feat(ui): add a 0-X mode timing a standing start to a target speed

CHANGELOG.md

@@ -8,6 +8,23 @@ The project follows Semantic Versioning once the first firmware release is tagge
 
 ### Added
 
+- a **0-X** mode: the time from a standing start to a target speed, counting up from
+  `0.00`, stopping the instant the target is reached and turning green. Coming back to rest
+  re-arms it; a tap resets it sooner. The target is chosen in `SETUP` -> `0-X TARGET`
+- both ends of a 0-X run are **interpolated rather than quantised**. A stationary receiver
+  reports a few centimetres per second of noise, not zero, so the start is estimated by
+  extrapolating back along the acceleration between the first two moving fixes to where
+  speed would have been zero; the finish is interpolated between the fixes straddling the
+  target. At 25 Hz a fix lands every 40 ms, so without both the second decimal would be
+  decoration. A 0-60 at 4 m/s2 measures 6.71 s against a true 6.7056
+- a 0-X run whose fixes dry up is **abandoned, not finished**. The number stops climbing
+  either way, which is the whole problem: a stalled run looks exactly like an arrival, so
+  it says `LOST FIX` and is never green
+- the settings record is at **version 8**, carrying the 0-X target. Unlike appending a
+  mode, a new field changes a fixed-width record's length, so this needed a migration
+  rather than only a wider validation bound. A v7 device keeps every setting it had and
+  takes the default target, because it never had an opinion about one
+
 - a **Compass** mode: a fixed card with north up, a marker travelling its rim, and the
   bearing in degrees at the centre. The heading was already decoded - `headMot` and
   `headAcc` have been reaching `GnssFix` every epoch - so this needed no parser work at all

Makefile

@@ -48,6 +48,7 @@ GPS_ONLY_TEST_BINARY := build/host/gps_only_test
 CLOCK_TEST_BINARY := build/host/clock_test
 SPEED_ONLY_TEST_BINARY := build/host/speed_only_test
 COMPASS_TEST_BINARY := build/host/compass_test
+ACCELERATION_TEST_BINARY := build/host/acceleration_test
 IMU_CALIBRATION_TEST_BINARY := build/host/imu_calibration_test
 SESSION_URGENCY_TEST_BINARY := build/host/session_urgency_test
 TIME_ROLLER_TEST_BINARY := build/host/time_roller_test
@@ -66,9 +67,9 @@ SIMULATOR_BUILD_DIR ?= build/simulator
 SIMULATOR_IMAGE ?= track-session-timer-simulator:lvgl-9.5.0
 CMAKE ?= cmake
 
-.PHONY: check venv python-env test track-validate uk-track-pack test-track-pack track-pack-test simulator-track-catalog-test simulator-fixture-validate repo-check host-test simulator-model-test session-state-test settings-test settings-editor-test projection-test intersection-test crossing-validation-test crossing-time-test lap-state-machine-test timing-engine-test gate-event-engine-test track-definition-test track-capture-test track-matching-test track-selection-test log-format-test async-logger-test session-review-test diagnostics-test active-session-test display-policy-test imu-meter-test rest-session-test track-catalog-test shell-navigation-test device-mode-test gps-only-test clock-test speed-only-test compass-test imu-calibration-test session-urgency-test time-roller-test session-trigger-test summary-store-test summary-file-test review-cards-test ubx-parser-test fix-validation-test gnss-pipeline-test gnss-configure-test i2c-transport-test gate-capture-test gate-session-automation-test ui-foundation-test navigation-test simulator-configure simulator-build simulator-test simulator-run simulator-container-image simulator-container-test simulator-clean firmware-build firmware-container-build firmware-container-flash firmware-container-monitor firmware-container-flash-monitor firmware-container-erase firmware-capture-boot firmware-device-info firmware-clean issue-preview label-preview
+.PHONY: check venv python-env test track-validate uk-track-pack test-track-pack track-pack-test simulator-track-catalog-test simulator-fixture-validate repo-check host-test simulator-model-test session-state-test settings-test settings-editor-test projection-test intersection-test crossing-validation-test crossing-time-test lap-state-machine-test timing-engine-test gate-event-engine-test track-definition-test track-capture-test track-matching-test track-selection-test log-format-test async-logger-test session-review-test diagnostics-test active-session-test display-policy-test imu-meter-test rest-session-test track-catalog-test shell-navigation-test device-mode-test gps-only-test clock-test speed-only-test compass-test acceleration-test imu-calibration-test session-urgency-test time-roller-test session-trigger-test summary-store-test summary-file-test review-cards-test ubx-parser-test fix-validation-test gnss-pipeline-test gnss-configure-test i2c-transport-test gate-capture-test gate-session-automation-test ui-foundation-test navigation-test simulator-configure simulator-build simulator-test simulator-run simulator-container-image simulator-container-test simulator-clean firmware-build firmware-container-build firmware-container-flash firmware-container-monitor firmware-container-flash-monitor firmware-container-erase firmware-capture-boot firmware-device-info firmware-clean issue-preview label-preview
 
-check: python-env test track-validate test-track-pack track-pack-test simulator-track-catalog-test simulator-fixture-validate repo-check host-test simulator-model-test session-state-test settings-test settings-editor-test projection-test intersection-test crossing-validation-test crossing-time-test lap-state-machine-test timing-engine-test gate-event-engine-test track-definition-test track-capture-test track-matching-test track-selection-test log-format-test async-logger-test session-review-test diagnostics-test active-session-test display-policy-test imu-meter-test rest-session-test track-catalog-test shell-navigation-test device-mode-test gps-only-test clock-test speed-only-test compass-test imu-calibration-test session-urgency-test time-roller-test session-trigger-test summary-store-test summary-file-test review-cards-test ubx-parser-test fix-validation-test gnss-pipeline-test gnss-configure-test i2c-transport-test gate-capture-test gate-session-automation-test ui-foundation-test navigation-test
+check: python-env test track-validate test-track-pack track-pack-test simulator-track-catalog-test simulator-fixture-validate repo-check host-test simulator-model-test session-state-test settings-test settings-editor-test projection-test intersection-test crossing-validation-test crossing-time-test lap-state-machine-test timing-engine-test gate-event-engine-test track-definition-test track-capture-test track-matching-test track-selection-test log-format-test async-logger-test session-review-test diagnostics-test active-session-test display-policy-test imu-meter-test rest-session-test track-catalog-test shell-navigation-test device-mode-test gps-only-test clock-test speed-only-test compass-test acceleration-test imu-calibration-test session-urgency-test time-roller-test session-trigger-test summary-store-test summary-file-test review-cards-test ubx-parser-test fix-validation-test gnss-pipeline-test gnss-configure-test i2c-transport-test gate-capture-test gate-session-automation-test ui-foundation-test navigation-test
 
 venv:
 	python3 -m venv .venv
@@ -586,6 +587,15 @@ imu-calibration-test:
 		tests/cpp/test_imu_calibration.cpp -o $(IMU_CALIBRATION_TEST_BINARY)
 	$(IMU_CALIBRATION_TEST_BINARY)
 
+acceleration-test:
+	mkdir -p build/host
+	$(CXX) -std=c++17 -Wall -Wextra -Werror -pedantic \
+		-Ifirmware/components/domain/include \
+		-Ifirmware/components/ui/include \
+		firmware/components/ui/gps_only.cpp firmware/components/ui/acceleration.cpp \
+		tests/cpp/test_acceleration.cpp -o $(ACCELERATION_TEST_BINARY)
+	$(ACCELERATION_TEST_BINARY)
+
 compass-test:
 	mkdir -p build/host
 	$(CXX) -std=c++17 -Wall -Wextra -Werror -pedantic \

README.md

@@ -34,7 +34,8 @@ device loads them and runs timer-only. #184's test loop is the route to a first
 With nothing attached GPS Only reports "NO RECEIVER", which is the truth rather than a
 fault.
 
-Three modes are built on those fixes. **Compass** shows course over ground on a fixed card,
+Four modes are built on those fixes. **0-X** times a standing start to a target speed,
+interpolating both ends rather than quantising them to the fix rate. **Compass** shows course over ground on a fixed card,
 and hides its marker entirely when the car is too slow for the receiver to know which way it
 is going - a parked vehicle has no heading, and the board has no magnetometer to supply one.
 **Speed Only** shows road speed in mph at 248 px -

docs/SETTINGS.md

@@ -6,13 +6,14 @@ file or NVS operations.
 
 ## Current schema
 
-Version 4 stores:
+Version 8 stores:
 
 - session and rest durations
 - launch sensitivity
 - average lap time and lower-display choice
 - day and night brightness presets
-- operating mode (timer, G-meter, GPS Only, Clock, Speed Only or Compass)
+- operating mode (timer, G-meter, GPS Only, Clock, Speed Only, Compass or 0-X)
+- the 0-X target speed
 - Trackday Mode enable/disable state
 - repeating lap boundary (`START LINE` or `FINISH LINE`)
 - independent Pit Exit Auto-Start and Pit Entry Auto-Stop enable/disable states

firmware/components/settings/component.cpp

@@ -20,7 +20,8 @@ constexpr std::size_t kLegacyV5PayloadSize = 74;
 // v6 appends the session trigger, which nothing before it had.
 // v7 changed what the launch field may hold, not the shape of the payload.
 constexpr std::size_t kLegacyV6PayloadSize = 75;
-constexpr std::size_t kCurrentPayloadSize = 75;
+constexpr std::size_t kLegacyV7PayloadSize = 75;
+constexpr std::size_t kCurrentPayloadSize = 76;
 
 inline constexpr std::uint32_t kMaximumDurationSeconds = 24U * 60U * 60U;
 inline constexpr std::uint32_t kMinimumSessionSeconds = 60U;
@@ -157,6 +158,18 @@ std::uint16_t nearest_launch_sensitivity(const std::uint16_t milli_g) noexcept
     return best;
 }
 
+[[nodiscard]] bool valid_acceleration_target(const std::uint8_t mph) noexcept
+{
+    // One of the offered speeds, not merely a plausible number. A record carrying a target
+    // the picker cannot reach is a record this firmware did not write.
+    for (const auto offered : kAccelerationTargetsMph) {
+        if (offered == mph) {
+            return true;
+        }
+    }
+    return false;
+}
+
 bool valid_settings(const DeviceSettings& settings) noexcept
 {
     return settings.session_duration_seconds >= kMinimumSessionSeconds &&
@@ -166,7 +179,8 @@ bool valid_settings(const DeviceSettings& settings) noexcept
            settings.average_lap_seconds <= 59 * 60 + 59 &&
            valid_brightness(settings.day_brightness_percent) &&
            valid_brightness(settings.night_brightness_percent) &&
-           settings.operating_mode <= OperatingMode::compass &&
+           settings.operating_mode <= OperatingMode::acceleration &&
+           valid_acceleration_target(settings.acceleration_target_mph) &&
            settings.orientation <= OrientationMode::automatic &&
            settings.lower_display <= LowerDisplayMode::laps_remaining &&
            (settings.average_lap_seconds > 0 ||
@@ -271,14 +285,26 @@ SettingsBlob encode_legacy_settings_v6(const DeviceSettings& settings) noexcept
     return make_blob(6, payload.data(), payload.size());
 }
 
-SettingsBlob encode_settings(const DeviceSettings& settings) noexcept
+SettingsBlob encode_legacy_settings_v7(const DeviceSettings& settings) noexcept
 {
     const auto legacy = encode_legacy_settings_v6(settings);
     if (legacy.size == 0) {
         return {};
     }
-    std::array<std::uint8_t, kCurrentPayloadSize> payload{};
+    std::array<std::uint8_t, kLegacyV7PayloadSize> payload{};
     std::copy_n(legacy.bytes.data() + kHeaderSize, kLegacyV6PayloadSize, payload.data());
+    return make_blob(7, payload.data(), payload.size());
+}
+
+SettingsBlob encode_settings(const DeviceSettings& settings) noexcept
+{
+    const auto legacy = encode_legacy_settings_v7(settings);
+    if (legacy.size == 0) {
+        return {};
+    }
+    std::array<std::uint8_t, kCurrentPayloadSize> payload{};
+    std::copy_n(legacy.bytes.data() + kHeaderSize, kLegacyV7PayloadSize, payload.data());
+    payload[75] = settings.acceleration_target_mph;
     return make_blob(kCurrentSettingsVersion, payload.data(), payload.size());
 }
 
@@ -322,7 +348,7 @@ DecodeResult decode_settings(const SettingsBlob& blob, DeviceSettings& settings)
         return DecodeResult::migrated_v1;
     }
     if (version != 2 && version != 3 && version != 4 && version != 5 && version != 6 &&
-        version != kCurrentSettingsVersion) {
+        version != 7 && version != kCurrentSettingsVersion) {
         return DecodeResult::unsupported_version;
     }
     const auto expected_payload_size =
@@ -331,6 +357,7 @@ DecodeResult decode_settings(const SettingsBlob& blob, DeviceSettings& settings)
         : version == 4 ? kLegacyV4PayloadSize
         : version == 5 ? kLegacyV5PayloadSize
         : version == 6 ? kLegacyV6PayloadSize
+        : version == 7 ? kLegacyV7PayloadSize
                        : kCurrentPayloadSize;
     if (payload_size != expected_payload_size) {
         return DecodeResult::corrupt;
@@ -365,10 +392,20 @@ DecodeResult decode_settings(const SettingsBlob& blob, DeviceSettings& settings)
     if (version >= 6) {
         candidate.session_trigger = static_cast<SessionTrigger>(payload[74]);
     }
-    if (version < kCurrentSettingsVersion) {
+    if (version >= 8) {
+        candidate.acceleration_target_mph = payload[75];
+    }
+    // Anything older predates 0-X entirely, so it keeps the default rather than being
+    // treated as a device that chose it. A migrated record is a record that never had an
+    // opinion about this, not one whose opinion was zero.
+    if (version < 7) {
         // Before v7 the ladder ran to 4 g and offered zero as "off". Snapping keeps the
         // rest of the blob rather than failing validation over one field and taking every
         // unrelated setting back to defaults.
+        //
+        // Pinned to 7 rather than to kCurrentSettingsVersion: this corrects a v6-and-older
+        // ladder, and a record written by v7 already has a snapped value. Leaving it as
+        // "older than current" would have silently re-snapped every future version too.
         candidate.launch_sensitivity_milli_g =
             nearest_launch_sensitivity(candidate.launch_sensitivity_milli_g);
     }
@@ -389,6 +426,7 @@ DecodeResult decode_settings(const SettingsBlob& blob, DeviceSettings& settings)
            : version == 4 ? DecodeResult::migrated_v4
            : version == 5 ? DecodeResult::migrated_v5
            : version == 6 ? DecodeResult::migrated_v6
+           : version == 7 ? DecodeResult::migrated_v7
                           : DecodeResult::current;
 }
 
@@ -445,6 +483,9 @@ SettingsLoadReport SettingsManager::load() noexcept
     case DecodeResult::migrated_v6:
         current_ = decoded;
         return {SettingsSource::migrated_v6, persist(current_)};
+    case DecodeResult::migrated_v7:
+        current_ = decoded;
+        return {SettingsSource::migrated_v7, persist(current_)};
     case DecodeResult::corrupt:
         current_ = {};
         return {SettingsSource::defaults_corrupt, persist(current_)};

firmware/components/settings/include/track_timer/settings/settings.hpp

@@ -7,7 +7,7 @@
 
 namespace track_timer::settings {
 
-inline constexpr std::uint16_t kCurrentSettingsVersion = 7;
+inline constexpr std::uint16_t kCurrentSettingsVersion = 8;
 inline constexpr std::size_t kSettingsBlobCapacity = 128;
 inline constexpr std::size_t kTrackIdentifierCapacity = 48;
 
@@ -28,6 +28,8 @@ enum class OperatingMode : std::uint8_t {
     // A compass card from the receiver's course over ground. Appended again: the order of
     // this enum is the stored format, whatever order the modes are offered in.
     compass,
+    // Standing-start acceleration timing, to a target speed chosen in Setup.
+    acceleration,
 };
 
 enum class OrientationMode : std::uint8_t {
@@ -67,6 +69,11 @@ inline constexpr std::array<std::uint16_t, 10> kLaunchSensitivityMilliG{
 // A deliberate pit exit, without tripping on a bump.
 inline constexpr std::uint16_t kDefaultLaunchSensitivityMilliG = 300;
 
+// The speeds a 0-X run can be timed to. Sixty is the one everybody means, which is why it
+// is the default; thirty is reachable in a car park and a hundred is a straight.
+inline constexpr std::array<std::uint8_t, 6> kAccelerationTargetsMph{30, 40, 50, 60, 70, 100};
+inline constexpr std::uint8_t kDefaultAccelerationTargetMph = 60;
+
 // Snaps any stored value onto the ladder. Settings written before v7 hold values that are
 // no longer offered, and rejecting them would fail the whole blob and take every unrelated
 // setting back to defaults with it.
@@ -95,6 +102,11 @@ struct DeviceSettings {
     // sites. Owns pit_exit_auto_start_enabled, which is derived from it rather than
     // edited separately, so the two cannot disagree.
     SessionTrigger session_trigger{SessionTrigger::manual};
+    // The speed a 0-X run is timed to, in mph. Appended, like every field before it - but
+    // unlike appending a mode this is a new byte in a fixed-width record, so it is what
+    // took the format to version 8 and needed a migration path rather than only a wider
+    // validation bound.
+    std::uint8_t acceleration_target_mph{kDefaultAccelerationTargetMph};
 };
 
 struct LegacySettingsV1 {
@@ -131,6 +143,7 @@ enum class DecodeResult : std::uint8_t {
     migrated_v4,
     migrated_v5,
     migrated_v6,
+    migrated_v7,
     corrupt,
     unsupported_version,
 };
@@ -143,6 +156,7 @@ enum class SettingsSource : std::uint8_t {
     migrated_v4,
     migrated_v5,
     migrated_v6,
+    migrated_v7,
     defaults_missing,
     defaults_corrupt,
     defaults_unsupported,
@@ -193,6 +207,8 @@ struct FeatureAvailability {
     const LegacySettingsV1& settings) noexcept;
 [[nodiscard]] SettingsBlob encode_legacy_settings_v2(
     const DeviceSettings& settings) noexcept;
+[[nodiscard]] SettingsBlob encode_legacy_settings_v7(
+    const DeviceSettings& settings) noexcept;
 [[nodiscard]] SettingsBlob encode_legacy_settings_v6(
     const DeviceSettings& settings) noexcept;
 [[nodiscard]] SettingsBlob encode_legacy_settings_v5(

firmware/components/ui/CMakeLists.txt

@@ -1,6 +1,6 @@
 idf_component_register(
     SRCS "component.cpp" "active_session.cpp" "input.cpp" "shell_navigation.cpp" "device_mode.cpp" "value_picker.cpp" "gesture_input.cpp" "carousel_screen.cpp" "clock.cpp" "clock_screen.cpp" "time_roller.cpp" "time_roller_screen.cpp" "trackday_screen.cpp" "timer_font.cpp" "diagnostics.cpp" "diagnostics_screen.cpp"
-         "display_policy.cpp" "foundation.cpp" "gate_capture.cpp" "gate_capture_screen.cpp" "gps_only.cpp" "gps_only_screen.cpp" "speed_only.cpp" "speed_only_screen.cpp" "compass.cpp" "compass_screen.cpp" "g_meter_screen.cpp" "g_radar_screen.cpp" "imu_meter.cpp"
+         "display_policy.cpp" "foundation.cpp" "gate_capture.cpp" "gate_capture_screen.cpp" "gps_only.cpp" "gps_only_screen.cpp" "speed_only.cpp" "speed_only_screen.cpp" "compass.cpp" "compass_screen.cpp" "acceleration.cpp" "acceleration_screen.cpp" "g_meter_screen.cpp" "g_radar_screen.cpp" "imu_meter.cpp"
          "lvgl_visual_system.cpp" "navigation.cpp"
          "presenter.cpp" "ready_screen.cpp" "rest_session.cpp" "review_cards.cpp" "session_trigger.cpp" "session_review.cpp" "session_review_screen.cpp"
          "settings_editor.cpp" "settings_screen.cpp"