Add temperature compensation feature

node-wifi-mqtt-homie-battery/CHANGES.rst

@@ -10,23 +10,27 @@ in-progress
 - Set some custom settings as default, limited at the moment by issue:
  https://github.com/marvinroger/homie-esp8266/issues/323
 
+2017-04-04 0.9.4
+================
+- Add temperature compensation in gram per degree.
+
 2017-03-27 0.9.3
-=================
+================
 - Add connection error handling to avoid battery drain (WIFI/MQTT Connection issues) Thanks to a broken WIFI and  @amotl.
 
 2017-03-27 0.9.2
-=================
+================
 - Disable 3 of 4 default settings due to bug in homie-esp8266
 
 2017-03-24 0.9.1
-=================
+================
 - Make use of onHomieEvent to ensure a clean disconnect from broker before deepSleep
 - Implement a battery check, create a low battery alarm topic to notify user and make the ESP sleep "forever"
 - All needed settings are now settable via HomieSetting
 - Modularized code
 - Add versioning scheme
 
 2017-03-18 0.9.0
-=================
+================
 - Add JSON output for hiveeyes.org compatibility
 

node-wifi-mqtt-homie-battery/README.rst

@@ -24,9 +24,7 @@ battery lifetime a lot.
 
 .. Todo::
 
-    - Add some scale/temperature calibration curves. Actually not too important, 
-      as some grams don't really matter while we are measuring up to 120kg.
-      But we can ;-)
+    - Describe how to determine scale's temperature compensation values.
 
 
 .. include:: CHANGES.rst

node-wifi-mqtt-homie-battery/node-wifi-mqtt-homie-battery.ino

@@ -52,7 +52,7 @@
 #include <RunningMedian.h>
 
 #define FW_NAME "node-wifi-mqtt-homie-battery"
-#define FW_VERSION "0.9.3"
+#define FW_VERSION "0.9.4"
 const int DEFAULT_SLEEP_TIME = 600;
 
 // PINs
@@ -65,6 +65,8 @@ const int DEFAULT_SLEEP_TIME = 600;
 */
 const long DEFAULT_WEIGHT_OFFSET = 154231; // Load cell zero offset. 
 const float DEFAULT_KILOGRAM_DIVIDER = 21.76;  // Load cell value per kilogram.
+const float DEFAULT_CALIBRATION_TEMPERATURE = 20.0; // Temperature at which the scale has been calibrated for Temperature compensation
+const float DEFAULT_CALIBRATION_FACTOR_GRAM_DEGREE = 0.0; // Calibration factor in gram per degree
 
 /*
  * Scale should be calibrated with a regulated input of 3.3V!
@@ -83,6 +85,8 @@ const float DEFAULT_VCC_ADJUST = 0.13;
 HomieSetting<long> sleepTimeSetting("sleepTime", "SleepTime in seconds (max. 3600s!), default is 60s");
 HomieSetting<long> weightOffsetSetting("weightOffset", "Offset value to zero. Use BeeScale-Calibration.ino to determine.");
 HomieSetting<double> kilogramDividerSetting("kilogramDivider", "Scale value per kilogram. Use BeeScale-Calibration.ino to determine.");
+HomieSetting<double> calibrationTemperatureSetting("calibrationTemperature", "Outside Temperature at which the scale has been calibrated");
+HomieSetting<double> calibrationFactorSetting("calibrationFactor", "Calibration Factor in gram per degree. 0.0 to disable adjustment");
 HomieSetting<double> vccAdjustSetting("vccAdjust", "Calibration value for input voltage. See sketch for details.");
 
 HX711 scale;
@@ -197,6 +201,15 @@ void getWeight() {
   scale.power_down();
 
   weight = WeightSamples.getMedian();
+
+  //temperature compensation
+  Homie.getLogger() << "✔ uncompensated median Weight: " << weight << "g" << endl;
+  float calibrationTemperature = calibrationTemperatureSetting.get();
+  float calibrationFactor = calibrationFactorSetting.get();
+  if (temperature1 < calibrationTemperature) weight = weight+(fabs(temperature1 - calibrationTemperature)*calibrationFactor);
+  if (temperature1 > calibrationTemperature) weight = weight-(fabs(temperature1 - calibrationTemperature)*calibrationFactor);
+  Homie.getLogger() << "✔ compensated median Weight: " << weight << "g" << endl;
+
   weight = weight / 1000 ;      // we want kilogram
 }
 
@@ -352,6 +365,8 @@ void setup() {
       weightOffsetSetting.setDefaultValue(DEFAULT_WEIGHT_OFFSET);
       kilogramDividerSetting.setDefaultValue(DEFAULT_KILOGRAM_DIVIDER);
       vccAdjustSetting.setDefaultValue(DEFAULT_VCC_ADJUST);
+      calibrationTemperatureSetting.setDefaultValue(DEFAULT_CALIBRATION_TEMPERATURE);
+      calibrationFactorSetting.setDefaultValue(DEFAULT_CALIBRATION_FACTOR_GRAM_DEGREE);
 
       //get all measurements *BEFORE* WIFI get's active. This saves around 4s at full mA
       getTemperatures();

node-wifi-mqtt-homie/CHANGES.rst

@@ -12,6 +12,13 @@ in-progress
 - Set some custom settings as default, limited at the moment by issue:
  https://github.com/marvinroger/homie-esp8266/issues/323
 
+2017-03-27 0.9.4
+=================
+- Add temperature compensation in gram per degree
+
+2017-03-27 0.9.3
+=================
+- ommited for the non battery version
 
 2017-03-28 0.9.2
 =================

node-wifi-mqtt-homie/README.rst

@@ -221,13 +221,11 @@ When installing the `UI bundle`_ "``ui_bundle.gz``", the configuration UI will b
 ****
 Todo
 ****
-- Check if HTTP API, SPIFFS and UI configuration options work as described
-- Use the `Homie custom settings`_ feature for storing calibration values
+- Improve documentation at all
 - Document how to determine calibration values (i.e. "Use sketch BeeScale-Calibration to get these values").
   Would it be possible to build it into the main firmware and run it conditionally somehow?
-- Make the `Hiveeyes Backend`_ grok data from Homie devices by using the setting ``mqtt.base_topic`` like::
+- Document how to determine scale's temperature compensation values.
 
-    mqtt.base_topic: hiveeyes/{network}/{gateway}/{node}/homie
 
 .. _Homie custom settings: https://homie-esp8266.readme.io/docs/custom-settings
 

node-wifi-mqtt-homie/node-wifi-mqtt-homie.ino

@@ -44,7 +44,7 @@
 HX711 scale;
 
 #define FW_NAME "node-wifi-mqtt-homie"
-#define FW_VERSION "0.9.2"
+#define FW_VERSION "0.9.4"
 const int DEFAULT_SEND_INTERVAL = 60;
 
 // PINs
@@ -57,6 +57,8 @@ const int DEFAULT_SEND_INTERVAL = 60;
 */
 const float DEFAULT_WEIGHT_OFFSET = 244017.00; // Load cell zero offset. 
 const float DEFAULT_KILOGRAM_DIVIDER = 22.27;  // Load cell value per kilogram.
+const float DEFAULT_CALIBRATION_TEMPERATURE = 20.0; // Temperature at which the scale has been calibrated for Temperature compensation
+const float DEFAULT_CALIBRATION_FACTOR_GRAM_DEGREE = 0.0; // Calibration factor in gram per degree
 unsigned long lastSent = 0;
 
 RunningMedian WeightSamples = RunningMedian(4);
@@ -87,6 +89,8 @@ HomieNode jsonNode("data","__json__");
 HomieSetting<long> sendIntervalSetting("sendInterval", "Interval for measurements in seconds (max. 3600)");
 HomieSetting<long> weightOffsetSetting("weightOffset", "Offset value to zero. Use BeeScale-Calibration.ino to determine.");
 HomieSetting<double> kilogramDividerSetting("kilogramDivider", "Scale value per kilogram. Use BeeScale-Calibration.ino to determine.");
+HomieSetting<double> calibrationTemperatureSetting("calibrationTemperature", "Outside Temperature at which the scale has been calibrated");
+HomieSetting<double> calibrationFactorSetting("calibrationFactor", "Calibration Factor in gram per degree. 0.0 to disable adjustment");
 HomieSetting<double> vccAdjustSetting("vccAdjust", "Calibration value for input voltage. See sketch for details.");
 
 void setupHandler() {
@@ -115,46 +119,55 @@ void getTemperatures() {
 }
 
 void getWeight() {
-  Serial << endl << endl;
-  Serial << "Reading scale, hold on" << endl;
+  Homie.getLogger() << endl << endl;
+  Homie.getLogger() << "Reading scale, hold on" << endl;
   scale.power_up();
   for (int i = 0; i < 4; i++) {
     float WeightRaw = scale.get_units(10);
     yield();
-    Serial << "✔ Raw measurements: " << WeightRaw << "g" << endl;
+    Homie.getLogger() << "✔ Raw measurements: " << WeightRaw << "g" << endl;
     WeightSamples.add(WeightRaw);
     delay(500);                 
     yield();
   }
   scale.power_down();
 
   weight = WeightSamples.getMedian();
+
+  //temperature compensation
+  Homie.getLogger() << "✔ uncompensated median Weight: " << weight << "g" << endl;
+  float calibrationTemperature = calibrationTemperatureSetting.get();
+  float calibrationFactor = calibrationFactorSetting.get();
+  if (temperature1 < calibrationTemperature) weight = weight+(fabs(temperature1 - calibrationTemperature)*calibrationFactor);
+  if (temperature1 > calibrationTemperature) weight = weight-(fabs(temperature1 - calibrationTemperature)*calibrationFactor);
+  Homie.getLogger() << "✔ compensated median Weight: " << weight << "g" << endl;
+
   weight = weight / 1000 ;      // we want kilogram
 }
 
 void getVolt() {
     raw_voltage = ESP.getVcc();
     vcc_adjust = vccAdjustSetting.get();
-    Serial << "Voltage adjust value is: " << vcc_adjust << "V" << endl;
+    Homie.getLogger() << "Voltage adjust value is: " << vcc_adjust << "V" << endl;
     voltage = raw_voltage / 1000 + vcc_adjust;
 }
 
 void loopHandler() {
   if (millis() - lastSent >= sendIntervalSetting.get() * 1000UL || lastSent == 0) {
     getTemperatures();
-    Serial << "Temperature0: " << temperature0 << " °C" << endl;
+    Homie.getLogger() << "Temperature0: " << temperature0 << " °C" << endl;
     temperatureNode0.setProperty("degrees").setRetained(false).send(String(temperature0));
 
-    Serial << "Temperature1: " << temperature1 << " °C" << endl;
+    Homie.getLogger() << "Temperature1: " << temperature1 << " °C" << endl;
     temperatureNode1.setProperty("degrees").setRetained(false).send(String(temperature1));
 
     getWeight();
-    Serial << "Weight: " << weight << " kg" << endl;
+    Homie.getLogger() << "Weight: " << weight << " kg" << endl;
     weightNode.setProperty("kilogram").setRetained(false).send(String(weight));
 
     getVolt();
-    Serial << "Raw Input Voltage: " << raw_voltage << " V" << endl;
-    Serial << "Input Voltage: " << voltage << " V" << endl;
+    Homie.getLogger() << "Raw Input Voltage: " << raw_voltage << " V" << endl;
+    Homie.getLogger() << "Input Voltage: " << voltage << " V" << endl;
     batteryNode.setProperty("volt").setRetained(true).send(String(voltage));
 
     StaticJsonBuffer<200> jsonBuffer;
@@ -164,7 +177,7 @@ void loopHandler() {
     root["Temp2"] = temperature1;
     String values;
     root.printTo(values);
-    Serial << "Json data:" << values << endl;
+    Homie.getLogger() << "Json data:" << values << endl;
     jsonNode.setProperty("__json__").setRetained(false).send(values);
 
     lastSent = millis();
@@ -182,9 +195,11 @@ void setup() {
   /*
   * Can't set more than one value to default, see issue #323
   * https://github.com/marvinroger/homie-esp8266/issues/323
+  */
   weightOffsetSetting.setDefaultValue(DEFAULT_WEIGHT_OFFSET);
   kilogramDividerSetting.setDefaultValue(DEFAULT_KILOGRAM_DIVIDER);
-  */ 
+  calibrationTemperatureSetting.setDefaultValue(DEFAULT_CALIBRATION_TEMPERATURE);
+  calibrationFactorSetting.setDefaultValue(DEFAULT_CALIBRATION_FACTOR_GRAM_DEGREE);
 
   scale.begin(DOUT, PD_SCK);
   scale.set_scale(kilogramDividerSetting.get());  //initialize scale