Add spell-check exception

This PR introduces a Nix flake, allowing for InfiniTime to be built as a
Flake, including a FHS development environment.

It's derived from #1850 and
c57c57f3c6.

We also introduce `flake-compat`, allowing for non-Flake Nix mahcines to
use the project as-is, both for building (`default.nix`), and
development (`shell.nix`).

Additionally, we introduce `.envrc`, meaning that with `direnv`, the Nix
Flake is activated automatically.

Fixes #1850.

Signed-off-by: Dom Rodriguez <shymega@shymega.org.uk>

.envrc

@@ -0,0 +1 @@
+use flake

.vscode/settings.json

@@ -66,5 +66,8 @@
         "streambuf": "cpp",
         "cinttypes": "cpp",
         "typeinfo": "cpp"
-    }
+    },
+    "cSpell.words": [
+        "Pinetime"
+    ]
 }

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.10)
 
 set(CMAKE_BUILD_TYPE Release CACHE STRING "Choose Debug or Release")
 
-project(pinetime VERSION 1.14.0 LANGUAGES C CXX ASM)
+project(pinetime VERSION 1.15.1 LANGUAGES C CXX ASM)
 
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_CXX_STANDARD 20)

default.nix

@@ -0,0 +1,10 @@
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = lock.nodes.flake-compat.locked.url or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).defaultNix

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "flake-compat": {
+      "locked": {
+        "lastModified": 1696426674,
+        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
+        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
+        "revCount": 57,
+        "type": "tarball",
+        "url": "https://api.flakehub.com/f/pinned/edolstra/flake-compat/1.0.1/018afb31-abd1-7bff-a5e4-cff7e18efb7a/source.tar.gz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://flakehub.com/f/edolstra/flake-compat/1.tar.gz"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1725634671,
+        "narHash": "sha256-v3rIhsJBOMLR8e/RNWxr828tB+WywYIoajrZKFM+0Gg=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "574d1eac1c200690e27b8eb4e24887f8df7ac27c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,114 @@
+{
+  description = "A very basic flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-compat.url = "https://flakehub.com/f/edolstra/flake-compat/1.tar.gz";
+  };
+
+  outputs = { self, ... }@inputs:
+    let
+      forAllSystems = function:
+        inputs.nixpkgs.lib.genAttrs [
+          "x86_64-linux"
+          "aarch64-linux"
+        ]
+          (system: function (import inputs.nixpkgs {
+            inherit system;
+            config.allowUnfree = true;
+          }));
+    in
+    {
+      packages = forAllSystems (pkgs:
+        let
+          infinitime-nrf5-sdk = pkgs.nrf5-sdk.overrideAttrs (old: {
+            version = "15.3.0";
+            src = pkgs.fetchzip {
+              url = "https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/sdks/nrf5/binaries/nrf5sdk153059ac345.zip";
+              sha256 = "sha256-pfmhbpgVv5x2ju489XcivguwpnofHbgVA7bFUJRTj08=";
+            };
+          });
+        in
+        with pkgs; {
+          default = stdenv.mkDerivation rec {
+            name = "infinitime";
+
+            src = fetchFromGitea {
+              domain = "git.techwork.zone";
+              owner = "scott";
+              repo = "InfiniTime";
+              rev = "1.15.1";
+              hash = "sha256-9cy7qYRZrg7qZZwQzYeMIZivGLZ5uGUoTyPgHEvdnZ8=";
+              fetchSubmodules = true;
+            };
+
+            nativeBuildInputs = [
+              cmake
+              nodePackages.lv_font_conv
+              python3
+              python3.pkgs.cbor
+              python3.pkgs.click
+              python3.pkgs.cryptography
+              python3.pkgs.intelhex
+              python3.pkgs.pillow
+              adafruit-nrfutil
+              patch
+              git
+            ];
+
+            postPatch = ''
+              # /usr/bin/env is not available in the build sandbox
+              substituteInPlace src/displayapp/fonts/generate.py --replace "'/usr/bin/env', 'patch'" "'patch'"
+              substituteInPlace tools/mcuboot/imgtool.py --replace "/usr/bin/env python3" "${python3}/bin/python3"
+            '';
+
+            cmakeFlags = [
+              ''-DARM_NONE_EABI_TOOLCHAIN_PATH=${gcc-arm-embedded-10}''
+              ''-DNRF5_SDK_PATH=${infinitime-nrf5-sdk}/share/nRF5_SDK''
+              ''-DBUILD_DFU=1''
+              ''-DBUILD_RESOURCES=1''
+              ''-DCMAKE_SOURCE_DIR=${src}''
+            ];
+
+            installPhase = ''
+              SOURCES_DIR=${src} BUILD_DIR=. OUTPUT_DIR=$out ./post_build.sh
+            '';
+          };
+        });
+
+      devShells = forAllSystems (pkgs:
+        let
+          infinitime-nrf5-sdk = pkgs.nrf5-sdk.overrideAttrs (old: {
+            version = "15.3.0";
+            src = pkgs.fetchzip {
+              url = "https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/sdks/nrf5/binaries/nrf5sdk153059ac345.zip";
+              sha256 = "sha256-pfmhbpgVv5x2ju489XcivguwpnofHbgVA7bFUJRTj08=";
+            };
+          });
+        in
+        {
+          default =
+            pkgs.buildFHSUserEnv {
+              name = "infinitime-devenv";
+              # build tools
+              targetPkgs = pkgs: (with pkgs; [
+                cmake
+                nodePackages.lv_font_conv
+                python3
+                python3.pkgs.cbor
+                python3.pkgs.click
+                python3.pkgs.cryptography
+                python3.pkgs.intelhex
+                adafruit-nrfutil
+
+                (pkgs.writeShellScriptBin "cmake_infinitime" ''
+                  cmake -DARM_NONE_EABI_TOOLCHAIN_PATH="${pkgs.gcc-arm-embedded-10}" \
+                        -DNRF5_SDK_PATH="${infinitime-nrf5-sdk}/share/nRF5_SDK" \
+                        "$@"
+                '')
+              ]);
+            };
+        });
+    };
+}
+      

shell.nix

@@ -0,0 +1,10 @@
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = lock.nodes.flake-compat.locked.url or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).shellNix

src/CMakeLists.txt

@@ -411,6 +411,7 @@ list(APPEND SOURCE_FILES
         displayapp/screens/settings/SettingWeatherFormat.cpp
         displayapp/screens/settings/SettingWakeUp.cpp
         displayapp/screens/settings/SettingDisplay.cpp
+        displayapp/screens/settings/SettingHeartRate.cpp
         displayapp/screens/settings/SettingSteps.cpp
         displayapp/screens/settings/SettingSetDateTime.cpp
         displayapp/screens/settings/SettingSetDate.cpp

src/components/settings/Settings.cpp

@@ -8,13 +8,11 @@ Settings::Settings(Pinetime::Controllers::FS& fs) : fs {fs} {
 }
 
 void Settings::Init() {
-
   // Load default settings from Flash
   LoadSettingsFromFile();
 }
 
 void Settings::SaveSettings() {
-
   // verify if is necessary to save
   if (settingsChanged) {
     SaveSettingsToFile();

src/components/settings/Settings.h

@@ -50,6 +50,17 @@ namespace Pinetime {
         int colorIndex = 0;
       };
 
+      enum class HeartRateBackgroundMeasurementInterval : uint8_t {
+        Off,
+        Continuous,
+        TenSeconds,
+        ThirtySeconds,
+        OneMinute,
+        FiveMinutes,
+        TenMinutes,
+        ThirtyMinutes,
+      };
+
       Settings(Pinetime::Controllers::FS& fs);
 
       Settings(const Settings&) = delete;
@@ -298,10 +309,21 @@ namespace Pinetime {
         return bleRadioEnabled;
       };
 
+      HeartRateBackgroundMeasurementInterval GetHeartRateBackgroundMeasurementInterval() const {
+        return settings.heartRateBackgroundMeasurementInterval;
+      }
+
+      void SetHeartRateBackgroundMeasurementInterval(HeartRateBackgroundMeasurementInterval newHeartRateBackgroundMeasurementInterval) {
+        if (newHeartRateBackgroundMeasurementInterval != settings.heartRateBackgroundMeasurementInterval) {
+          settingsChanged = true;
+        }
+        settings.heartRateBackgroundMeasurementInterval = newHeartRateBackgroundMeasurementInterval;
+      }
+
     private:
       Pinetime::Controllers::FS& fs;
 
-      static constexpr uint32_t settingsVersion = 0x0008;
+      static constexpr uint32_t settingsVersion = 0x0009;
 
       struct SettingsData {
         uint32_t version = settingsVersion;
@@ -325,6 +347,8 @@ namespace Pinetime {
         uint16_t shakeWakeThreshold = 150;
 
         Controllers::BrightnessController::Levels brightLevel = Controllers::BrightnessController::Levels::Medium;
+
+        HeartRateBackgroundMeasurementInterval heartRateBackgroundMeasurementInterval = HeartRateBackgroundMeasurementInterval::Off;
       };
 
       SettingsData settings;

src/displayapp/DisplayApp.cpp

@@ -47,6 +47,7 @@
 #include "displayapp/screens/settings/SettingSteps.h"
 #include "displayapp/screens/settings/SettingSetDateTime.h"
 #include "displayapp/screens/settings/SettingChimes.h"
+#include "displayapp/screens/settings/SettingHeartRate.h"
 #include "displayapp/screens/settings/SettingShakeThreshold.h"
 #include "displayapp/screens/settings/SettingBluetooth.h"
 
@@ -333,7 +334,7 @@ void DisplayApp::Refresh() {
         } else {
           LoadNewScreen(Apps::Timer, DisplayApp::FullRefreshDirections::Up);
         }
-        motorController.RunForDuration(35);
+        motorController.StartRinging();
         break;
       case Messages::AlarmTriggered:
         if (currentApp == Apps::Alarm) {
@@ -564,6 +565,9 @@ void DisplayApp::LoadScreen(Apps app, DisplayApp::FullRefreshDirections directio
     case Apps::SettingWakeUp:
       currentScreen = std::make_unique<Screens::SettingWakeUp>(settingsController);
       break;
+    case Apps::SettingHeartRate:
+      currentScreen = std::make_unique<Screens::SettingHeartRate>(settingsController);
+      break;
     case Apps::SettingDisplay:
       currentScreen = std::make_unique<Screens::SettingDisplay>(this, settingsController);
       break;

src/displayapp/apps/Apps.h.in

@@ -35,6 +35,7 @@ namespace Pinetime {
       SettingWatchFace,
       SettingTimeFormat,
       SettingWeatherFormat,
+      SettingHeartRate,
       SettingDisplay,
       SettingWakeUp,
       SettingSteps,

src/displayapp/screens/settings/SettingHeartRate.cpp

@@ -0,0 +1,75 @@
+#include "displayapp/screens/settings/SettingHeartRate.h"
+#include <lvgl/lvgl.h>
+#include "displayapp/screens/Styles.h"
+#include "displayapp/screens/Screen.h"
+#include "displayapp/screens/Symbols.h"
+#include <array>
+#include <algorithm>
+
+using namespace Pinetime::Applications::Screens;
+
+namespace {
+  void event_handler(lv_obj_t* obj, lv_event_t event) {
+    auto* screen = static_cast<SettingHeartRate*>(obj->user_data);
+    screen->UpdateSelected(obj, event);
+  }
+}
+
+constexpr std::array<Option, 8> SettingHeartRate::options;
+
+SettingHeartRate::SettingHeartRate(Pinetime::Controllers::Settings& settingsController) : settingsController {settingsController} {
+
+  lv_obj_t* container1 = lv_cont_create(lv_scr_act(), nullptr);
+
+  lv_obj_set_style_local_bg_opa(container1, LV_CONT_PART_MAIN, LV_STATE_DEFAULT, LV_OPA_TRANSP);
+  lv_obj_set_style_local_pad_all(container1, LV_CONT_PART_MAIN, LV_STATE_DEFAULT, 5);
+  lv_obj_set_style_local_pad_inner(container1, LV_CONT_PART_MAIN, LV_STATE_DEFAULT, 5);
+  lv_obj_set_style_local_border_width(container1, LV_CONT_PART_MAIN, LV_STATE_DEFAULT, 0);
+
+  lv_obj_set_pos(container1, 10, 60);
+  lv_obj_set_width(container1, LV_HOR_RES - 20);
+  lv_obj_set_height(container1, LV_VER_RES - 50);
+  lv_cont_set_layout(container1, LV_LAYOUT_PRETTY_TOP);
+
+  lv_obj_t* title = lv_label_create(lv_scr_act(), nullptr);
+  lv_label_set_text_static(title, "Backg. Interval");
+  lv_label_set_text(title, "Backg. Interval");
+  lv_label_set_align(title, LV_LABEL_ALIGN_CENTER);
+  lv_obj_align(title, lv_scr_act(), LV_ALIGN_IN_TOP_MID, 10, 15);
+
+  lv_obj_t* icon = lv_label_create(lv_scr_act(), nullptr);
+  lv_obj_set_style_local_text_color(icon, LV_LABEL_PART_MAIN, LV_STATE_DEFAULT, LV_COLOR_RED);
+  lv_label_set_text_static(icon, Symbols::heartBeat);
+  lv_label_set_align(icon, LV_LABEL_ALIGN_CENTER);
+  lv_obj_align(icon, title, LV_ALIGN_OUT_LEFT_MID, -10, 0);
+
+  for (unsigned int i = 0; i < options.size(); i++) {
+    cbOption[i] = lv_checkbox_create(container1, nullptr);
+    lv_checkbox_set_text(cbOption[i], options[i].name);
+    cbOption[i]->user_data = this;
+    lv_obj_set_event_cb(cbOption[i], event_handler);
+    SetRadioButtonStyle(cbOption[i]);
+
+    if (settingsController.GetHeartRateBackgroundMeasurementInterval() == options[i].interval) {
+      lv_checkbox_set_checked(cbOption[i], true);
+    }
+  }
+}
+
+SettingHeartRate::~SettingHeartRate() {
+  lv_obj_clean(lv_scr_act());
+  settingsController.SaveSettings();
+}
+
+void SettingHeartRate::UpdateSelected(lv_obj_t* object, lv_event_t event) {
+  if (event == LV_EVENT_CLICKED) {
+    for (unsigned int i = 0; i < options.size(); i++) {
+      if (object == cbOption[i]) {
+        lv_checkbox_set_checked(cbOption[i], true);
+        settingsController.SetHeartRateBackgroundMeasurementInterval(options[i].interval);
+      } else {
+        lv_checkbox_set_checked(cbOption[i], false);
+      }
+    }
+  }
+}

src/displayapp/screens/settings/SettingHeartRate.h

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <cstdint>
+#include <lvgl/lvgl.h>
+
+#include "components/settings/Settings.h"
+#include "displayapp/screens/ScreenList.h"
+#include "displayapp/screens/Screen.h"
+#include "displayapp/screens/Symbols.h"
+#include "displayapp/screens/CheckboxList.h"
+
+namespace Pinetime {
+
+  namespace Applications {
+    namespace Screens {
+
+      struct Option {
+        const Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval interval;
+        const char* name;
+      };
+
+      class SettingHeartRate : public Screen {
+      public:
+        SettingHeartRate(Pinetime::Controllers::Settings& settings);
+        ~SettingHeartRate() override;
+
+        void UpdateSelected(lv_obj_t* object, lv_event_t event);
+
+      private:
+        Pinetime::Controllers::Settings& settingsController;
+
+        static constexpr std::array<Option, 8> options = {{
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Off, " Off"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Continuous, "Cont"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::TenSeconds, " 10s"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::ThirtySeconds, " 30s"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::OneMinute, "  1m"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::FiveMinutes, "  5m"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::TenMinutes, " 10m"},
+          {Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::ThirtyMinutes, " 30m"},
+        }};
+
+        lv_obj_t* cbOption[options.size()];
+      };
+    }
+  }
+}

src/displayapp/screens/settings/Settings.h

@@ -38,15 +38,16 @@ namespace Pinetime {
           {Symbols::home, "Watch face", Apps::SettingWatchFace},
 
           {Symbols::shoe, "Steps", Apps::SettingSteps},
+          {Symbols::heartBeat, "Heartrate", Apps::SettingHeartRate},
           {Symbols::clock, "Date&Time", Apps::SettingSetDateTime},
           {Symbols::cloudSunRain, "Weather", Apps::SettingWeatherFormat},
-          {Symbols::batteryHalf, "Battery", Apps::BatteryInfo},
 
+          {Symbols::batteryHalf, "Battery", Apps::BatteryInfo},
           {Symbols::clock, "Chimes", Apps::SettingChimes},
           {Symbols::tachometer, "Shake Calib.", Apps::SettingShakeThreshold},
           {Symbols::check, "Firmware", Apps::FirmwareValidation},
-          {Symbols::bluetooth, "Bluetooth", Apps::SettingBluetooth},
 
+          {Symbols::bluetooth, "Bluetooth", Apps::SettingBluetooth},
           {Symbols::list, "About", Apps::SysInfo},
 
           // {Symbols::none, "None", Apps::None},

src/heartratetask/HeartRateTask.cpp

@@ -5,8 +5,23 @@
 
 using namespace Pinetime::Applications;
 
-HeartRateTask::HeartRateTask(Drivers::Hrs3300& heartRateSensor, Controllers::HeartRateController& controller)
+TickType_t CurrentTaskDelay(HeartRateTask::States state, TickType_t ppgDeltaTms) {
-  : heartRateSensor {heartRateSensor}, controller {controller} {
+  switch (state) {
+    case HeartRateTask::States::ScreenOnAndMeasuring:
+    case HeartRateTask::States::ScreenOffAndMeasuring:
+      return ppgDeltaTms;
+    case HeartRateTask::States::ScreenOffAndWaiting:
+      return pdMS_TO_TICKS(1000);
+    default:
+      return portMAX_DELAY;
+  }
+}
+
+
+HeartRateTask::HeartRateTask(Drivers::Hrs3300& heartRateSensor,
+                             Controllers::HeartRateController& controller,
+                             Controllers::Settings& settings)
+  : heartRateSensor {heartRateSensor}, controller {controller}, settings {settings} {
 }
 
 void HeartRateTask::Start() {
@@ -25,77 +40,40 @@ void HeartRateTask::Process(void* instance) {
 
 void HeartRateTask::Work() {
   int lastBpm = 0;
-  while (true) {
-    Messages msg;
-    uint32_t delay;
-    if (state == States::Running) {
-      if (measurementStarted) {
-        delay = ppg.deltaTms;
-      } else {
-        delay = 100;
-      }
-    } else {
-      delay = portMAX_DELAY;
-    }
 
-    if (xQueueReceive(messageQueue, &msg, delay)) {
+  while (true) {
+    TickType_t delay = CurrentTaskDelay(state, ppg.deltaTms);
+    Messages msg;
+
+    if (xQueueReceive(messageQueue, &msg, delay) == pdTRUE) {
       switch (msg) {
         case Messages::GoToSleep:
-          StopMeasurement();
+          HandleGoToSleep();
-          state = States::Idle;
           break;
         case Messages::WakeUp:
-          state = States::Running;
+          HandleWakeUp();
-          if (measurementStarted) {
-            lastBpm = 0;
-            StartMeasurement();
-          }
           break;
         case Messages::StartMeasurement:
-          if (measurementStarted) {
+          HandleStartMeasurement(&lastBpm);
-            break;
-          }
-          lastBpm = 0;
-          StartMeasurement();
-          measurementStarted = true;
           break;
         case Messages::StopMeasurement:
-          if (!measurementStarted) {
+          HandleStopMeasurement();
-            break;
-          }
-          StopMeasurement();
-          measurementStarted = false;
           break;
       }
     }
 
-    if (measurementStarted) {
+    switch (state) {
-      int8_t ambient = ppg.Preprocess(heartRateSensor.ReadHrs(), heartRateSensor.ReadAls());
+      case States::ScreenOffAndWaiting:
-      int bpm = ppg.HeartRate();
+        HandleBackgroundWaiting();
-
+        break;
-      // If ambient light detected or a reset requested (bpm < 0)
+      case States::ScreenOffAndMeasuring:
-      if (ambient > 0) {
+      case States::ScreenOnAndMeasuring:
-        // Reset all DAQ buffers
+        HandleSensorData(&lastBpm);
-        ppg.Reset(true);
+        break;
-        // Force state to NotEnoughData (below)
+      case States::ScreenOffAndStopped:
-        lastBpm = 0;
+      case States::ScreenOnAndStopped:
-        bpm = 0;
+        // nothing to do -> ignore
-      } else if (bpm < 0) {
+        break;
-        // Reset all DAQ buffers except HRS buffer
-        ppg.Reset(false);
-        // Set HR to zero and update
-        bpm = 0;
-        controller.Update(Controllers::HeartRateController::States::Running, bpm);
-      }
-
-      if (lastBpm == 0 && bpm == 0) {
-        controller.Update(Controllers::HeartRateController::States::NotEnoughData, bpm);
-      }
-
-      if (bpm != 0) {
-        lastBpm = bpm;
-        controller.Update(Controllers::HeartRateController::States::Running, lastBpm);
-      }
     }
   }
 }
@@ -110,6 +88,7 @@ void HeartRateTask::StartMeasurement() {
   heartRateSensor.Enable();
   ppg.Reset(true);
   vTaskDelay(100);
+  measurementStart = xTaskGetTickCount();
 }
 
 void HeartRateTask::StopMeasurement() {
@@ -117,3 +96,165 @@ void HeartRateTask::StopMeasurement() {
   ppg.Reset(true);
   vTaskDelay(100);
 }
+
+void HeartRateTask::StartWaiting() {
+  StopMeasurement();
+  backgroundWaitingStart = xTaskGetTickCount();
+}
+
+void HeartRateTask::HandleGoToSleep() {
+  switch (state) {
+    case States::ScreenOnAndStopped:
+      state = States::ScreenOffAndStopped;
+      break;
+    case States::ScreenOnAndMeasuring:
+      state = States::ScreenOffAndMeasuring;
+      break;
+    case States::ScreenOffAndStopped:
+    case States::ScreenOffAndWaiting:
+    case States::ScreenOffAndMeasuring:
+      // shouldn't happen -> ignore
+      break;
+  }
+}
+
+void HeartRateTask::HandleWakeUp() {
+  switch (state) {
+    case States::ScreenOffAndStopped:
+      state = States::ScreenOnAndStopped;
+      break;
+    case States::ScreenOffAndMeasuring:
+      state = States::ScreenOnAndMeasuring;
+      break;
+    case States::ScreenOffAndWaiting:
+      state = States::ScreenOnAndMeasuring;
+      StartMeasurement();
+      break;
+    case States::ScreenOnAndStopped:
+    case States::ScreenOnAndMeasuring:
+      // shouldn't happen -> ignore
+      break;
+  }
+}
+
+void HeartRateTask::HandleStartMeasurement(int* lastBpm) {
+  switch (state) {
+    case States::ScreenOffAndStopped:
+    case States::ScreenOnAndStopped:
+      state = States::ScreenOnAndMeasuring;
+      *lastBpm = 0;
+      StartMeasurement();
+      break;
+    case States::ScreenOnAndMeasuring:
+    case States::ScreenOffAndMeasuring:
+    case States::ScreenOffAndWaiting:
+      // shouldn't happen -> ignore
+      break;
+  }
+}
+
+void HeartRateTask::HandleStopMeasurement() {
+  switch (state) {
+    case States::ScreenOnAndMeasuring:
+      state = States::ScreenOnAndStopped;
+      StopMeasurement();
+      break;
+    case States::ScreenOffAndMeasuring:
+    case States::ScreenOffAndWaiting:
+      state = States::ScreenOffAndStopped;
+      StopMeasurement();
+      break;
+    case States::ScreenOnAndStopped:
+    case States::ScreenOffAndStopped:
+      // shouldn't happen -> ignore
+      break;
+  }
+}
+
+void HeartRateTask::HandleBackgroundWaiting() {
+  if (!IsBackgroundMeasurementActivated()) {
+    return;
+  }
+
+  TickType_t ticksSinceWaitingStart = xTaskGetTickCount() - backgroundWaitingStart;
+  if (ticksSinceWaitingStart >= GetHeartRateBackgroundMeasurementIntervalInTicks()) {
+    state = States::ScreenOffAndMeasuring;
+    StartMeasurement();
+  }
+}
+
+void HeartRateTask::HandleSensorData(int* lastBpm) {
+  int8_t ambient = ppg.Preprocess(heartRateSensor.ReadHrs(), heartRateSensor.ReadAls());
+  int bpm = ppg.HeartRate();
+
+  // If ambient light detected or a reset requested (bpm < 0)
+  if (ambient > 0) {
+    // Reset all DAQ buffers
+    ppg.Reset(true);
+  } else if (bpm < 0) {
+    // Reset all DAQ buffers except HRS buffer
+    ppg.Reset(false);
+    // Set HR to zero and update
+    bpm = 0;
+  }
+
+  if (*lastBpm == 0 && bpm == 0) {
+    controller.Update(Controllers::HeartRateController::States::NotEnoughData, bpm);
+  }
+
+  if (bpm != 0) {
+    *lastBpm = bpm;
+    controller.Update(Controllers::HeartRateController::States::Running, bpm);
+    if (state == States::ScreenOnAndMeasuring || IsContinuousModeActivated()) {
+      return;
+    }
+    if (state == States::ScreenOffAndMeasuring) {
+      state = States::ScreenOffAndWaiting;
+      StartWaiting();
+    }
+  }
+  TickType_t ticksSinceMeasurementStart = xTaskGetTickCount() - measurementStart;
+  if (bpm == 0 && state == States::ScreenOffAndMeasuring && !IsContinuousModeActivated() &&
+      ticksSinceMeasurementStart >= DURATION_UNTIL_BACKGROUND_MEASUREMENT_IS_STOPPED) {
+    state = States::ScreenOffAndWaiting;
+    StartWaiting();
+  }
+}
+
+TickType_t HeartRateTask::GetHeartRateBackgroundMeasurementIntervalInTicks() {
+  int ms;
+  switch (settings.GetHeartRateBackgroundMeasurementInterval()) {
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::TenSeconds:
+      ms = 10 * 1000;
+      break;
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::ThirtySeconds:
+      ms = 30 * 1000;
+      break;
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::OneMinute:
+      ms = 60 * 1000;
+      break;
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::FiveMinutes:
+      ms = 5 * 60 * 1000;
+      break;
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::TenMinutes:
+      ms = 10 * 60 * 1000;
+      break;
+    case Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::ThirtyMinutes:
+      ms = 30 * 60 * 1000;
+      break;
+    default:
+      ms = 0;
+      break;
+  }
+  return pdMS_TO_TICKS(ms);
+}
+
+bool HeartRateTask::IsContinuousModeActivated() {
+  return settings.GetHeartRateBackgroundMeasurementInterval() ==
+         Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Continuous;
+}
+
+bool HeartRateTask::IsBackgroundMeasurementActivated() {
+  return settings.GetHeartRateBackgroundMeasurementInterval() !=
+         Pinetime::Controllers::Settings::HeartRateBackgroundMeasurementInterval::Off;
+}

src/heartratetask/HeartRateTask.h

@@ -3,6 +3,9 @@
 #include <task.h>
 #include <queue.h>
 #include <components/heartrate/Ppg.h>
+#include "components/settings/Settings.h"
+
+#define DURATION_UNTIL_BACKGROUND_MEASUREMENT_IS_STOPPED pdMS_TO_TICKS(30 * 1000)
 
 namespace Pinetime {
   namespace Drivers {
@@ -16,10 +19,24 @@ namespace Pinetime {
   namespace Applications {
     class HeartRateTask {
     public:
-      enum class Messages : uint8_t { GoToSleep, WakeUp, StartMeasurement, StopMeasurement };
+      enum class Messages : uint8_t {
-      enum class States { Idle, Running };
+        GoToSleep,
+        WakeUp,
+        StartMeasurement,
+        StopMeasurement
+      };
 
-      explicit HeartRateTask(Drivers::Hrs3300& heartRateSensor, Controllers::HeartRateController& controller);
+      enum class States {
+        ScreenOnAndStopped,
+        ScreenOnAndMeasuring,
+        ScreenOffAndStopped,
+        ScreenOffAndWaiting,
+        ScreenOffAndMeasuring
+      };
+
+      explicit HeartRateTask(Drivers::Hrs3300& heartRateSensor,
+                             Controllers::HeartRateController& controller,
+                             Controllers::Settings& settings);
       void Start();
       void Work();
       void PushMessage(Messages msg);
@@ -28,14 +45,29 @@ namespace Pinetime {
       static void Process(void* instance);
       void StartMeasurement();
       void StopMeasurement();
+      void StartWaiting();
+
+      void HandleGoToSleep();
+      void HandleWakeUp();
+      void HandleStartMeasurement(int* lastBpm);
+      void HandleStopMeasurement();
+
+      void HandleBackgroundWaiting();
+      void HandleSensorData(int* lastBpm);
+
+      TickType_t GetHeartRateBackgroundMeasurementIntervalInTicks();
+      bool IsContinuousModeActivated();
+      bool IsBackgroundMeasurementActivated();
 
       TaskHandle_t taskHandle;
       QueueHandle_t messageQueue;
-      States state = States::Running;
+      States state = States::ScreenOnAndStopped;
       Drivers::Hrs3300& heartRateSensor;
       Controllers::HeartRateController& controller;
+      Controllers::Settings& settings;
       Controllers::Ppg ppg;
-      bool measurementStarted = false;
+      TickType_t backgroundWaitingStart = 0;
+      TickType_t measurementStart = 0;
     };
 
   }

src/main.cpp

@@ -93,13 +93,13 @@ TimerHandle_t debounceChargeTimer;
 Pinetime::Controllers::Battery batteryController;
 Pinetime::Controllers::Ble bleController;
 
-Pinetime::Controllers::HeartRateController heartRateController;
-Pinetime::Applications::HeartRateTask heartRateApp(heartRateSensor, heartRateController);
-
 Pinetime::Controllers::FS fs {spiNorFlash};
 Pinetime::Controllers::Settings settingsController {fs};
 Pinetime::Controllers::MotorController motorController {};
 
+Pinetime::Controllers::HeartRateController heartRateController;
+Pinetime::Applications::HeartRateTask heartRateApp(heartRateSensor, heartRateController, settingsController);
+
 Pinetime::Controllers::DateTime dateTimeController {settingsController};
 Pinetime::Drivers::Watchdog watchdog;
 Pinetime::Controllers::NotificationManager notificationManager;