feat: VESC CAN telemetry for dual motors (Issue #645)

New saltybot_vesc_telemetry ROS2 package — SocketCAN (python-can, can0)
telemetry for dual FSESC 6.7 Pro (FW 6.6) on CAN IDs 61 (left) and 79 (right).

- vesc_can_protocol.py: STATUS/STATUS_4/STATUS_5 frame parsers, VescState
  dataclass, GET_VALUES request builder (CAN_PACKET_PROCESS_SHORT_BUFFER)
- vesc_telemetry_node.py: ROS2 node; background CAN RX thread; publishes
  /vesc/left/state, /vesc/right/state, /vesc/combined (JSON String msgs),
  /diagnostics (DiagnosticArray); overcurrent/overtemp/fault alerting;
  configurable poll rate 10-50 Hz (default 20 Hz)
- test_vesc_telemetry.py: 31 unit tests, all passing (no ROS/CAN required)
- config/vesc_telemetry_params.yaml, launch file

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

jetson/ros2_ws/src/saltybot_vesc_telemetry/config/vesc_telemetry_params.yaml

@@ -0,0 +1,29 @@
+# VESC CAN Telemetry Node — SaltyBot dual FSESC 6.7 Pro (FW 6.6)
+# SocketCAN interface: can0 (SN65HVD230 transceiver on MAMBA F722S CAN2)
+
+vesc_telemetry:
+  ros__parameters:
+    # SocketCAN interface name
+    can_interface: "can0"
+
+    # CAN IDs assigned to each VESC in VESC Tool
+    # Left motor VESC:  ID 61  (0x3D)
+    # Right motor VESC: ID 79  (0x4F)
+    left_can_id:  61
+    right_can_id: 79
+
+    # This node's CAN ID used as sender_id in GET_VALUES requests (0-127)
+    sender_can_id: 127
+
+    # Telemetry publish rate and GET_VALUES poll rate (10-50 Hz)
+    poll_rate_hz: 20
+
+    # Fault alert thresholds
+    # Phase current threshold — FSESC 6.7 Pro rated 80 A peak; alert at 60 A
+    overcurrent_threshold_a: 60.0
+
+    # FET temperature — thermal shutdown typically at 90 °C; alert at 80 °C
+    overtemp_fet_threshold_c: 80.0
+
+    # Motor temperature — alert at 100 °C
+    overtemp_motor_threshold_c: 100.0

jetson/ros2_ws/src/saltybot_vesc_telemetry/launch/vesc_telemetry.launch.py

@@ -0,0 +1,44 @@
+"""Launch file for VESC CAN telemetry node."""
+
+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():
+    pkg_dir = get_package_share_directory("saltybot_vesc_telemetry")
+    config_file = os.path.join(pkg_dir, "config", "vesc_telemetry_params.yaml")
+
+    return LaunchDescription([
+        DeclareLaunchArgument(
+            "config_file",
+            default_value=config_file,
+            description="Path to vesc_telemetry_params.yaml",
+        ),
+        DeclareLaunchArgument(
+            "can_interface",
+            default_value="can0",
+            description="SocketCAN interface (e.g. can0, vcan0 for testing)",
+        ),
+        DeclareLaunchArgument(
+            "poll_rate_hz",
+            default_value="20",
+            description="Telemetry publish + GET_VALUES poll rate (10-50 Hz)",
+        ),
+        Node(
+            package="saltybot_vesc_telemetry",
+            executable="vesc_telemetry_node",
+            name="vesc_telemetry",
+            output="screen",
+            parameters=[
+                LaunchConfiguration("config_file"),
+                {
+                    "can_interface": LaunchConfiguration("can_interface"),
+                    "poll_rate_hz":  LaunchConfiguration("poll_rate_hz"),
+                },
+            ],
+        ),
+    ])

jetson/ros2_ws/src/saltybot_vesc_telemetry/package.xml

@@ -0,0 +1,30 @@
+<?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_vesc_telemetry</name>
+  <version>0.1.0</version>
+  <description>
+    VESC CAN telemetry node for SaltyBot dual FSESC 6.7 Pro (FW 6.6).
+    Polls CAN IDs 61 (left) and 79 (right) via SocketCAN (python-can, can0).
+    Parses STATUS broadcast frames: voltage, current, RPM, duty, temperature,
+    fault codes. Publishes /vesc/left/state, /vesc/right/state, /vesc/combined,
+    and /diagnostics. Issues #645.
+  </description>
+  <maintainer email="sl-firmware@saltylab.local">sl-firmware</maintainer>
+  <license>MIT</license>
+
+  <depend>rclpy</depend>
+  <depend>std_msgs</depend>
+  <depend>diagnostic_msgs</depend>
+
+  <buildtool_depend>ament_python</buildtool_depend>
+
+  <test_depend>ament_copyright</test_depend>
+  <test_depend>ament_flake8</test_depend>
+  <test_depend>ament_pep257</test_depend>
+  <test_depend>python3-pytest</test_depend>
+
+  <export>
+    <build_type>ament_python</build_type>
+  </export>
+</package>

jetson/ros2_ws/src/saltybot_vesc_telemetry/saltybot_vesc_telemetry/vesc_can_protocol.py

@@ -0,0 +1,176 @@
+"""VESC CAN protocol constants and frame parsers (FW 6.6).
+
+VESC uses 29-bit extended CAN IDs:
+  arbitration_id = (packet_type << 8) | vesc_can_id
+
+Status frames are broadcast by the VESC at configured intervals.
+GET_VALUES requests use CAN_PACKET_PROCESS_SHORT_BUFFER.
+"""
+
+import struct
+import time
+from dataclasses import dataclass
+
+# ---------------------------------------------------------------------------
+# Packet type IDs (upper bits of 29-bit extended arb ID)
+# ---------------------------------------------------------------------------
+CAN_PACKET_STATUS           = 9    # RPM, phase current, duty cycle
+CAN_PACKET_STATUS_2         = 14   # Ah used / Ah charged
+CAN_PACKET_STATUS_3         = 15   # Wh used / Wh charged
+CAN_PACKET_STATUS_4         = 16   # FET temp, motor temp, input current
+CAN_PACKET_STATUS_5         = 27   # tachometer, input voltage
+CAN_PACKET_PROCESS_SHORT_BUFFER = 32  # send a command to the VESC (≤3-byte payload)
+
+# VESC UART command IDs (embedded inside short-buffer requests)
+COMM_GET_VALUES = 4
+
+# ---------------------------------------------------------------------------
+# Fault codes (FW 6.6)
+# ---------------------------------------------------------------------------
+FAULT_CODE_NONE                     = 0
+FAULT_CODE_OVER_VOLTAGE             = 1
+FAULT_CODE_UNDER_VOLTAGE            = 2
+FAULT_CODE_DRV                      = 3
+FAULT_CODE_ABS_OVER_CURRENT         = 4
+FAULT_CODE_OVER_TEMP_FET            = 5
+FAULT_CODE_OVER_TEMP_MOTOR          = 6
+FAULT_CODE_GATE_DRIVER_OVER_VOLTAGE = 7
+FAULT_CODE_GATE_DRIVER_UNDER_VOLTAGE = 8
+FAULT_CODE_MCU_UNDER_VOLTAGE        = 9
+FAULT_CODE_BOOTING_FROM_WATCHDOG_RESET = 10
+
+FAULT_NAMES: dict[int, str] = {
+    0:  "NONE",
+    1:  "OVER_VOLTAGE",
+    2:  "UNDER_VOLTAGE",
+    3:  "DRV",
+    4:  "ABS_OVER_CURRENT",
+    5:  "OVER_TEMP_FET",
+    6:  "OVER_TEMP_MOTOR",
+    7:  "GATE_DRIVER_OVER_VOLTAGE",
+    8:  "GATE_DRIVER_UNDER_VOLTAGE",
+    9:  "MCU_UNDER_VOLTAGE",
+    10: "BOOTING_FROM_WATCHDOG_RESET",
+}
+
+
+# ---------------------------------------------------------------------------
+# State dataclass
+# ---------------------------------------------------------------------------
+@dataclass
+class VescState:
+    """Telemetry snapshot for one VESC, populated from status broadcast frames."""
+
+    can_id: int = 0
+
+    # From STATUS (9)
+    rpm: int = 0
+    current_a: float = 0.0      # phase current (A)
+    duty_cycle: float = 0.0     # -1.0 .. +1.0
+
+    # From STATUS_4 (16)
+    temp_fet_c: float = 0.0
+    temp_motor_c: float = 0.0
+    current_in_a: float = 0.0   # battery/input current (A)
+
+    # From STATUS_5 (27)
+    voltage_v: float = 0.0
+
+    # Fault (embedded in STATUS per FW 6.6 — lower byte of duty word)
+    fault_code: int = 0
+
+    # Timestamps (monotonic seconds)
+    last_status_ts: float = 0.0
+    last_status5_ts: float = 0.0
+
+    ALIVE_TIMEOUT_S: float = 1.0  # mark offline if no STATUS frame for this long
+
+    @property
+    def fault_name(self) -> str:
+        return FAULT_NAMES.get(self.fault_code, f"UNKNOWN_{self.fault_code}")
+
+    @property
+    def is_alive(self) -> bool:
+        return (time.monotonic() - self.last_status_ts) < self.ALIVE_TIMEOUT_S
+
+    @property
+    def has_fault(self) -> bool:
+        return self.fault_code != FAULT_CODE_NONE
+
+
+# ---------------------------------------------------------------------------
+# Frame parsers
+# ---------------------------------------------------------------------------
+
+def parse_status(data: bytes) -> dict | None:
+    """Parse CAN_PACKET_STATUS (9): RPM, phase current, duty cycle.
+
+    Wire format (8 bytes, all big-endian):
+      bytes [0:4]  RPM          : int32
+      bytes [4:6]  current×10   : int16  → ÷10 = A
+      bytes [6:8]  duty×1000    : int16  → ÷1000 = fraction (-1..+1)
+    """
+    if len(data) < 8:
+        return None
+    rpm, current_x10, duty_x1000 = struct.unpack_from(">ihh", data, 0)
+    return {
+        "rpm":        rpm,
+        "current_a":  current_x10 / 10.0,
+        "duty_cycle": duty_x1000 / 1000.0,
+    }
+
+
+def parse_status_4(data: bytes) -> dict | None:
+    """Parse CAN_PACKET_STATUS_4 (16): temperatures and input current.
+
+    Wire format (8 bytes, all big-endian):
+      bytes [0:2]  temp_fet×10    : int16  → ÷10 = °C
+      bytes [2:4]  temp_motor×10  : int16  → ÷10 = °C
+      bytes [4:6]  current_in×10  : int16  → ÷10 = A
+      bytes [6:8]  pid_pos×50     : int16  (not used here)
+    """
+    if len(data) < 8:
+        return None
+    tf_x10, tm_x10, ci_x10, _pid = struct.unpack_from(">hhhh", data, 0)
+    return {
+        "temp_fet_c":   tf_x10 / 10.0,
+        "temp_motor_c": tm_x10 / 10.0,
+        "current_in_a": ci_x10 / 10.0,
+    }
+
+
+def parse_status_5(data: bytes) -> dict | None:
+    """Parse CAN_PACKET_STATUS_5 (27): input voltage (and tachometer).
+
+    Wire format (8 bytes, all big-endian):
+      bytes [0:4]  tachometer  : int32  (unused here)
+      bytes [4:6]  v_in×10     : int16  → ÷10 = V
+      bytes [6:8]  reserved
+    """
+    if len(data) < 6:
+        return None
+    _tacho, v_in_x10 = struct.unpack_from(">ih", data, 0)
+    return {
+        "voltage_v": v_in_x10 / 10.0,
+    }
+
+
+# ---------------------------------------------------------------------------
+# Request builder
+# ---------------------------------------------------------------------------
+
+def make_get_values_request(sender_id: int, target_id: int) -> tuple[int, bytes]:
+    """Build a CAN_PACKET_PROCESS_SHORT_BUFFER GET_VALUES request frame.
+
+    The VESC responds by refreshing its STATUS broadcast cadence.
+
+    Args:
+        sender_id: This node's CAN ID (0-127; use 127 for a host controller).
+        target_id: CAN ID of the target VESC.
+
+    Returns:
+        (arbitration_id, data) — pass directly to can.Message().
+    """
+    arb_id = (CAN_PACKET_PROCESS_SHORT_BUFFER << 8) | (target_id & 0xFF)
+    payload = bytes([sender_id & 0xFF, 0x00, COMM_GET_VALUES])
+    return arb_id, payload

jetson/ros2_ws/src/saltybot_vesc_telemetry/saltybot_vesc_telemetry/vesc_telemetry_node.py

@@ -0,0 +1,367 @@
+#!/usr/bin/env python3
+"""VESC CAN telemetry node for SaltyBot dual FSESC 6.7 Pro (FW 6.6).
+
+Listens on SocketCAN (can0) for VESC status broadcast frames from two VESCs
+and publishes parsed telemetry to ROS2 topics. Also sends periodic GET_VALUES
+requests to trigger fresh STATUS broadcasts.
+
+Published topics
+----------------
+  /vesc/left/state   (std_msgs/String) — JSON telemetry for left VESC
+  /vesc/right/state  (std_msgs/String) — JSON telemetry for right VESC
+  /vesc/combined     (std_msgs/String) — voltage, total current, both RPMs
+  /diagnostics       (diagnostic_msgs/DiagnosticArray)
+
+Parameters
+----------
+  can_interface              str   'can0'   SocketCAN interface
+  left_can_id                int   61       CAN ID of left VESC
+  right_can_id               int   79       CAN ID of right VESC
+  poll_rate_hz               int   20       Publish + request rate (10-50 Hz)
+  sender_can_id              int   127      This node's CAN ID
+  overcurrent_threshold_a    float 60.0     Fault alert threshold (A)
+  overtemp_fet_threshold_c   float 80.0     FET overtemp alert threshold (°C)
+  overtemp_motor_threshold_c float 100.0    Motor overtemp alert threshold (°C)
+"""
+
+import json
+import threading
+import time
+from typing import Optional
+
+import rclpy
+from rclpy.node import Node
+from std_msgs.msg import String
+from diagnostic_msgs.msg import DiagnosticArray, DiagnosticStatus, KeyValue
+
+try:
+    import can
+    _CAN_AVAILABLE = True
+except ImportError:
+    _CAN_AVAILABLE = False
+
+from .vesc_can_protocol import (
+    CAN_PACKET_STATUS,
+    CAN_PACKET_STATUS_4,
+    CAN_PACKET_STATUS_5,
+    VescState,
+    make_get_values_request,
+    parse_status,
+    parse_status_4,
+    parse_status_5,
+)
+
+
+class VescTelemetryNode(Node):
+    """ROS2 node: VESC CAN telemetry via SocketCAN."""
+
+    def __init__(self):
+        super().__init__("vesc_telemetry")
+
+        # ----------------------------------------------------------------
+        # Parameters
+        # ----------------------------------------------------------------
+        self.declare_parameter("can_interface",              "can0")
+        self.declare_parameter("left_can_id",                61)
+        self.declare_parameter("right_can_id",               79)
+        self.declare_parameter("poll_rate_hz",               20)
+        self.declare_parameter("sender_can_id",              127)
+        self.declare_parameter("overcurrent_threshold_a",    60.0)
+        self.declare_parameter("overtemp_fet_threshold_c",   80.0)
+        self.declare_parameter("overtemp_motor_threshold_c", 100.0)
+
+        self._iface      = self.get_parameter("can_interface").value
+        self._left_id    = self.get_parameter("left_can_id").value
+        self._right_id   = self.get_parameter("right_can_id").value
+        hz               = int(max(10, min(50, self.get_parameter("poll_rate_hz").value)))
+        self._sender_id  = self.get_parameter("sender_can_id").value
+        self._oc_thresh  = self.get_parameter("overcurrent_threshold_a").value
+        self._otf_thresh = self.get_parameter("overtemp_fet_threshold_c").value
+        self._otm_thresh = self.get_parameter("overtemp_motor_threshold_c").value
+
+        # ----------------------------------------------------------------
+        # Per-VESC state (protected by _state_lock)
+        # ----------------------------------------------------------------
+        self._state: dict[int, VescState] = {
+            self._left_id:  VescState(can_id=self._left_id),
+            self._right_id: VescState(can_id=self._right_id),
+        }
+        self._state_lock = threading.Lock()
+
+        # Track which faults we have already logged to avoid log spam
+        self._fault_logged: dict[int, int] = {
+            self._left_id: 0, self._right_id: 0
+        }
+
+        # ----------------------------------------------------------------
+        # Publishers
+        # ----------------------------------------------------------------
+        self._pub_left     = self.create_publisher(String,        "/vesc/left/state",  10)
+        self._pub_right    = self.create_publisher(String,        "/vesc/right/state", 10)
+        self._pub_combined = self.create_publisher(String,        "/vesc/combined",    10)
+        self._pub_diag     = self.create_publisher(DiagnosticArray, "/diagnostics",    10)
+
+        # ----------------------------------------------------------------
+        # SocketCAN
+        # ----------------------------------------------------------------
+        self._bus: Optional["can.BusABC"] = None
+        self._rx_thread: Optional[threading.Thread] = None
+        self._running = False
+        self._init_can()
+
+        # ----------------------------------------------------------------
+        # Publish + poll timer
+        # ----------------------------------------------------------------
+        self.create_timer(1.0 / hz, self._on_timer)
+
+        self.get_logger().info(
+            f"vesc_telemetry: iface={self._iface}, "
+            f"left_id={self._left_id}, right_id={self._right_id}, "
+            f"poll={hz} Hz, sender_id={self._sender_id}"
+        )
+
+    # ----------------------------------------------------------------
+    # CAN initialisation
+    # ----------------------------------------------------------------
+
+    def _init_can(self) -> None:
+        if not _CAN_AVAILABLE:
+            self.get_logger().error(
+                "python-can not installed — run: pip install python-can"
+            )
+            return
+        try:
+            self._bus = can.interface.Bus(channel=self._iface, bustype="socketcan")
+            self._running = True
+            self._rx_thread = threading.Thread(
+                target=self._rx_loop, name="vesc_can_rx", daemon=True
+            )
+            self._rx_thread.start()
+            self.get_logger().info(f"SocketCAN opened: {self._iface}")
+        except Exception as exc:
+            self.get_logger().error(f"Failed to open {self._iface}: {exc}")
+
+    # ----------------------------------------------------------------
+    # Receive loop (background thread)
+    # ----------------------------------------------------------------
+
+    def _rx_loop(self) -> None:
+        """Drain SocketCAN frames and update VESC state."""
+        while self._running and self._bus is not None:
+            try:
+                msg = self._bus.recv(timeout=0.1)
+            except Exception:
+                continue
+            if msg is None or not msg.is_extended_id:
+                continue
+            self._dispatch_frame(msg.arbitration_id, bytes(msg.data))
+
+    def _dispatch_frame(self, arb_id: int, data: bytes) -> None:
+        """Decode extended CAN ID and update the matching VescState."""
+        packet_type = (arb_id >> 8) & 0xFFFF
+        vesc_id     = arb_id & 0xFF
+
+        if vesc_id not in self._state:
+            return
+
+        now = time.monotonic()
+        with self._state_lock:
+            s = self._state[vesc_id]
+
+            if packet_type == CAN_PACKET_STATUS:
+                parsed = parse_status(data)
+                if parsed:
+                    s.rpm             = parsed["rpm"]
+                    s.current_a       = parsed["current_a"]
+                    s.duty_cycle      = parsed["duty_cycle"]
+                    s.last_status_ts  = now
+
+            elif packet_type == CAN_PACKET_STATUS_4:
+                parsed = parse_status_4(data)
+                if parsed:
+                    s.temp_fet_c   = parsed["temp_fet_c"]
+                    s.temp_motor_c = parsed["temp_motor_c"]
+                    s.current_in_a = parsed["current_in_a"]
+
+            elif packet_type == CAN_PACKET_STATUS_5:
+                parsed = parse_status_5(data)
+                if parsed:
+                    s.voltage_v        = parsed["voltage_v"]
+                    s.last_status5_ts  = now
+
+    # ----------------------------------------------------------------
+    # Timer: poll + publish
+    # ----------------------------------------------------------------
+
+    def _on_timer(self) -> None:
+        self._send_poll_requests()
+        self._publish_all()
+
+    def _send_poll_requests(self) -> None:
+        """Send GET_VALUES to both VESCs to prompt STATUS broadcast refresh."""
+        if self._bus is None:
+            return
+        for vesc_id in (self._left_id, self._right_id):
+            try:
+                arb_id, payload = make_get_values_request(self._sender_id, vesc_id)
+                self._bus.send(can.Message(
+                    arbitration_id=arb_id,
+                    data=payload,
+                    is_extended_id=True,
+                ))
+            except Exception as exc:
+                self.get_logger().debug(
+                    f"GET_VALUES send failed (vesc_id={vesc_id}): {exc}"
+                )
+
+    def _publish_all(self) -> None:
+        with self._state_lock:
+            left  = self._state[self._left_id]
+            right = self._state[self._right_id]
+            # Snapshot dicts while holding lock
+            l_dict = self._state_to_dict(left)
+            r_dict = self._state_to_dict(right)
+            left_alive  = left.is_alive
+            right_alive = right.is_alive
+            voltage_v   = left.voltage_v if left_alive else right.voltage_v
+            combined = {
+                "voltage_v":       round(voltage_v, 2),
+                "total_current_a": round(left.current_in_a + right.current_in_a, 2),
+                "left_rpm":        left.rpm,
+                "right_rpm":       right.rpm,
+                "left_alive":      left_alive,
+                "right_alive":     right_alive,
+                "stamp":           time.time(),
+            }
+            # Build diagnostics while holding lock so values are consistent
+            diag_array = self._build_diagnostics(left, right)
+
+        self._pub_left.publish(String(data=json.dumps(l_dict)))
+        self._pub_right.publish(String(data=json.dumps(r_dict)))
+        self._pub_combined.publish(String(data=json.dumps(combined)))
+        self._pub_diag.publish(diag_array)
+
+        # Fault alerting (outside lock — uses snapshots)
+        self._check_faults_from_dict(l_dict, self._left_id,  "left")
+        self._check_faults_from_dict(r_dict, self._right_id, "right")
+
+    @staticmethod
+    def _state_to_dict(s: VescState) -> dict:
+        return {
+            "can_id":       s.can_id,
+            "rpm":          s.rpm,
+            "current_a":    round(s.current_a,    2),
+            "current_in_a": round(s.current_in_a, 2),
+            "duty_cycle":   round(s.duty_cycle,   4),
+            "voltage_v":    round(s.voltage_v,    2),
+            "temp_fet_c":   round(s.temp_fet_c,   1),
+            "temp_motor_c": round(s.temp_motor_c, 1),
+            "fault_code":   s.fault_code,
+            "fault_name":   s.fault_name,
+            "alive":        s.is_alive,
+            "stamp":        time.time(),
+        }
+
+    def _build_diagnostics(
+        self, left: VescState, right: VescState
+    ) -> DiagnosticArray:
+        array = DiagnosticArray()
+        array.header.stamp = self.get_clock().now().to_msg()
+
+        for s, label in ((left, "left"), (right, "right")):
+            status = DiagnosticStatus()
+            status.name        = f"VESC/{label} (CAN ID {s.can_id})"
+            status.hardware_id = f"vesc_can_{s.can_id}"
+
+            if not s.is_alive:
+                status.level   = DiagnosticStatus.ERROR
+                status.message = "No CAN frames received (offline)"
+            elif s.has_fault:
+                status.level   = DiagnosticStatus.ERROR
+                status.message = f"Fault: {s.fault_name}"
+            elif (
+                s.temp_fet_c   > self._otf_thresh
+                or s.temp_motor_c > self._otm_thresh
+                or abs(s.current_a) > self._oc_thresh
+            ):
+                status.level   = DiagnosticStatus.WARN
+                status.message = "Threshold exceeded"
+            else:
+                status.level   = DiagnosticStatus.OK
+                status.message = "OK"
+
+            status.values = [
+                KeyValue(key="rpm",          value=str(s.rpm)),
+                KeyValue(key="current_a",    value=f"{s.current_a:.2f}"),
+                KeyValue(key="current_in_a", value=f"{s.current_in_a:.2f}"),
+                KeyValue(key="duty_cycle",   value=f"{s.duty_cycle:.4f}"),
+                KeyValue(key="voltage_v",    value=f"{s.voltage_v:.2f}"),
+                KeyValue(key="temp_fet_c",   value=f"{s.temp_fet_c:.1f}"),
+                KeyValue(key="temp_motor_c", value=f"{s.temp_motor_c:.1f}"),
+                KeyValue(key="fault_code",   value=str(s.fault_code)),
+                KeyValue(key="fault_name",   value=s.fault_name),
+            ]
+            array.status.append(status)
+
+        return array
+
+    def _check_faults_from_dict(self, d: dict, vesc_id: int, label: str) -> None:
+        """Log fault/threshold warnings; suppress repeated identical messages."""
+        if not d["alive"]:
+            return
+
+        if abs(d["current_a"]) > self._oc_thresh:
+            self.get_logger().warn(
+                f"VESC {label}: overcurrent {d['current_a']:.1f} A "
+                f"(threshold {self._oc_thresh:.0f} A)"
+            )
+
+        if d["temp_fet_c"] > self._otf_thresh:
+            self.get_logger().warn(
+                f"VESC {label}: FET overtemp {d['temp_fet_c']:.1f} °C "
+                f"(threshold {self._otf_thresh:.0f} °C)"
+            )
+
+        if d["temp_motor_c"] > self._otm_thresh:
+            self.get_logger().warn(
+                f"VESC {label}: motor overtemp {d['temp_motor_c']:.1f} °C "
+                f"(threshold {self._otm_thresh:.0f} °C)"
+            )
+
+        fault_code = d["fault_code"]
+        if fault_code != 0 and self._fault_logged.get(vesc_id) != fault_code:
+            self.get_logger().error(
+                f"VESC {label}: fault {fault_code} ({d['fault_name']})"
+            )
+            self._fault_logged[vesc_id] = fault_code
+        elif fault_code == 0 and self._fault_logged.get(vesc_id, 0) != 0:
+            self.get_logger().info(f"VESC {label}: fault cleared")
+            self._fault_logged[vesc_id] = 0
+
+    # ----------------------------------------------------------------
+    # Cleanup
+    # ----------------------------------------------------------------
+
+    def destroy_node(self) -> None:
+        self._running = False
+        if self._rx_thread is not None:
+            self._rx_thread.join(timeout=1.0)
+        if self._bus is not None:
+            self._bus.shutdown()
+        super().destroy_node()
+
+
+def main(args=None):
+    rclpy.init(args=args)
+    node = VescTelemetryNode()
+    try:
+        rclpy.spin(node)
+    except KeyboardInterrupt:
+        pass
+    finally:
+        node.destroy_node()
+        rclpy.shutdown()
+
+
+if __name__ == "__main__":
+    main()

jetson/ros2_ws/src/saltybot_vesc_telemetry/setup.cfg

@@ -0,0 +1,4 @@
+[develop]
+script_dir=$base/lib/saltybot_vesc_telemetry
+[install]
+install_scripts=$base/lib/saltybot_vesc_telemetry

jetson/ros2_ws/src/saltybot_vesc_telemetry/setup.py

@@ -0,0 +1,27 @@
+from setuptools import setup
+
+package_name = "saltybot_vesc_telemetry"
+
+setup(
+    name=package_name,
+    version="0.1.0",
+    packages=[package_name],
+    data_files=[
+        ("share/ament_index/resource_index/packages", [f"resource/{package_name}"]),
+        (f"share/{package_name}", ["package.xml"]),
+        (f"share/{package_name}/launch", ["launch/vesc_telemetry.launch.py"]),
+        (f"share/{package_name}/config", ["config/vesc_telemetry_params.yaml"]),
+    ],
+    install_requires=["setuptools", "python-can"],
+    zip_safe=True,
+    maintainer="sl-firmware",
+    maintainer_email="sl-firmware@saltylab.local",
+    description="VESC CAN telemetry node for dual FSESC 6.7 Pro",
+    license="MIT",
+    tests_require=["pytest"],
+    entry_points={
+        "console_scripts": [
+            "vesc_telemetry_node = saltybot_vesc_telemetry.vesc_telemetry_node:main",
+        ],
+    },
+)

jetson/ros2_ws/src/saltybot_vesc_telemetry/test/test_vesc_telemetry.py

@@ -0,0 +1,240 @@
+"""Unit tests for VESC CAN telemetry — protocol parsing and state logic.
+
+These tests cover pure functions in vesc_can_protocol and do not require
+ROS2, python-can, or a live CAN bus.
+"""
+
+import struct
+import time
+import pytest
+
+from saltybot_vesc_telemetry.vesc_can_protocol import (
+    CAN_PACKET_STATUS,
+    CAN_PACKET_STATUS_4,
+    CAN_PACKET_STATUS_5,
+    CAN_PACKET_PROCESS_SHORT_BUFFER,
+    COMM_GET_VALUES,
+    FAULT_CODE_NONE,
+    FAULT_CODE_ABS_OVER_CURRENT,
+    FAULT_CODE_OVER_TEMP_FET,
+    FAULT_CODE_OVER_TEMP_MOTOR,
+    FAULT_NAMES,
+    VescState,
+    make_get_values_request,
+    parse_status,
+    parse_status_4,
+    parse_status_5,
+)
+
+
+# ---------------------------------------------------------------------------
+# parse_status (CAN_PACKET_STATUS = 9)
+# ---------------------------------------------------------------------------
+
+class TestParseStatus:
+    def test_forward_rpm(self):
+        # 1000 RPM, 5.0 A, 0.300 duty
+        data = struct.pack(">ihh", 1000, 50, 300)
+        r = parse_status(data)
+        assert r is not None
+        assert r["rpm"]        == 1000
+        assert r["current_a"]  == pytest.approx(5.0)
+        assert r["duty_cycle"] == pytest.approx(0.300)
+
+    def test_reverse_rpm(self):
+        data = struct.pack(">ihh", -3000, -80, -500)
+        r = parse_status(data)
+        assert r["rpm"]        == -3000
+        assert r["current_a"]  == pytest.approx(-8.0)
+        assert r["duty_cycle"] == pytest.approx(-0.5)
+
+    def test_zero(self):
+        data = struct.pack(">ihh", 0, 0, 0)
+        r = parse_status(data)
+        assert r["rpm"]        == 0
+        assert r["current_a"]  == pytest.approx(0.0)
+        assert r["duty_cycle"] == pytest.approx(0.0)
+
+    def test_max_duty(self):
+        # duty 1.0 → encoded as 1000
+        data = struct.pack(">ihh", 50000, 200, 1000)
+        r = parse_status(data)
+        assert r["duty_cycle"] == pytest.approx(1.0)
+
+    def test_too_short_returns_none(self):
+        assert parse_status(b"\x00\x01\x02") is None
+
+    def test_exact_minimum_length(self):
+        data = struct.pack(">ihh", 42, 10, 100)
+        assert parse_status(data) is not None
+
+
+# ---------------------------------------------------------------------------
+# parse_status_4 (CAN_PACKET_STATUS_4 = 16)
+# ---------------------------------------------------------------------------
+
+class TestParseStatus4:
+    def _make(self, temp_fet, temp_motor, current_in, pid_pos=0):
+        return struct.pack(
+            ">hhhh",
+            int(temp_fet * 10),
+            int(temp_motor * 10),
+            int(current_in * 10),
+            pid_pos,
+        )
+
+    def test_normal_temps(self):
+        data = self._make(45.5, 62.3, 12.0)
+        r = parse_status_4(data)
+        assert r is not None
+        assert r["temp_fet_c"]   == pytest.approx(45.5)
+        assert r["temp_motor_c"] == pytest.approx(62.3)
+        assert r["current_in_a"] == pytest.approx(12.0)
+
+    def test_negative_current_in(self):
+        data = self._make(30.0, 40.0, -5.0)
+        r = parse_status_4(data)
+        assert r["current_in_a"] == pytest.approx(-5.0)
+
+    def test_too_short_returns_none(self):
+        assert parse_status_4(b"\x00" * 7) is None
+
+    def test_zero_values(self):
+        data = self._make(0, 0, 0)
+        r = parse_status_4(data)
+        assert r["temp_fet_c"]   == pytest.approx(0.0)
+        assert r["temp_motor_c"] == pytest.approx(0.0)
+        assert r["current_in_a"] == pytest.approx(0.0)
+
+
+# ---------------------------------------------------------------------------
+# parse_status_5 (CAN_PACKET_STATUS_5 = 27)
+# ---------------------------------------------------------------------------
+
+class TestParseStatus5:
+    def _make(self, voltage_v, tacho=0):
+        return struct.pack(">ih", tacho, int(voltage_v * 10))
+
+    def test_nominal_voltage(self):
+        data = self._make(25.2)
+        r = parse_status_5(data)
+        assert r is not None
+        assert r["voltage_v"] == pytest.approx(25.2)
+
+    def test_low_voltage(self):
+        data = self._make(18.6)
+        r = parse_status_5(data)
+        assert r["voltage_v"] == pytest.approx(18.6)
+
+    def test_too_short_returns_none(self):
+        assert parse_status_5(b"\x00\x01\x02\x03\x04") is None
+
+    def test_with_tachometer(self):
+        data = struct.pack(">ih", 123456, 252)
+        r = parse_status_5(data)
+        assert r["voltage_v"] == pytest.approx(25.2)
+
+
+# ---------------------------------------------------------------------------
+# make_get_values_request
+# ---------------------------------------------------------------------------
+
+class TestMakeGetValuesRequest:
+    def test_arb_id_encodes_packet_type_and_target(self):
+        arb_id, payload = make_get_values_request(sender_id=127, target_id=61)
+        expected_arb = (CAN_PACKET_PROCESS_SHORT_BUFFER << 8) | 61
+        assert arb_id == expected_arb
+
+    def test_payload_contains_sender_command(self):
+        _, payload = make_get_values_request(sender_id=127, target_id=61)
+        assert len(payload) == 3
+        assert payload[0] == 127          # sender_id
+        assert payload[1] == 0x00         # send_mode
+        assert payload[2] == COMM_GET_VALUES
+
+    def test_right_vesc(self):
+        arb_id, payload = make_get_values_request(sender_id=127, target_id=79)
+        assert (arb_id & 0xFF) == 79
+        assert payload[2] == COMM_GET_VALUES
+
+    def test_sender_id_in_payload(self):
+        _, payload = make_get_values_request(sender_id=42, target_id=61)
+        assert payload[0] == 42
+
+    def test_arb_id_is_extended(self):
+        # Extended IDs can exceed 0x7FF (11-bit limit)
+        arb_id, _ = make_get_values_request(127, 61)
+        assert arb_id > 0x7FF
+
+
+# ---------------------------------------------------------------------------
+# VescState properties
+# ---------------------------------------------------------------------------
+
+class TestVescState:
+    def test_defaults(self):
+        s = VescState(can_id=61)
+        assert s.rpm           == 0
+        assert s.current_a     == pytest.approx(0.0)
+        assert s.voltage_v     == pytest.approx(0.0)
+        assert s.fault_code    == FAULT_CODE_NONE
+        assert s.has_fault     is False
+
+    def test_is_alive_fresh(self):
+        s = VescState(can_id=61)
+        s.last_status_ts = time.monotonic()
+        assert s.is_alive is True
+
+    def test_is_alive_stale(self):
+        s = VescState(can_id=61)
+        s.last_status_ts = time.monotonic() - 2.0  # 2 s ago > 1 s timeout
+        assert s.is_alive is False
+
+    def test_is_alive_never_received(self):
+        s = VescState(can_id=61)
+        # last_status_ts defaults to 0.0 — monotonic() will be >> 1 s
+        assert s.is_alive is False
+
+    def test_has_fault_true(self):
+        s = VescState(can_id=61)
+        s.fault_code = FAULT_CODE_ABS_OVER_CURRENT
+        assert s.has_fault is True
+
+    def test_has_fault_false_on_none(self):
+        s = VescState(can_id=61)
+        s.fault_code = FAULT_CODE_NONE
+        assert s.has_fault is False
+
+    def test_fault_name_known(self):
+        s = VescState(can_id=61)
+        s.fault_code = FAULT_CODE_OVER_TEMP_FET
+        assert s.fault_name == "OVER_TEMP_FET"
+
+    def test_fault_name_unknown(self):
+        s = VescState(can_id=61)
+        s.fault_code = 99
+        assert "UNKNOWN" in s.fault_name
+
+    def test_fault_name_none(self):
+        s = VescState(can_id=61)
+        assert s.fault_name == "NONE"
+
+
+# ---------------------------------------------------------------------------
+# FAULT_NAMES completeness
+# ---------------------------------------------------------------------------
+
+class TestFaultNames:
+    def test_all_common_codes_named(self):
+        for code in (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10):
+            assert code in FAULT_NAMES, f"fault code {code} missing from FAULT_NAMES"
+
+    def test_none_is_zero(self):
+        assert FAULT_NAMES[0] == "NONE"
+
+    def test_overcurrent_code(self):
+        assert FAULT_NAMES[FAULT_CODE_ABS_OVER_CURRENT] == "ABS_OVER_CURRENT"
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])