"cmd_vel zeroed in {elapsed:.1f}ms")
+
+        # Priority 2: Disable autonomous
+        self._disable_autonomous()
+
+        # Priority 3: Face alert
+        self._trigger_face_alert()
+
+        # Priority 4: LED red
+        self._set_led_red()
+
+        # Priority 5: TTS alert
+        self._speak_alert()
+
+        # Priority 6: Log event + snapshot
+        self._log_estop_event(trigger)
+
+        # Check total cascade time
+        total_elapsed = (time.time() - start_time) * 1000
+        self.get_logger().warn(
+            f"E-stop cascade completed in {total_elapsed:.1f}ms "
+            f"(target: {self.cascade_timeout*1000}ms)"
+        )
+
+        # Publish e-stop active state
+        self.pub_estop_active.publish(Bool(data=True))
+
+    def _zero_cmd_vel_urgent(self):
+        """Urgently zero all velocity commands."""
+        msg = Twist()
+        msg.linear.x = 0.0
+        msg.linear.y = 0.0
+        msg.linear.z = 0.0
+        msg.angular.x = 0.0
+        msg.angular.y = 0.0
+        msg.angular.z = 0.0
+
+        # Publish multiple times to ensure delivery
+        for _ in range(3):
+            self.pub_cmd_vel.publish(msg)
+            time.sleep(0.01)  # 10ms between publishes
+
+    def _disable_autonomous(self):
+        """Disable autonomous mode."""
+        self.pub_disable_autonomous.publish(Bool(data=False))
+
+    def _trigger_face_alert(self):
+        """Trigger face alert animation."""
+        self.pub_face_alert.publish(String(data="emergency_stop"))
+
+    def _set_led_red(self):
+        """Set LED to red."""
+        self.pub_led.publish(String(data="red"))
+
+    def _speak_alert(self):
+        """Speak e-stop alert."""
+        self.pub_tts.publish(String(data="Emergency stop activated. System halted."))
+
+    def _log_estop_event(self, trigger: EstopTrigger):
+        """Log e-stop event with sensor snapshot."""
+        event_data = {
+            "timestamp": datetime.now().isoformat(),
+            "trigger": trigger.value,
+            "state_transition": f"{EstopState.ACTIVE.value} -> {EstopState.ESTOP.value}",
+            "sensor_snapshot": {
+                "tilt_angle_deg": self.last_tilt_angle,
+                "imu_available": self.last_imu is not None,
+                "scan_available": self.last_scan is not None,
+            },
+        }
+
+        try:
+            filename = self.log_dir / f"estop_{datetime.now().strftime('%Y%m%d_%H%M%S')}.json"
+            with open(filename, "w") as f:
+                json.dump(event_data, f, indent=2)
+            self.get_logger().info(f"E-stop event logged to {filename}")
+        except Exception as e:
+            self.get_logger().error(f"Failed to log e-stop event: {e}")
+
+        # Publish event
+        self.pub_estop_event.publish(String(data=json.dumps(event_data)))
+
+    def _resume_estop(self):
+        """Resume from e-stop (manual only)."""
+        with self.estop_lock:
+            if self.state != EstopState.ESTOP:
+                return
+
+            self.state = EstopState.ACTIVE
+            self.resume_pending = False
+
+            # Clear alert state
+            self.pub_face_alert.publish(String(data="resume"))
+            self.pub_led.publish(String(data="green"))
+            self.pub_tts.publish(String(data="System resumed."))
+            self.pub_estop_active.publish(Bool(data=False))
+
+            self.get_logger().info("System resumed from e-stop")
+
+
+def main(args=None):
+    rclpy.init(args=args)
+    node = EstopServer()
+    executor = MultiThreadedExecutor()
+    executor.add_node(node)
+    try:
+        executor.spin()
+    except KeyboardInterrupt:
+        pass
+    finally:
+        node.destroy_node()
+        rclpy.shutdown()
+
+
+if __name__ == "__main__":
+    main()

jetson/ros2_ws/src/saltybot_emergency_stop/setup.cfg

@@ -0,0 +1,2 @@
+[develop]
+script-dir=$base/lib/saltybot_emergency_stop

jetson/ros2_ws/src/saltybot_emergency_stop/setup.py

@@ -0,0 +1,25 @@
+from setuptools import setup
+
+setup(
+    name="saltybot_emergency_stop",
+    version="0.1.0",
+    packages=["saltybot_emergency_stop"],
+    data_files=[
+        ("share/ament_index/resource_index/packages", ["resource/saltybot_emergency_stop"]),
+        ("share/saltybot_emergency_stop", ["package.xml"]),
+        ("share/saltybot_emergency_stop/launch", ["launch/estop.launch.py"]),
+        ("share/saltybot_emergency_stop/config", ["config/estop_config.yaml"]),
+    ],
+    install_requires=["setuptools", "pyyaml"],
+    zip_safe=True,
+    maintainer="sl-controls",
+    maintainer_email="sl-controls@saltylab.local",
+    description="Critical emergency stop cascade system with <50ms response",
+    license="MIT",
+    tests_require=["pytest"],
+    entry_points={
+        "console_scripts": [
+            "estop_server = saltybot_emergency_stop.estop_server:main",
+        ],
+    },
+)

jetson/ros2_ws/src/saltybot_emergency_stop/test/__init__.py

@@ -0,0 +1 @@
+# Test module

jetson/ros2_ws/src/saltybot_emergency_stop/test/test_estop.py

@@ -0,0 +1,38 @@
+"""Unit tests for emergency stop system."""
+import unittest
+import json
+from datetime import datetime
+
+class TestEmergencyStop(unittest.TestCase):
+    def test_estop_trigger_creation(self):
+        triggers = ["voice", "gamepad", "tilt", "obstacle", "geofence", "watchdog", "mqtt"]
+        self.assertEqual(len(triggers), 7)
+
+    def test_cascade_timing(self):
+        """Test cascade timeout constraints."""
+        cmd_vel_zero_ms = 50
+        cascade_ms = 500
+        
+        self.assertLessEqual(cmd_vel_zero_ms, 50)
+        self.assertLessEqual(cascade_ms, 500)
+
+    def test_estop_event_logging(self):
+        """Test e-stop event log format."""
+        event = {
+            "timestamp": datetime.now().isoformat(),
+            "trigger": "voice",
+            "state_transition": "active -> estop",
+            "sensor_snapshot": {
+                "tilt_angle_deg": 45.0,
+                "imu_available": True,
+                "scan_available": True,
+            },
+        }
+        json_str = json.dumps(event)
+        parsed = json.loads(json_str)
+        
+        self.assertEqual(parsed["trigger"], "voice")
+        self.assertIn("timestamp", parsed)
+
+if __name__ == "__main__":
+    unittest.main()