Forgot to update source code...

firmware/weather_station.ino

@@ -10,7 +10,7 @@
  *       BLINK : I2C ERROR
  *       FLASH : Heartbeat
  *
- * Copyright (C) 2023 M.T. Konstapel https://meezenest.nl/mees
+ * Copyright (C) 2023, 2024 M.T. Konstapel https://meezenest.nl/mees
  *
  * This file is part of weather_station
  *
@@ -42,6 +42,7 @@ SI7021 si7021;
 // Pressure sensor
 #include "i2c_BMP280.h"
 BMP280 bmp280;
+float PRESSURE_OFFSET = 210;   // Calibration of BMP280: offset in Pascal
 
 /**************************/
 /* Configurable variables */
@@ -128,30 +129,33 @@ void ReadSi7021 (void)
     si7021.triggerMeasurement();
     si7021.getHumidity(MeasuredData.Humidity);
     si7021.getTemperature(MeasuredData.Temperature);
-    // Scale for more decimal positions when converted to integer value for ModBus
-    MeasuredData.Humidity *= 100;
-    MeasuredData.Temperature *= 100;
 
-    //If humidity is larger than 80% switch on heater to get more acurate measurement
+    if (MeasuredData.Humidity>100 || MeasuredData.Humidity<0)
-    //Switch off when lower than 78% (hysteresis)
+      MeasuredData.Humidity = 100;
-    if (MeasuredData.Humidity > 80 && !MeasuredData.HeaterStatus) {
+
+    //If humidity is larger than 96% switch on heater to get more acurate measurement and prevent memory offset
+    //Switch off when lower than 94% (hysteresis)
+    if (MeasuredData.Humidity > 96 && !MeasuredData.HeaterStatus) {
       Serial.print(F("Heater on."));
       MeasuredData.HeaterStatus = 1;
       si7021.setHeater(MeasuredData.HeaterStatus);
     }
-    if (MeasuredData.Humidity < 78 && MeasuredData.HeaterStatus) {
+    if (MeasuredData.Humidity < 94 && MeasuredData.HeaterStatus) {
       Serial.print(F("Heater off."));
       MeasuredData.HeaterStatus = 0;
       si7021.setHeater(MeasuredData.HeaterStatus);
     }
-
+    
+    // Scale for more decimal positions when converted to integer value for ModBus
+    MeasuredData.Humidity *= 100;
+    MeasuredData.Temperature *= 100;
 }
 
 // Read BMP280
 void ReadBMP280 (void)
 {
-  MeasuredData.Pressure=0;
+//  MeasuredData.Pressure=0;
-/*
+
   bmp280.awaitMeasurement();
 
   float temperature;
@@ -160,10 +164,20 @@ void ReadBMP280 (void)
   float pascal;
   bmp280.getPressure(pascal);
 
+  pascal = (pascal - PRESSURE_OFFSET) / 10;  // Convert to hPa
+
   MeasuredData.Pressure = pascal;
 
   bmp280.triggerMeasurement();
-*/
+
+  // When humidity is high, the heater of the Si7021 is on. This causes the temperature sensor of the humidity sensor to heat up.
+  // Use temperature sensor of BMP280 instead.
+  if (MeasuredData.HeaterStatus) {
+    bmp280.getTemperature(MeasuredData.Temperature);
+    // Scale for more decimal positions when converted to integer value for ModBus
+    MeasuredData.Temperature *= 100;
+  }
+
 }
 
 int MaxOfArray (int array[], unsigned int length)
@@ -329,7 +343,7 @@ void setup() {
     }
   }
 
-/*  // Initialize BMP280 pressure sensor
+  // Initialize BMP280 pressure sensor
   Serial.print(F("Pressure sensor BMP280 "));
   if (bmp280.initialize())   
     Serial.println(F("found"));
@@ -347,7 +361,7 @@ void setup() {
   // onetime-measure:
   bmp280.setEnabled(0);
   bmp280.triggerMeasurement();
-*/
+
     // Expected ADC values have been defined for various platforms in the
     // library, however your platform may not be included. This code will check
     // if that's the case
@@ -358,6 +372,61 @@ void setup() {
     // resolution, so you'll need to specify it here:
     weatherMeterKit.setADCResolutionBits(10);
 #endif
+
+  // Here we create a struct to hold all the calibration parameters
+  SFEWeatherMeterKitCalibrationParams calibrationParams = weatherMeterKit.getCalibrationParams();
+  
+  // The wind vane has 8 switches, but 2 could close at the same time, which
+  // results in 16 possible positions. Each position has a resistor connected
+  // to GND, so this library assumes a voltage divider is created by adding
+  // another resistor to VCC. Some of the wind vane resistor values are
+  // fairly close to each other, meaning an accurate ADC is required. However
+  // some ADCs have a non-linear behavior that causes this measurement to be
+  // inaccurate. To account for this, the vane resistor values can be manually
+  // changed here to compensate for the non-linear behavior of the ADC
+  calibrationParams.vaneADCValues[WMK_ANGLE_0_0]   = 943;
+  calibrationParams.vaneADCValues[WMK_ANGLE_22_5]  = 828;
+  calibrationParams.vaneADCValues[WMK_ANGLE_45_0]  = 885;
+  calibrationParams.vaneADCValues[WMK_ANGLE_67_5]  = 702;
+  calibrationParams.vaneADCValues[WMK_ANGLE_90_0]  = 785;
+  calibrationParams.vaneADCValues[WMK_ANGLE_112_5] = 404;
+  calibrationParams.vaneADCValues[WMK_ANGLE_135_0] = 460;
+  calibrationParams.vaneADCValues[WMK_ANGLE_157_5] = 82;
+  calibrationParams.vaneADCValues[WMK_ANGLE_180_0] = 91;
+  calibrationParams.vaneADCValues[WMK_ANGLE_202_5] = 64;
+  calibrationParams.vaneADCValues[WMK_ANGLE_225_0] = 185;
+  calibrationParams.vaneADCValues[WMK_ANGLE_247_5] = 125;
+  calibrationParams.vaneADCValues[WMK_ANGLE_270_0] = 285;
+  calibrationParams.vaneADCValues[WMK_ANGLE_292_5] = 242;
+  calibrationParams.vaneADCValues[WMK_ANGLE_315_0] = 628;
+  calibrationParams.vaneADCValues[WMK_ANGLE_337_5] = 598;
+
+  // The rainfall detector contains a small cup that collects rain water. When
+  // the cup fills, the water is dumped and the total rainfall is incremented
+  // by some value. This value defaults to 0.2794mm of rain per count, as
+  // specified by the datasheet
+  calibrationParams.mmPerRainfallCount = 0.2794;
+
+  // The rainfall detector switch can sometimes bounce, causing multiple extra
+  // triggers. This input is debounced by ignoring extra triggers within a
+  // time window, which defaults to 100ms
+  calibrationParams.minMillisPerRainfall = 100;
+
+  // The anemometer contains a switch that opens and closes as it spins. The
+  // rate at which the switch closes depends on the wind speed. The datasheet
+  // states that a wind of 2.4kph causes the switch to close once per second
+  calibrationParams.kphPerCountPerSec = 2.4;
+
+  // Because the anemometer generates discrete pulses as it rotates, it's not
+  // possible to measure the wind speed exactly at any point in time. A filter
+  // is implemented in the library that averages the wind speed over a certain
+  // time period, which defaults to 1 second. Longer intervals result in more
+  // accurate measurements, but cause delay in the measurement
+  calibrationParams.windSpeedMeasurementPeriodMillis = 1000;
+
+  // Now we can set all the calibration parameters at once
+  weatherMeterKit.setCalibrationParams(calibrationParams);
+  
   // Begin weather meter kit
   weatherMeterKit.begin();
 
@@ -396,6 +465,10 @@ void loop() {
     mb.Ireg (SensorHumidityIreg, MeasuredData.Humidity);
     mb.Ireg (SensorPressureIreg, MeasuredData.Pressure);
 
+    // Debug wind vane
+    //Serial.print(F("\n    Measured ADC: "));
+    //Serial.print(analogRead(windDirectionPin));
+
     digitalWrite(LED_BUILTIN, LOW);  // LED as heartbeat