8 files changed, 297 insertions, 0 deletions
diff --git a/src/components/heartrate/Biquad.cpp b/src/components/heartrate/Biquad.cpp
new file mode 100644
index 0000000..b7edd40
--- /dev/null
+++ b/src/components/heartrate/Biquad.cpp
@@ -0,0 +1,26 @@
+/*
+  SPDX-License-Identifier: LGPL-3.0-or-later
+  Original work Copyright (C) 2020 Daniel Thompson
+  C++ port Copyright (C) 2021 Jean-François Milants
+*/
+
+#include "components/heartrate/Biquad.h"
+
+using namespace Pinetime::Controllers;
+
+/** Original implementation from wasp-os : https://github.com/daniel-thompson/wasp-os/blob/master/wasp/ppg.py */
+Biquad::Biquad(float b0, float b1, float b2, float a1, float a2) : b0 {b0}, b1 {b1}, b2 {b2}, a1 {a1}, a2 {a2} {
+}
+
+float Biquad::Step(float x) {
+  auto v1 = this->v1;
+  auto v2 = this->v2;
+
+  auto v = x - (a1 * v1) - (a2 * v2);
+  auto y = (b0 * v) + (b1 * v1) + (b2 * v2);
+
+  this->v2 = v1;
+  this->v1 = v;
+
+  return y;
+}
diff --git a/src/components/heartrate/Biquad.h b/src/components/heartrate/Biquad.h
new file mode 100644
index 0000000..7c8ca58
--- /dev/null
+++ b/src/components/heartrate/Biquad.h
@@ -0,0 +1,22 @@
+#pragma once
+
+namespace Pinetime {
+  namespace Controllers {
+    /// Direct Form II Biquad Filter
+    class Biquad {
+    public:
+      Biquad(float b0, float b1, float b2, float a1, float a2);
+      float Step(float x);
+
+    private:
+      float b0;
+      float b1;
+      float b2;
+      float a1;
+      float a2;
+
+      float v1 = 0.0f;
+      float v2 = 0.0f;
+    };
+  }
+}
diff --git a/src/components/heartrate/HeartRateController.cpp b/src/components/heartrate/HeartRateController.cpp
new file mode 100644
index 0000000..e0d6927
--- /dev/null
+++ b/src/components/heartrate/HeartRateController.cpp
@@ -0,0 +1,35 @@
+#include "components/heartrate/HeartRateController.h"
+#include <heartratetask/HeartRateTask.h>
+#include <systemtask/SystemTask.h>
+
+using namespace Pinetime::Controllers;
+
+void HeartRateController::Update(HeartRateController::States newState, uint8_t heartRate) {
+  this->state = newState;
+  if (this->heartRate != heartRate) {
+    this->heartRate = heartRate;
+    service->OnNewHeartRateValue(heartRate);
+  }
+}
+
+void HeartRateController::Start() {
+  if (task != nullptr) {
+    state = States::NotEnoughData;
+    task->PushMessage(Pinetime::Applications::HeartRateTask::Messages::StartMeasurement);
+  }
+}
+
+void HeartRateController::Stop() {
+  if (task != nullptr) {
+    state = States::Stopped;
+    task->PushMessage(Pinetime::Applications::HeartRateTask::Messages::StopMeasurement);
+  }
+}
+
+void HeartRateController::SetHeartRateTask(Pinetime::Applications::HeartRateTask* task) {
+  this->task = task;
+}
+
+void HeartRateController::SetService(Pinetime::Controllers::HeartRateService* service) {
+  this->service = service;
+}
diff --git a/src/components/heartrate/HeartRateController.h b/src/components/heartrate/HeartRateController.h
new file mode 100644
index 0000000..a63f1a7
--- /dev/null
+++ b/src/components/heartrate/HeartRateController.h
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <cstdint>
+#include <components/ble/HeartRateService.h>
+
+namespace Pinetime {
+  namespace Applications {
+    class HeartRateTask;
+  }
+  namespace System {
+    class SystemTask;
+  }
+  namespace Controllers {
+    class HeartRateController {
+    public:
+      enum class States { Stopped, NotEnoughData, NoTouch, Running };
+
+      HeartRateController() = default;
+      void Start();
+      void Stop();
+      void Update(States newState, uint8_t heartRate);
+
+      void SetHeartRateTask(Applications::HeartRateTask* task);
+      States State() const {
+        return state;
+      }
+      uint8_t HeartRate() const {
+        return heartRate;
+      }
+
+      void SetService(Pinetime::Controllers::HeartRateService* service);
+
+    private:
+      Applications::HeartRateTask* task = nullptr;
+      States state = States::Stopped;
+      uint8_t heartRate = 0;
+      Pinetime::Controllers::HeartRateService* service = nullptr;
+    };
+  }
+}
+\ No newline at end of file
diff --git a/src/components/heartrate/Ppg.cpp b/src/components/heartrate/Ppg.cpp
new file mode 100644
index 0000000..a5d8369
--- /dev/null
+++ b/src/components/heartrate/Ppg.cpp
@@ -0,0 +1,99 @@
+/*
+  SPDX-License-Identifier: LGPL-3.0-or-later
+  Original work Copyright (C) 2020 Daniel Thompson
+  C++ port Copyright (C) 2021 Jean-François Milants
+*/
+
+#include "components/heartrate/Ppg.h"
+#include <vector>
+#include <nrf_log.h>
+using namespace Pinetime::Controllers;
+
+/** Original implementation from wasp-os : https://github.com/daniel-thompson/wasp-os/blob/master/wasp/ppg.py */
+namespace {
+  int Compare(int8_t* d1, int8_t* d2, size_t count) {
+    int e = 0;
+    for (size_t i = 0; i < count; i++) {
+      auto d = d1[i] - d2[i];
+      e += d * d;
+    }
+    return e;
+  }
+
+  int CompareShift(int8_t* d, int shift, size_t count) {
+    return Compare(d + shift, d, count - shift);
+  }
+
+  int Trough(int8_t* d, size_t size, uint8_t mn, uint8_t mx) {
+    auto z2 = CompareShift(d, mn - 2, size);
+    auto z1 = CompareShift(d, mn - 1, size);
+    for (int i = mn; i < mx + 1; i++) {
+      auto z = CompareShift(d, i, size);
+      if (z2 > z1 && z1 < z)
+        return i;
+      z2 = z1;
+      z1 = z;
+    }
+    return -1;
+  }
+}
+
+Ppg::Ppg()
+  : hpf {0.87033078, -1.74066156, 0.87033078, -1.72377617, 0.75754694},
+    agc {20, 0.971, 2},
+    lpf {0.11595249, 0.23190498, 0.11595249, -0.72168143, 0.18549138} {
+}
+
+int8_t Ppg::Preprocess(float spl) {
+  spl -= offset;
+  spl = hpf.Step(spl);
+  spl = agc.Step(spl);
+  spl = lpf.Step(spl);
+
+  auto spl_int = static_cast<int8_t>(spl);
+
+  if (dataIndex < 200)
+    data[dataIndex++] = spl_int;
+  return spl_int;
+}
+
+float Ppg::HeartRate() {
+  if (dataIndex < 200)
+    return 0;
+
+  NRF_LOG_INFO("PREPROCESS, offset = %d", offset);
+  auto hr = ProcessHeartRate();
+  dataIndex = 0;
+  return hr;
+}
+float Ppg::ProcessHeartRate() {
+  auto t0 = Trough(data.data(), dataIndex, 7, 48);
+  if (t0 < 0)
+    return 0;
+
+  float t1 = t0 * 2;
+  t1 = Trough(data.data(), dataIndex, t1 - 5, t1 + 5);
+  if (t1 < 0)
+    return 0;
+
+  float t2 = static_cast<int>(t1 * 3) / 2;
+  t2 = Trough(data.data(), dataIndex, t2 - 5, t2 + 5);
+  if (t2 < 0)
+    return 0;
+
+  float t3 = static_cast<int>(t2 * 4) / 3;
+  t3 = Trough(data.data(), dataIndex, t3 - 4, t3 + 4);
+  if (t3 < 0)
+    return static_cast<int>(60 * 24 * 3) / static_cast<int>(t2);
+
+  return static_cast<int>(60 * 24 * 4) / static_cast<int>(t3);
+}
+
+void Ppg::SetOffset(uint16_t offset) {
+  this->offset = offset;
+  dataIndex = 0;
+}
+
+void Ppg::Reset() {
+  dataIndex = 0;
+}
diff --git a/src/components/heartrate/Ppg.h b/src/components/heartrate/Ppg.h
new file mode 100644
index 0000000..7000c87
--- /dev/null
+++ b/src/components/heartrate/Ppg.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include "components/heartrate/Biquad.h"
+#include "components/heartrate/Ptagc.h"
+
+namespace Pinetime {
+  namespace Controllers {
+    class Ppg {
+    public:
+      Ppg();
+      int8_t Preprocess(float spl);
+      float HeartRate();
+
+      void SetOffset(uint16_t i);
+      void Reset();
+
+    private:
+      std::array<int8_t, 200> data;
+      size_t dataIndex = 0;
+      float offset;
+      Biquad hpf;
+      Ptagc agc;
+      Biquad lpf;
+
+      float ProcessHeartRate();
+    };
+  }
+}
diff --git a/src/components/heartrate/Ptagc.cpp b/src/components/heartrate/Ptagc.cpp
new file mode 100644
index 0000000..1c60bc2
--- /dev/null
+++ b/src/components/heartrate/Ptagc.cpp
@@ -0,0 +1,27 @@
+/*
+  SPDX-License-Identifier: LGPL-3.0-or-later
+  Original work Copyright (C) 2020 Daniel Thompson
+  C++ port Copyright (C) 2021 Jean-François Milants
+*/
+
+#include "components/heartrate/Ptagc.h"
+#include <cmath>
+
+using namespace Pinetime::Controllers;
+
+/** Original implementation from wasp-os : https://github.com/daniel-thompson/wasp-os/blob/master/wasp/ppg.py */
+Ptagc::Ptagc(float start, float decay, float threshold) : peak {start}, decay {decay}, boost {1.0f / decay}, threshold {threshold} {
+}
+
+float Ptagc::Step(float spl) {
+  if (std::abs(spl) > peak)
+    peak *= boost;
+  else
+    peak *= decay;
+
+  if ((spl > (peak * threshold)) || (spl < (peak * -threshold)))
+    return 0.0f;
+
+  spl = 100.0f * spl / (2.0f * peak);
+  return spl;
+}
diff --git a/src/components/heartrate/Ptagc.h b/src/components/heartrate/Ptagc.h
new file mode 100644
index 0000000..3476636
--- /dev/null
+++ b/src/components/heartrate/Ptagc.h
@@ -0,0 +1,17 @@
+#pragma once
+
+namespace Pinetime {
+  namespace Controllers {
+    class Ptagc {
+    public:
+      Ptagc(float start, float decay, float threshold);
+      float Step(float spl);
+
+    private:
+      float peak;
+      float decay;
+      float boost;
+      float threshold;
+    };
+  }
+}