diff --git a/examples/UnitUnified/PlotToSerial/main/PlotToSerial.cpp b/examples/UnitUnified/PlotToSerial/main/PlotToSerial.cpp
index 8f6350b..f860770 100644
--- a/examples/UnitUnified/PlotToSerial/main/PlotToSerial.cpp
+++ b/examples/UnitUnified/PlotToSerial/main/PlotToSerial.cpp
@@ -23,13 +23,6 @@ m5::unit::UnitUnified Units;
 m5::unit::UnitHEART unitHeart;
 m5::max30100::HeartRate heartRate(100);
 
-uint32_t getSamplingRate(const m5::unit::max30100::Sampling rate) {
-    static constexpr uint32_t table[] = {50, 100, 167, 200, 400, 600, 800, 1000};
-    return table[m5::stl::to_underlying(rate)];
-}
-
-}  // namespace
-
 void setup() {
     M5.begin();
 
@@ -40,7 +33,7 @@ void setup() {
         cfg.pulseWidth   = m5::unit::max30100::LedPulseWidth::PW400;
         cfg.irCurrent    = m5::unit::max30100::CurrentControl::mA7_6;
         cfg.redCurrent   = m5::unit::max30100::CurrentControl::mA7_6;
-        heartRate.setSamplingRate(getSamplingRate(cfg.samplingRate));
+        heartRate.setSamplingRate(m5::max30100::HeartRate::getSamplingRate(cfg.samplingRate));
         heartRate.setThreshold(25.0f);  // depends on ir/redCurrent
         unitHeart.config(cfg);
     }
@@ -88,8 +81,7 @@ void loop() {
     Units.update();
     if (unitHeart.updated()) {
         while (unitHeart.available()) {
-            // M5_LOGI("\n>IR:%u\n>RED:%u", unitHeart.ir(),
-            // unitHeart.red());
+            M5_LOGI("\n>IR:%u\n>RED:%u", unitHeart.ir(), unitHeart.red());
             bool beat = heartRate.push_back((float)unitHeart.ir(), (float)unitHeart.red());
             if (beat) {
                 M5_LOGI("Beat!");
diff --git a/src/M5UnitUnifiedHEART.hpp b/src/M5UnitUnifiedHEART.hpp
index 8611da0..53927ee 100644
--- a/src/M5UnitUnifiedHEART.hpp
+++ b/src/M5UnitUnifiedHEART.hpp
@@ -14,6 +14,7 @@
 #define M5_UNIT_HEART_HPP
 
 #include "unit/unit_MAX30100.hpp"
+#include "utility/heart_rate.hpp"
 
 /*!
   @namespace m5
diff --git a/src/unit/unit_MAX30100.hpp b/src/unit/unit_MAX30100.hpp
index fcb96a7..514ceb5 100644
--- a/src/unit/unit_MAX30100.hpp
+++ b/src/unit/unit_MAX30100.hpp
@@ -296,11 +296,11 @@ class UnitMAX30100 : public Component, public PeriodicMeasurementAdapter<UnitMAX
 
     ///@name Measurement data by periodic
     ///@{
-    //! @brief Oldest CO2eq (ppm)
+    //! @brief Oldest IR
     inline uint16_t ir() const {
         return !empty() ? oldest().ir() : 0;
     }
-    //! @brief Oldest TVOC (ppb)
+    //! @brief Oldest Red
     inline uint16_t red() const {
         return !empty() ? oldest().red() : 0;
     }
diff --git a/src/utility/heart_rate.cpp b/src/utility/heart_rate.cpp
index 89b2ad1..082335d 100644
--- a/src/utility/heart_rate.cpp
+++ b/src/utility/heart_rate.cpp
@@ -123,6 +123,7 @@ bool HeartRate::push_back(const float ir, const float red) {
 
     // SpO2
     _acSqIR += _dcIR.result * _dcIR.result;
+    //_acSqRED += _dcRED.result * _dcRED.result;
     _acSqRED = _dcRED.result * _dcRED.result;
     ++_count;
     if (_beat) {
diff --git a/src/utility/heart_rate.hpp b/src/utility/heart_rate.hpp
index b7f2f1d..84d4ae2 100644
--- a/src/utility/heart_rate.hpp
+++ b/src/utility/heart_rate.hpp
@@ -13,6 +13,7 @@
 #include <deque>
 #include <cstddef>
 #include <m5_unit_component/types.hpp>
+#include "../unit/unit_max30100.hpp"
 
 namespace m5 {
 namespace max30100 {
@@ -42,12 +43,22 @@ struct butterworthFilter_t {
  */
 class HeartRate {
    public:
+    /*!
+      @brief Conversion m5::unit::max30100::Sampling to sapling rate
+      @param rate bm5::unit::max30100::Sampling value
+      @return Sampling rate
+     */
+    static uint32_t getSamplingRate(const m5::unit::max30100::Sampling rate) {
+        static constexpr uint32_t table[] = {50, 100, 167, 200, 400, 600, 800, 1000};
+        return table[m5::stl::to_underlying(rate)];
+    }
+
     /*!
       @param sr Sampling rate (e.g. 167 if max30100::Sampling::Rate167)
       @param threshold Threshold for detect beat (depends on ir/redCUrrent)
       @param store_size Stored data size(0U means auto)
      */
-    HeartRate(const uint32_t srate, const float threshold = 125.f, const size_t max_data_size = 0U);
+    explicit HeartRate(const uint32_t srate = 1, const float threshold = 125.f, const size_t max_data_size = 0U);
 
     ///@name Settings
     ///@{