Add renewed calibration sketch

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

@@ -0,0 +1,284 @@
+/***********************************************************************************************************
+   ESP8266 Calibration code for node-wifi-mqtt-homie[-battery]
+   (c)2014 - 2017 Alexander Wilms
+   https://www.imker-nettetal.de
+
+   GNU GPL v3 License
+   ------------------
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see:
+   <http://www.gnu.org/licenses/gpl-3.0.txt>,
+   or write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+   -------------------------------------------------------------------------
+
+
+  Credits: Marvin Roger for the awesome Homie Framework: https://github.com/marvinroger/homie-esp8266
+
+  Used libraries:
+  HX711:              https://github.com/bogde/HX711
+  RunningMedian:      https://github.com/RobTillaart/Arduino/tree/master/libraries/RunningMedian
+  Homie-esp8266:      https://github.com/marvinroger/homie-esp8266
+  Bounce2:            https://github.com/thomasfredericks/Bounce2
+  ESPAsyncTCP:        https://github.com/me-no-dev/ESPAsyncTCP
+  async-mqtt-client:  https://github.com/marvinroger/async-mqtt-client
+
+  Version 0.9.1
+
+**********************************************************************************************************/
+
+#include <Homie.h>
+#include <OneWire.h>
+#include <DallasTemperature.h>
+#include <Wire.h>
+#include "HX711.h"
+#include <RunningMedian.h>
+
+// PINs
+#define ONE_WIRE_BUS 14
+#define DOUT  13
+#define PD_SCK  12
+
+RunningMedian offsetSamples = RunningMedian(10);
+RunningMedian weightSamples = RunningMedian(10);
+
+HX711 scale;
+ADC_MODE(ADC_VCC);
+
+char c;
+long offset;
+double kilogramDivider;
+long knownWeight;
+
+float weight;
+float temperature0;
+float temperature1;
+float voltage;
+float raw_voltage;
+float vcc_adjust;
+
+OneWire OneWire(ONE_WIRE_BUS);
+DallasTemperature sensors(&OneWire);
+
+void getTemperatures() {
+  sensors.begin();
+  sensors.requestTemperatures(); // Send the command to get temperatures
+  temperature0 = sensors.getTempCByIndex(0);
+  if (temperature0 == -127) {                  //ignore wrong reading
+    delay(100);
+  temperature0 = sensors.getTempCByIndex(0);
+  }
+  temperature1 = sensors.getTempCByIndex(1);
+  if (temperature1 == -127) {                  //ignore wrong reading
+    delay(100);
+  }
+  temperature1 = sensors.getTempCByIndex(1);
+}
+
+
+
+
+void getOffset() {
+  yield();
+    for (int i = 0; i < 10; i++) {
+      Serial.print(".");
+      yield();
+      scale.power_up();
+      float offsetValue = scale.read_average(10);
+      yield();
+      offsetSamples.add(offsetValue);
+      scale.power_down();
+      yield();
+      delay(500);
+      yield();
+    }
+    offset = offsetSamples.getMedian();
+}
+
+
+void getKilogramDivider() {
+    for (int i = 0; i < 10; i++) {
+      Serial.print(".");
+      scale.power_up();
+      float weightValue = scale.read_average(10);
+      yield();
+      weightSamples.add(weightValue);
+      scale.power_down();
+      delay(500);
+      yield();
+    }
+    kilogramDivider = weightSamples.getMedian();
+    kilogramDivider = (kilogramDivider - offset) / knownWeight;
+}
+
+void getVccAdjust() {
+    raw_voltage = ESP.getVcc();
+    vcc_adjust = (3300 - raw_voltage) / 1000;
+
+}
+
+
+void step1() {
+  Serial << endl << endl;
+  Serial << " Step 1: enter the weight of a calibration weight " << endl;
+  Serial << "--------------------------------------------------" << endl;
+  Serial << "  You need a calibration weigt of at least 1000g  " << endl;
+  Serial << "  for Step 3. Please measure it with *another*    " << endl;
+  Serial << "  (hopefully) exact scale and enter it's weight   " << endl;
+  Serial << "  in *gram* here and press ENTER when done...     " << endl; 
+  Serial.flush();
+  while(!Serial.available()) {
+  knownWeight = Serial.parseInt();
+  }
+}
+
+void step2() {
+  Serial << endl << endl;
+  Serial << "               Step 2: tare scale                " << endl;
+  Serial << "-------------------------------------------------" << endl;
+  Serial << "      Remove all weight from the scale and       " << endl;
+  Serial << "        press 1 and ENTER to continue...         " << endl;
+  Serial.flush();
+  while (c!='1') {
+    c = Serial.read();
+    yield();
+    };
+  getOffset();
+  c='x';
+}
+
+void step3() {
+  Serial << endl << endl;
+  Serial << "        Step 3: determine gain per gramm         " << endl;
+  Serial << "-------------------------------------------------" << endl;
+  Serial << "Now put the calibration weight of Step 1 onto the" << endl;
+  Serial << "    scale press 1 and ENTER when you are done    " << endl;
+  Serial.flush();
+  while (c!='1') {
+    c = Serial.read();
+    yield();
+    };
+  getKilogramDivider();
+  c='x';
+}
+
+void step4() {
+  Serial << endl << endl;
+  Serial << "    Step 4: determine calibration temperature"     << endl;
+  Serial << "-------------------------------------------------" << endl;
+  Serial << "     Make sure, that the temperature sensors     " << endl;
+  Serial << "         are attached to the load cell           " << endl;
+  Serial << "     or at least at the same (room) temperature. " << endl;
+  Serial << "        press 1 and ENTER to continue...         " << endl;
+  Serial.flush();
+  while (c!='1') {
+    c = Serial.read();
+    yield();
+  }
+  getTemperatures();
+  c='x';
+}
+
+void step5() {
+  Serial << endl << endl;
+  Serial << "        Step 5: determine volatge adjust         " << endl;
+  Serial << "-------------------------------------------------" << endl;
+  Serial << " The ESP's ADC is not pretty acurate in ADC_VCC  " << endl;
+  Serial << " mode. To determine offset make sure, that the   " << endl;
+  Serial << " input voltage is stable above 3.5 V!            " << endl;
+  Serial << "        press 1 and ENTER to continue...         " << endl;
+  Serial.flush();
+  while (c!='1') {
+    c = Serial.read();
+    yield();
+  }
+  getVccAdjust();
+  c='x';
+}
+
+void printResults() {
+  Serial << endl << endl;
+  Serial << "      Done! Your calculated parameters are:      " << endl;
+  Serial << "-------------------------------------------------" << endl;
+  Serial << "Your entered known weight was: " << knownWeight << "g" << endl;
+  Serial << "weightOffset is:            " << offset << endl;
+  Serial << "kilogramDivider is:         " << kilogramDivider << endl;
+  Serial << "calibration temperature is: " << temperature1 << endl;
+  Serial << "vccAdjust is:               " << vcc_adjust << endl;
+  Serial << "The temperature calibration factor can not be    " << endl;
+  Serial << "determined right here. It has to be evaluated and" << endl;
+  Serial << "calibrated while be scale is productive with real" << endl;
+  Serial << "temperature fluctuations. So use 0.0 for now.    " << endl;
+  Serial << endl << endl;
+}
+
+void testResults() {
+  Serial << "   You can test your calculated settings now!    " << endl;
+  Serial << "        press 1 and ENTER to continue...         " << endl;
+  Serial << "-------------------------------------------------" << endl;
+  Serial.flush();
+  while (c!='1') {
+    c = Serial.read();
+    yield();
+  }
+  getWeight();
+  c='x';
+}
+
+void getWeight() {
+  scale.set_scale(kilogramDivider);  //initialize scale
+  scale.set_offset(offset);    //initialize scale
+  Serial << endl << endl;
+  Serial << "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;
+    weightSamples.add(weightRaw);
+    delay(100);
+    yield();
+  }
+  scale.power_down();
+
+  weight = weightSamples.getMedian();
+
+  weight = weight / 1000 ;      // we want kilogram
+}
+
+
+void setup() {
+  wdt_disable();
+  wdt_enable(300000);
+  WiFi.forceSleepBegin();
+  yield();
+  Serial.begin(115200);
+  Serial << "Scale Adjustment for node-wifi-mqtt-homie / HX711" << endl;
+  Serial << "-------------------------------------------------" << endl;
+  scale.begin(DOUT, PD_SCK);
+  scale.set_scale();
+  scale.set_offset();
+  scale.power_down();
+  step1();
+  step2();
+  step3();
+  step4();
+  step5();
+  printResults();
+}
+
+
+void loop() {
+  testResults();
+  yield();
+  printResults();
+}
+

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
 =================