added comments to flow sensor code and added flow rate to SD data (#31)

OPEnSLab-OSU · Feb 10, 2022 · 20d6df1 · 20d6df1
1 parent 1edf3ab
commit 20d6df1
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Showing 4 changed files with 25 additions and 9 deletions.
diff --git a/src/Application/App.hpp b/src/Application/App.hpp
@@ -216,21 +216,21 @@ class App : public KPController, public KPSerialInputObserver, public TaskObserv
         // Regular log header
         if (!SD.exists(config.logFile)) {
             File file = SD.open(config.logFile, FILE_WRITE);
-            KPStringBuilder<384> header{"UTC, Formatted Time, Task Name, Valve Number, Current "
+            KPStringBuilder<404> header{"UTC, Formatted Time, Task Name, Valve Number, Current "
                                         "State, Config Sample Time, Config Sample "
                                         "Pressure, Config Sample Volume, Temperature Recorded,"
-                                        "Max Pressure Recorded, Volume Recorded\n"};
+                                        "Max Pressure Recorded, Volume Recorded, Flow Rate\n"};
             file.println(header);
             file.close();
         }
 
         // Detail log header
         if (!SD.exists("detail.csv")) {
             File file = SD.open("detail.csv", FILE_WRITE);
-            KPStringBuilder<384> header{"UTC, Formatted Time, Task Name, Valve Number, Current "
+            KPStringBuilder<404> header{"UTC, Formatted Time, Task Name, Valve Number, Current "
                                         "State, Config Sample Time, Config Sample "
                                         "Pressure, Config Sample Volume, Temperature Recorded,"
-                                        "Pressure Recorded, Volume Recorded\n"};
+                                        "Pressure Recorded, Volume Recorded, Flow Rate\n"};
             file.println(header);
             file.close();
         }
@@ -333,7 +333,7 @@ class App : public KPController, public KPSerialInputObserver, public TaskObserv
                 formattedTime, "%u/%u/%u %02u:%02u:%02u GMT+0", year(utc), month(utc), day(utc),
                 hour(utc), minute(utc), second(utc));
 
-            KPStringBuilder<512> data{
+            KPStringBuilder<544> data{
                 utc,
                 ",",
                 formattedTime,
@@ -354,7 +354,9 @@ class App : public KPController, public KPSerialInputObserver, public TaskObserv
                 ",",
                 status.pressure,
                 ",",
-                status.waterVolume};
+                status.waterVolume,
+                ",",
+                status.waterFlow};
             log.println(data);
             log.flush();
             log.close();
@@ -372,7 +374,7 @@ class App : public KPController, public KPSerialInputObserver, public TaskObserv
             formattedTime, "%u/%u/%u %02u:%02u:%02u GMT+0", year(utc), month(utc), day(utc),
             hour(utc), minute(utc), second(utc));
 
-        KPStringBuilder<512> data{
+        KPStringBuilder<544> data{
             utc,
             ",",
             formattedTime,
@@ -393,7 +395,9 @@ class App : public KPController, public KPSerialInputObserver, public TaskObserv
             ",",
             status.maxPressure,
             ",",
-            status.waterVolume};
+            status.waterVolume,
+            ",",
+            status.waterFlow};
         log.println(data);
         log.flush();
         log.close();

diff --git a/src/Components/Sensor.hpp b/src/Components/Sensor.hpp
@@ -108,6 +108,9 @@ class Sensor {
         }
 
         // Lazy evaluation: last_update will never be initialized if the sensor is not enabled;
+        // last_update is initialized to millis() here in the first call, and then set below
+        // see link for another examples of static vars in functions: 
+        // https://www.tutorialspoint.com/what-is-the-lifetime-of-a-static-variable-in-a-cplusplus-function
         static long last_update = millis();
         if ((millis() - last_update) < updateInterval) {
             return ErrorCode::notReady;

diff --git a/src/Components/Sensors/TurbineFlowSensor.cpp b/src/Components/Sensors/TurbineFlowSensor.cpp
@@ -5,7 +5,9 @@ volatile unsigned long flowIntervalMicros;
 volatile bool flowUpdated;
 
 void flowTick() {
+	//This is the time interval since the last flowTick
 	flowIntervalMicros = micros() - lastFlowTick;
 	lastFlowTick	   = micros();
+	//make sure to read data
 	flowUpdated		   = true;
 }
diff --git a/src/Components/Sensors/TurbineFlowSensor.hpp b/src/Components/Sensors/TurbineFlowSensor.hpp
@@ -21,6 +21,7 @@ class TurbineFlowSensor : public Sensor<TurbineFlowSensorData> {
     void begin() override {
         lastFlowTick = micros();
         pinMode(A3, INPUT);
+        //sensor is updated once a second
         setUpdateFreq(1000);
     }
 
@@ -43,9 +44,15 @@ class TurbineFlowSensor : public Sensor<TurbineFlowSensorData> {
     SensorData read() override {
         if (flowUpdated) {
             flowUpdated = false;
-
+            //micro is 1e-6, so we divide the micros in a second with the flow interval
+            //to get the frequency
             auto hz = 1000000.0 / double(flowIntervalMicros);
+            //The spec sheet says that the output frequency is between 36.6 to 917 Hz
+            //So if hz is less than 37/36.6, then the flow is zero. Otherwise, interporlate
+            //between the frequency into the flow rate.
+            //flow that the sensor can record is between 0.1LPM and 2.5LPM
             lpm     = hz < 37 ? 0 : interpolate(hz, 37, 917, 0.110, 2.476);
+            //LPM * change in minute gives volume in liters
             volume += lpm * (flowIntervalMicros / 60000000.0);
             println("Volume: ", volume, ", LPM: ", lpm);
         } else {