clearpilot/CLAUDE.md

ClearPilot — CLAUDE.md

Project Overview

ClearPilot is a custom fork of FrogPilot (itself a fork of comma.ai's openpilot), based on a 2024 release. It is purpose-built for Brian Hanson's Hyundai Tucson (HDA2 equipped). The vehicle's HDA2 system has specific quirks around how it synchronizes driving state with openpilot that require careful handling.

Key Customizations in This Fork

• UI changes to the onroad driving interface
• Lane change behavior: brief disengage when turn signal is active during lane changes
• Lateral control disabled: the car's own radar cruise control handles lateral; openpilot handles longitudinal only
• Driver monitoring timeouts: modified safety timeouts for the driver monitoring system
• Custom driving models: duck-amigo.thneed, farmville.onnx, wd-40.thneed in selfdrive/clearpilot/models/
• ClearPilot service: Node.js service at selfdrive/clearpilot/ with behavior scripts for lane change and longitudinal control
• Native dashcamd: C++ process capturing raw camera frames via VisionIPC with OMX H.264 hardware encoding
• Standstill power saving: model inference throttled to 1fps and fan quieted when car is stopped
• ClearPilot menu: sidebar settings panel replacing stock home screen (Home, Dashcam, Debug panels)
• Status window: live system stats (temp, fan, storage, RAM, WiFi, VPN, GPS, telemetry status)
• Debug button (LFA): steering wheel button repurposed for screen toggle and future UI actions
• Telemetry system: diff-based CSV logger via ZMQ IPC, toggleable from Debug panel
• Bench mode: --bench flag for onroad UI testing without car connected
• GPS: custom AT-command based GPS daemon (system/clearpilot/gpsd.py) replacing broken qcomgpsd diag interface
• OpenVPN tunnel: auto-connecting VPN to expose device on remote network for SSH access

See GOALS.md for feature roadmap.

Working Rules

CRITICAL: Change Control

This is self-driving software. All changes must be deliberate and well-understood.

• NEVER make changes outside of what is explicitly requested
• Always explain proposed changes first — describe the change, the logic, and the architecture; let Brian review and approve before writing any code
• Brian is an expert on this software — do not override his judgment or assume responsibility for changes he doesn't understand
• Every line must be understood — work slowly and deliberately
• Test everything thoroughly — Brian must always be in the loop
• Do not refactor, clean up, or "improve" code beyond the specific request

File Ownership

We operate as root on this device, but openpilot runs as the comma user (uid=1000, gid=1000). After any code changes that touch multiple files or before testing:

chown -R comma:comma /data/openpilot

Git

• Remote: git@git.internal.hanson.xyz:brianhansonxyz/comma.git
• Branch: clearpilot
• Large model files are tracked in git (intentional — this is a backup)

Samba Share

• Share name: openpilot (e.g. \\comma-3889765b\openpilot)
• Path: /data/openpilot
• Username: comma
• Password: i-like-to-drive-cars
• Runs as comma:comma via force user/group — files created over SMB are owned correctly
• Enabled at boot (smbd + nmbd)

Testing Changes

Always use build_only.sh to compile, then start the manager separately. Never compile individual targets with scons directly — always use the full build script. Always use full paths with su - comma — the login shell drops into /home/comma (volatile tmpfs), not /data/openpilot. Always start the manager after a successful build — don't wait for the user to ask.

# 1. Fix ownership (we edit as root, openpilot runs as comma)
chown -R comma:comma /data/openpilot

# 2. Build (kills running manager, removes prebuilt, compiles, exits)
#    Shows progress spinner on screen. On failure, shows error on screen
#    and prints to stderr. Does NOT start the manager.
su - comma -c "bash /data/openpilot/build_only.sh"

# 3. If build succeeded ($? == 0), start openpilot
su - comma -c "bash /data/openpilot/launch_openpilot.sh"

# 4. Review the aggregate session log for errors
cat /data/log2/current/session.log

# 5. Check per-process stdout/stderr logs if needed
ls /data/log2/current/
cat /data/log2/current/gpsd.log

Adding New Params

The params system uses a C++ whitelist. Adding a new param name in manager.py alone will crash with UnknownKeyName. You must:

1. Register the key in common/params.cc (alphabetically, with PERSISTENT or CLEAR_ON_* flag)
2. Add the default value in selfdrive/manager/manager.py in manager_init()
3. Remove prebuilt, common/params.o, and common/libcommon.a to force rebuild

Memory Params (paramsMemory)

ClearPilot uses memory params (/dev/shm/params/d/) for UI toggles that should reset on boot. Key rules:

• Registration: Register the key in common/params.cc as PERSISTENT (same as FrogPilot pattern — the registration flag does NOT control which path the param lives at)
• C++ access: Use Params{"/dev/shm/params"} — stored as a class member paramsMemory in onroad.h. Do NOT use Params("/dev/shm/params/d") — the Params class appends /d/ internally, so that would resolve to /dev/shm/params/d/d/
• Python access: Use Params("/dev/shm/params")
• Defaults: Set in manager_init() via Params("/dev/shm/params").put(key, value)
• UI toggles: Use ToggleControl with manual toggleFlipped lambda that writes via Params("/dev/shm/params"). Do NOT use ParamControl for memory params — it reads/writes persistent params only
• Current memory params: TelemetryEnabled (default "0"), VpnEnabled (default "1"), ModelStandby (default "0"), ScreenDisplayMode
• IMPORTANT — method names differ between C++ and Python: C++ uses camelCase (putBool, getBool, getInt), Python uses snake_case (put_bool, get_bool, get_int). This is a common source of silent failures — the wrong casing compiles/runs but doesn't work.

Building Native (C++) Processes

• SCons is the build system. Static libraries (common, messaging, cereal, visionipc) must be imported as SCons objects, not -l flags
• The --as-needed linker flag can cause link order issues with static libs — disable it in your SConscript if needed
• OMX encoder object (omx_encoder.o) is compiled by the UI build — reference the pre-built .o file rather than recompiling (avoids "two environments" scons error)
• prebuilt is recreated after every successful build — always remove it before rebuilding

Bench Mode (Onroad UI Testing)

Bench mode allows testing the onroad UI without a car connected. It runs a fake vehicle simulator (bench_onroad.py) as a managed process and disables real car processes (pandad, thermald, controlsd, etc.).

Usage

IMPORTANT: Do NOT use echo to write bench params — echo appends a newline which causes param parsing to fail silently (e.g. gear stays in park). Always use the bench_cmd.py tool.

# 1. Build first
chown -R comma:comma /data/openpilot
su - comma -c "bash /data/openpilot/build_only.sh"

# 2. Start in bench mode
su - comma -c "bash /data/openpilot/launch_openpilot.sh --bench"

# 3. Wait for UI to be ready (polls RPC every 1s, up to 20s)
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd wait_ready"

# 4. Control vehicle state
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd gear D"
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd speed 20"
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd speedlimit 45"
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd cruise 55"
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd engaged 1"

# 5. Inspect UI widget tree (RPC call, instant response)
su - comma -c "PYTHONPATH=/data/openpilot python3 -m selfdrive.clearpilot.bench_cmd dump"

Debugging Crashes

The UI has a SIGSEGV/SIGABRT crash handler (selfdrive/ui/main.cc) that prints a stack trace to stderr, captured in the per-process log:

# Check for crash traces (use /data/log2/current which is always the active session)
grep -A 30 "CRASH" /data/log2/current/ui.log

# Resolve addresses to source lines
addr2line -e /data/openpilot/selfdrive/ui/ui -f 0xADDRESS

# bench_cmd dump detects crash loops automatically:
# if UI process uptime < 5s, it reports "likely crash looping"

# Check per-process logs
ls /data/log2/current/
cat /data/log2/current/session.log
cat /data/log2/current/gpsd.log

UI Introspection RPC

The UI process runs a ZMQ REP server at ipc:///tmp/clearpilot_ui_rpc. Send "dump" to get a recursive widget tree showing class name, visibility, geometry, and stacked layout current indices. This is the primary debugging tool for understanding what the UI is displaying.

• bench_cmd dump — queries the RPC and prints the widget tree
• bench_cmd wait_ready — polls the RPC every second until ReadyWindow is visible (up to 10s)
• ui_dump.py — standalone dump tool (same as bench_cmd dump)

Architecture

• launch_openpilot.sh --bench sets BENCH_MODE=1 env var
• manager.py reads BENCH_MODE, blocks real car processes, enables bench_onroad process
• bench_onroad.py publishes fake pandaStates (ignition=true), carState, controlsState — thermald reads the fake pandaStates to determine ignition and publishes deviceState.started=true on its own
• thermald and camerad run normally in bench mode (thermald manages CPU cores needed for camerad)
• Blocked processes in bench mode: pandad, controlsd, radard, plannerd, calibrationd, torqued, paramsd, locationd, sensord, ubloxd, pigeond, dmonitoringmodeld, dmonitoringd, modeld, soundd, loggerd, micd, dashcamd

Key Files

File	Role
selfdrive/clearpilot/bench_onroad.py	Fake vehicle state publisher
selfdrive/clearpilot/bench_cmd.py	Command tool for setting bench params and querying UI
selfdrive/clearpilot/ui_dump.py	Standalone UI widget tree dump
selfdrive/manager/process_config.py	Registers bench_onroad as managed process (enabled=BENCH_MODE)
selfdrive/manager/manager.py	Blocks conflicting processes in bench mode
launch_openpilot.sh	Accepts --bench flag, exports BENCH_MODE env var
selfdrive/ui/qt/window.cc	UI RPC server (ipc:///tmp/clearpilot_ui_rpc), widget tree dump

Resolved Issues

• SIGSEGV in onroad view (fixed): update_model() in ui.cc dereferenced empty model position data when modeld wasn't running. Fixed by guarding against empty plan_position.getX(). The root cause was found using the crash handler + addr2line.
• showDriverView overriding transitions (fixed): was forcing slayout to onroad/home every frame at 20Hz, overriding park/drive logic. Fixed to only act when not in started state.
• Sidebar appearing during onroad transition (fixed): MainWindow::closeSettings() was re-enabling the sidebar. Fixed by not calling closeSettings during offroadTransition.

Session Logging

Per-process stderr and an aggregate event log are captured in /data/log2/current/.

Log Directory

• /data/log2/current/ is always the active session directory
• init_log_dir() is called once from manager_init() — creates a fresh /data/log2/current/ real directory
• If a previous current/ real directory exists (unresolved session), it's renamed using its mtime timestamp
• If a previous current symlink exists, it's removed
• Once system time is valid (GPS/NTP), the real directory is renamed to /data/log2/YYYY-MM-DD-HH-MM-SS/ and current becomes a symlink to it
• LogDirInitialized param: "0" until time resolves, then "1"
• Open file handles survive the rename (same inode, same filesystem)
• Session directories older than 30 days are deleted on manager startup

Per-Process Logs

• Every PythonProcess and NativeProcess has stderr redirected to {name}.log in the session directory
• DaemonProcess (athenad) redirects both stdout+stderr (existing behavior)
• Stderr is redirected via os.dup2 inside the forked child process

Aggregate Session Log (session.log)

A single session.log in each session directory records major events:

• Manager start/stop/crash
• Process starts, deaths (with exit codes), watchdog restarts
• Onroad/offroad transitions

Key Files

File	Role
selfdrive/manager/process.py	Log directory creation, stderr redirection, session_log logger
selfdrive/manager/manager.py	Log rotation cleanup, session event logging
build_only.sh	Build-only script (no manager start)

Dashcam (dashcamd)

Architecture

dashcamd is a native C++ process that captures raw camera frames directly from camerad via VisionIPC and encodes to MP4 using the Qualcomm OMX H.264 hardware encoder. This replaces the earlier FrogPilot screen recorder approach (QWidget::grab() -> OMX).

• Codec: H.264 AVC (hardware accelerated via OMX.qcom.video.encoder.avc)
• Resolution: 1928x1208 (full camera resolution, no downscaling)
• Bitrate: 2500 kbps
• Container: MP4 (remuxed via libavformat) + SRT subtitle sidecar
• Segment length: 3 minutes per file
• Save path: /data/media/0/videos/YYYYMMDD-HHMMSS/YYYYMMDD-HHMMSS.mp4 (trip directories)
• GPS subtitles: companion .srt file per segment with 1Hz entries (speed MPH, lat/lon, UTC timestamp)
• Trip lifecycle: starts recording on launch with 10-min idle timer; car in drive cancels timer; park/off restarts timer; ignition cycle = new trip
• Graceful shutdown: thermald sets DashcamShutdown param, dashcamd closes segment and acks within 15s
• Storage: ~56 MB per 3-minute segment at 2500 kbps
• Storage device: WDC SDINDDH4-128G UFS 2.1 — automotive grade, ~384 TB write endurance, no concern for continuous writes

Key Differences from Old Screen Recorder

	Old (screen recorder)	New (dashcamd)
Source	QWidget::grab() screen capture	Raw NV12 from VisionIPC
Resolution	1440x720	1928x1208
Works with screen off	No (needs visible widget)	Yes (independent of UI)
Process type	Part of UI process	Standalone native process
Encoder input	RGBA -> NV12 conversion	NV12 direct (added encode_frame_nv12)

Key Files

File	Role
selfdrive/clearpilot/dashcamd.cc	Main dashcam process — VisionIPC -> OMX encoder
selfdrive/clearpilot/SConscript	Build config for dashcamd
selfdrive/frogpilot/screenrecorder/omx_encoder.cc	OMX encoder (added encode_frame_nv12 method)
selfdrive/frogpilot/screenrecorder/omx_encoder.h	Encoder header
selfdrive/manager/process_config.py	dashcamd registered as NativeProcess, camerad always_run, encoderd disabled
system/loggerd/deleter.py	Trip-aware storage rotation (oldest trip first, then segments within active trip)

Params

• DashcamDebug — when "1", dashcamd runs even without car connected (for bench testing)
• DashcamShutdown — set by thermald before power-off, dashcamd acks by clearing it

Standstill Power Saving

When carState.standstill is true:

• modeld: skips GPU inference on 19/20 frames (1fps vs 20fps), reports 0 frame drops to avoid triggering modeldLagging in controlsd
• dmonitoringmodeld: same 1fps throttle, added carState subscription
• Fan controller: uses offroad clamps (0-30%) instead of onroad (30-100%) at standstill; thermal protection still active via feedforward if temp > 60°C

Key Files

File	Role
selfdrive/modeld/modeld.py	Standstill frame skip logic
selfdrive/modeld/dmonitoringmodeld.py	Standstill frame skip logic
selfdrive/thermald/fan_controller.py	Standstill-aware fan clamps
selfdrive/thermald/thermald.py	Passes standstill to fan controller via carState

Display Modes (LFA/LKAS Debug Button)

The Hyundai Tucson's LFA steering wheel button cycles through 5 display modes via ScreenDisplayMode param (/dev/shm/params, CLEAR_ON_MANAGER_START, default 0).

Display States

State	Name	Display	Camera	Path Drawing
0	auto-normal	on	yes	filled (normal)
1	auto-nightrider	on	black	2px outline only
2	normal (manual)	on	yes	filled (normal)
3	screen off	GPIO off	n/a	n/a
4	nightrider (manual)	on	black	2px outline only

Auto Day/Night Switching

• gpsd.py computes is_daylight(lat, lon, utc_dt) using NOAA solar position algorithm
• First calculation immediately on GPS fix + valid clock, then every 30 seconds
• State 0 + sunset → auto-switch to 1; State 1 + sunrise → auto-switch to 0
• States 2/3/4 are never touched by auto logic
• IsDaylight param written to /dev/shm/params for reference

Button Behavior

Onroad (car in drive gear): 0→4, 1→2, 2→3, 3→4, 4→2 (never back to auto via button)

Not in drive (parked/off): any except 3 → 3 (screen off), state 3 → 0 (auto-normal)

Nightrider Mode

• Camera feed suppressed (OpenGL clears to black instead of rendering camera texture)
• All HUD elements (speed, alerts, telemetry indicator) still visible
• Path/lane polygons drawn as 2px outlines only (no gradient fill)
• Lane lines, road edges, blind spot paths, adjacent paths all use outline rendering

Signal Chain

Steering wheel LFA button press
  -> CAN-FD: cruise_btns_msg_canfd["LFA_BTN"]
  -> Edge detection → ButtonEvent(type=FrogPilotButtonType.lkas)
  -> controlsd.clearpilot_state_control()
     -> Reads ScreenDisplayMode, applies transition table based on driving_gear
     -> Writes new ScreenDisplayMode to /dev/shm/params
  -> UI reads ScreenDisplayMode in paintEvent() (for camera/nightrider)
     and drawHud() (for display power on/off)

Key Files

File	Role
selfdrive/controls/controlsd.py	Button state machine, writes ScreenDisplayMode
selfdrive/ui/qt/onroad.cc	Nightrider rendering, display power control
selfdrive/ui/qt/home.cc	Display power for park/splash state
system/clearpilot/gpsd.py	Sunset/sunrise calc, auto day/night transitions
selfdrive/clearpilot/bench_cmd.py	debugbutton command simulates button press

Screen Timeout / Display Power

Display power is managed by Device::updateWakefulness() in selfdrive/ui/ui.cc.

• Ignition off (offroad): screen blanks after ScreenTimeout seconds (default 120) of no touch. Tapping wakes it.
• Ignition on (onroad): screen stays on unconditionally — ignition=true short-circuits the timeout check.
• Debug button (LFA): cycles through display modes including screen off (state 3). Only state 3 calls Hardware::set_display_power(false).

Offroad UI (ClearPilot Menu)

The offroad home screen (selfdrive/ui/qt/home.cc) is a sidebar settings panel replacing the stock home screen. The original system settings are no longer accessible — the ClearPilot menu is the only settings interface.

Panels

• General: Status window, Reset Calibration, Shutdown Timer, Reboot/Soft Reboot/Power Off
• Network: WiFi management, tethering, roaming, hidden networks (APN settings removed)
• Dashcam: placeholder for future dashcam footage viewer
• Debug: Telemetry logging toggle

Navigation

• Tapping the splash screen (ReadyWindow) opens the ClearPilot menu
• "← Back" button returns to splash or onroad view
• Sidebar with stock metrics (TEMP, VEHICLE, CONNECT) is hidden

Device: comma 3x

Hardware

• Qualcomm Snapdragon SoC (aarch64)
• Serial: comma-3889765b
• Storage: WDC SDINDDH4-128G, 128 GB UFS 2.1
• Connects to the car via comma panda (CAN bus interface)

Operating System

• Ubuntu 20.04.6 LTS (Focal Fossa) on aarch64
• Kernel: 4.9.103+ (custom comma.ai PREEMPT build, Feb 2024) — very old, vendor-patched Qualcomm kernel
• Python: 3.11.4 via pyenv at /usr/local/pyenv/versions/3.11.4/ (system python is 3.8, do not use)
• AGNOS version: 9.7 (comma's custom OS layer on top of Ubuntu)
• Display server: Weston (Wayland compositor) on tty1
• SELinux: mounted (enforcement status varies)

Users

• comma (uid=1000) — the user openpilot runs as; member of root, sudo, disk, gpu, gpio groups
• root — what we SSH in as; files must be chowned back to comma before running openpilot

Filesystem / Mount Quirks

Mount	Device	Type	Notes
/	/dev/sda7	ext4	Root filesystem, read-write
/data	/dev/sda12	ext4	Persistent. Openpilot lives here. Survives reboots.
/home	overlay	overlayfs	VOLATILE — upperdir on tmpfs, changes lost on reboot
/tmp	tmpfs	tmpfs	Volatile, 150 MB
/var	tmpfs	tmpfs	Volatile, 128 MB (fstab) / 1.5 GB (actual)
/systemrw	/dev/sda10	ext4	Writable system overlay, noexec
/persist	/dev/sda2	ext4	Persistent config/certs, noexec
/cache	/dev/sda11	ext4	Android-style cache partition
/dsp	/dev/sde26	ext4	Read-only Qualcomm DSP firmware
/firmware	/dev/sde4	vfat	Read-only firmware blobs

Hardware Encoding

• OMX: OMX.qcom.video.encoder.avc (H.264) and OMX.qcom.video.encoder.hevc — used by dashcamd and screen recorder
• V4L2: Qualcomm VIDC at /dev/v4l/by-path/platform-aa00000.qcom_vidc-video-index1 — used by encoderd (now disabled). Not accessible from ffmpeg due to permission/driver issues
• ffmpeg: v4.2.2, has h264_v4l2m2m and h264_omx listed but neither works from ffmpeg subprocess (OMX port issues, V4L2 device not found). Use OMX directly via the C++ encoder

Fan Control

Software-controlled via thermald -> fan_controller.py -> panda USB -> PWM. Target temp 70°C, PI+feedforward controller. See Standstill Power Saving section for standstill-aware clamps.

Boot Sequence

Power On
  -> systemd: comma.service (runs as comma user)
    -> /usr/comma/comma.sh (waits for Weston, handles factory reset)
      -> /data/continue.sh (exec bridge to openpilot)
        -> /data/openpilot/launch_openpilot.sh
          -> Kills other instances of itself and manager.py
          -> Runs on_start.sh (logo, reverse SSH)
          -> exec launch_chffrplus.sh
            -> Sources launch_env.sh (thread counts, AGNOS_VERSION)
            -> Runs agnos_init (marks boot slot, GPU perms, checks OS update)
            -> Sets PYTHONPATH, symlinks /data/pythonpath
            -> Runs build.py if no `prebuilt` marker
            -> Launches selfdrive/manager/manager.py
              -> manager_init() sets default params
              -> ensure_running() loop starts all managed processes

Openpilot Architecture

Process Manager

selfdrive/manager/manager.py orchestrates all processes defined in selfdrive/manager/process_config.py.

Always-Running Processes (offroad + onroad)

• thermald — thermal management and fan control
• pandad — panda CAN bus interface
• ui — Qt-based onroad/offroad UI
• deleter — storage cleanup (9 GB threshold)
• statsd, timed, logmessaged, tombstoned — telemetry/logging
• manage_athenad — comma cloud connectivity
• fleet_manager, frogpilot_process — FrogPilot additions

Onroad-Only Processes (when driving)

• controlsd — main vehicle control loop
• plannerd — path planning
• radard — radar processing
• modeld — driving model inference (throttled to 1fps at standstill)
• dmonitoringmodeld — driver monitoring model (throttled to 1fps at standstill)
• locationd, calibrationd, paramsd, torqued — localization and calibration
• sensord — IMU/sensor data
• soundd — alert sounds
• camerad — camera capture
• loggerd — CAN/sensor log recording (video encoding disabled)

ClearPilot Processes

• dashcamd — raw camera dashcam recording (runs onroad or with DashcamDebug flag)

GPS

• Device has no u-blox chip (/dev/ttyHS0 does not exist) — ubloxd/pigeond never start
• GPS hardware is a Quectel EC25 LTE modem (USB, lsusb: 2c7c:0125) with built-in GPS
• GPS is accessed via AT commands through mmcli: mmcli -m any --command='AT+QGPSLOC=2'
• qcomgpsd (original openpilot process) uses the modem's diag interface which is broken on this device — the diag recv loop blocks forever after setup. Commented out.
• system/clearpilot/gpsd.py is the replacement — polls GPS via AT commands at 1Hz, publishes gpsLocation cereal messages
• GPS data flows: gpsd → gpsLocation → locationd → liveLocationKalman → timed (sets system clock)
• locationd checks UbloxAvailable param (false on this device) to subscribe to gpsLocation instead of gpsLocationExternal
• mmcli returns response: '...' wrapper — at_cmd() strips it before parsing (fixed)
• GPS antenna power must be enabled via GPIO: gpio_set(GPIO.GNSS_PWR_EN, True)
• System /usr/sbin/gpsd daemon may respawn and interfere — should be disabled or killed

Telemetry

• Client: selfdrive/clearpilot/telemetry.py — tlog(group, data) sends JSON over ZMQ PUSH
• Collector: selfdrive/clearpilot/telemetryd.py — diffs against previous state, writes changed values to CSV
• Toggle: TelemetryEnabled memory param, controlled from Debug panel in ClearPilot menu
• Auto-disable: disabled on every manager start; disabled if /data free < 5GB
• Hyundai CAN-FD data: logged from selfdrive/car/hyundai/carstate.py update_canfd() — groups: car, cruise, speed_limit, buttons
• GPS data: logged directly by telemetryd via cereal gpsLocation subscription at 1Hz — group: gps (latitude, longitude, speed, altitude, bearing, accuracy)
• CSV location: /data/log2/current/telemetry.csv (or session directory)
• Onroad overlay: when telemetry enabled, status bar shows temp, fan %, model FPS, and STANDSTILL indicator
• Speed limit: speed_limit.calculated is the final computed speed limit value (in vehicle units, MPH when is_metric=False). This is the value that will be used for the future speed limit warning chime feature

Key Dependencies

• Python 3.11 (via pyenv) with: numpy, casadi, onnx/onnxruntime, pycapnp, pyzmq, sentry-sdk, sympy, Cython
• capnp (Cap'n Proto) — IPC message serialization between all processes
• ZeroMQ — IPC transport layer
• Qt 5 — UI framework (with WebEngine available but not used for rotation reasons)
• OpenMAX (OMX) — hardware video encoding
• libavformat — MP4 container muxing
• libyuv — color space conversion
• SCons — build system for native C++ components