add sht31 humidity sensor to outdoor station

include/sensor_sht31.cpp

@@ -0,0 +1,130 @@
+//Connect SCL to D1, SDA to D2, GND and 3v3
+#include "sensor_sht31.h"
+
+
+
+Sensor_SHT31::Sensor_SHT31()
+{
+    sht31 = new Adafruit_SHT31();
+}
+
+void Sensor_SHT31::init() //Things to be done during setup()
+{    
+    Serial.println("initializing sht31");
+    if (!sht31->begin(0x44)){
+      Serial.println("#ERROR: SHT31 init fail\n");
+    }else{
+      init_ok=true; //stays false if init failed, sensor will not be read in loop
+    }
+}
+
+//Also called during setup()
+void Sensor_SHT31::setSettings_Temperature(float minchange, unsigned long senddelaymax, unsigned long readdelay)
+{
+    data_temperature.minchange=minchange;
+    data_temperature.senddelaymax=senddelaymax;
+    data_temperature.readdelay=readdelay;
+}
+
+//Also called during setup()
+void Sensor_SHT31::setSettings_Humidity(float minchange, unsigned long senddelaymax, unsigned long readdelay)
+{
+    data_humidity.minchange=minchange;
+    data_humidity.senddelaymax=senddelaymax;
+    data_humidity.readdelay=readdelay;
+}
+
+//Called during setup
+void Sensor_SHT31::advertise(HomieNode& p_sensorNode)
+{
+    sensorNode = &p_sensorNode;
+    sensorNode->advertise("temperature_sht");
+    sensorNode->advertise("humidity_sht");
+    sensorNode->advertise("sht_heater");
+}
+
+void Sensor_SHT31::sensorloop()
+{
+  if (init_ok) {
+    loop_SHT31_temperature();
+    loop_SHT31_humidity();
+  }
+}
+
+void Sensor_SHT31::loop_SHT31_temperature()
+{
+  sensordata &d=data_temperature;
+  bool _changed=false;  
+
+  if (millis() >= (d.lastreadtime+d.readdelay)) {
+    d.value = sht31->readTemperature();
+    if (fabs(d.lastsentvalue-d.value)>=d.minchange){
+      _changed=true;
+    }
+    d.lastreadtime=millis();
+  }
+
+  if (_changed || millis() >= (d.lastsent+d.senddelaymax)) {
+    Serial.print("Sending SHT31_temperature. reason=");
+    if (_changed) Serial.println("change"); else Serial.println("time");
+    
+
+    if (!(isnan(d.value) == 1)){ //success
+      sensorNode->setProperty("temperature_sht").send(String(d.value));
+      Homie.getLogger() << "temperature_sht " << ": " << d.value << endl;    
+      d.lastsentvalue=d.value;
+    }
+
+    d.lastsent=millis();
+  }
+}
+
+void Sensor_SHT31::loop_SHT31_humidity()
+{
+  sensordata &d=data_humidity;
+  bool _changed=false;
+  
+  if (millis() >= (d.lastreadtime+d.readdelay)) {
+    d.value = sht31->readHumidity();
+    checkHeater(d.value);
+    if (fabs(d.lastsentvalue-d.value)>=d.minchange){
+      _changed=true;
+    }
+    d.lastreadtime=millis();
+  }
+
+  if (_changed || millis() >= (d.lastsent+d.senddelaymax)) {
+    Serial.print("Sending SHT31_humidity. reason=");
+    if (_changed) Serial.println("change"); else Serial.println("time");
+
+    if (!(isnan(d.value) == 1)){ //success
+      Homie.getLogger() << "humidity_sht " << ": " << d.value << endl;
+      sensorNode->setProperty("humidity_sht").send(String(d.value));
+      d.lastsentvalue=d.value;
+    }
+    d.lastsent=millis();
+  }
+}
+
+void Sensor_SHT31::checkHeater(float humidity) {
+  
+  bool heaterstatus=sht31->isHeaterEnabled();
+  if (isnan(humidity)==1) { //if sensor cant be read. turn heater on to prevent condensation just in case
+    sht31->heater(true);
+    Serial.println("checkHeater humidity isnan. turned heater on");
+  }else{
+    if (!heaterstatus && humidity>=SHT31_HUMIDITY_HEATERON) {//heater was off and humidity is too high
+      sht31->heater(true);
+      Serial.println("checkHeater humidity too high. turned heater on");
+    }else if(heaterstatus && humidity<=SHT31_HUMIDITY_HEATEROFF) { //heater was on and humidity is low enough
+      sht31->heater(false);
+      Serial.println("checkHeater humidity low enough. turned heater off");
+    }
+  }
+  heaterstatus=sht31->isHeaterEnabled();
+  if (heaterstatus!=last_sent_heaterstatus || millis()<30000) { //changed or just booted
+    sensorNode->setProperty("sht_heater").send(String(heaterstatus));
+    last_sent_heaterstatus=heaterstatus;
+  }
+  
+}

include/sensor_sht31.h

@@ -0,0 +1,46 @@
+#ifndef Sensor_SHT31_H
+#define Sensor_SHT31_H
+
+#include "sensordata.h"
+#include <Homie.h>
+
+#include <Wire.h>
+#include "Adafruit_SHT31.h"
+
+#define SHT31_HUMIDITY_HEATERON 95
+#define SHT31_HUMIDITY_HEATEROFF 85
+
+class Sensor_SHT31
+{
+    
+private:
+    Adafruit_SHT31 *sht31;
+    
+    HomieNode *sensorNode; //reference to HomieNode
+
+    struct sensordata data_temperature; //struct values are changed in setup()
+    struct sensordata data_humidity; //struct values are changed in setup()
+    
+    bool init_ok;
+
+    bool last_sent_heaterstatus;
+
+
+public:
+    Sensor_SHT31();
+
+    void loop_SHT31_temperature();
+    void loop_SHT31_humidity();
+
+    void init();
+    void setSettings_Temperature(float minchange, unsigned long senddelaymax, unsigned long readdelay);
+    void setSettings_Humidity(float minchange, unsigned long senddelaymax, unsigned long readdelay);
+    void advertise(HomieNode& p_sensorNode);
+    void sensorloop();
+
+    void checkHeater(float humidity);
+    
+};
+
+#endif
+

platformio.ini

@@ -43,9 +43,14 @@ build_flags =
     -D SENSOR_TCS34725_COLORTEMP_minchange=100
     -D SENSOR_TCS34725_LUXFACTOR=0.3 #measured with luxmeter. with half tennis ball was 1.7ev less. 1/2^1.7=0,3078
 
-    -D SENSOR_HS1101
-    -D SENSOR_HS1101_PIN=D5
-    -D SENSOR_HS1101_humidity_minchange=10
+    #-D SENSOR_HS1101
+    #-D SENSOR_HS1101_PIN=D5
+    #-D SENSOR_HS1101_humidity_minchange=10
+
+    -D SENSOR_SHT31
+    -D SENSOR_SHT31_humidity_minchange=5
+    -D SENSOR_SHT31_temperature_minchange=0.5
+    
 
     -D SENSOR_ML8511
     -D SENSOR_ML8511_PIN=A0
@@ -72,6 +77,8 @@ lib_deps =
     https://github.com/adafruit/Adafruit_TCS34725#1.3.5
     ArduinoJson@6.16.1 #dependency of homie. using older version because of "ambiguous overload for operator|" error
     Homie@3.0.0
+    adafruit/Adafruit SHT31 Library@^2.2.0
+    SPI
 
 
 #Test

src/main.cpp

@@ -108,6 +108,33 @@ HomieNode sensorNode("sensors", "Sensors","sensors");  //id, name, type
   
 #endif
 
+
+#ifdef SENSOR_SHT31
+  #include "sensor_sht31.cpp"
+  Sensor_SHT31 sensor_sht31;
+
+  #ifndef SENSOR_SHT31_temperature_minchange
+    #define SENSOR_SHT31_temperature_minchange 0.2
+  #endif
+  #ifndef SENSOR_SHT31_temperature_senddelaymax
+    #define SENSOR_SHT31_temperature_senddelaymax 300000
+  #endif
+  #ifndef SENSOR_SHT31_temperature_readdelay
+    #define SENSOR_SHT31_temperature_readdelay 10000
+  #endif
+
+  #ifndef SENSOR_SHT31_humidity_minchange
+    #define SENSOR_SHT31_humidity_minchange 2.0
+  #endif
+  #ifndef SENSOR_SHT31_humidity_senddelaymax
+    #define SENSOR_SHT31_humidity_senddelaymax 10*60*1000
+  #endif
+  #ifndef SENSOR_SHT31_humidity_readdelay
+    #define SENSOR_SHT31_humidity_readdelay 10000
+  #endif
+  
+#endif
+
 #ifdef SENSOR_HS1101
   #include "sensor_hs1101.cpp"
   Sensor_HS1101 sensor_hs1101(SENSOR_HS1101_PIN);
@@ -427,6 +454,12 @@ void setup() {
     sensor_htu21d.setSettings_Humidity(SENSOR_HTU21D_humidity_minchange,SENSOR_HTU21D_humidity_senddelaymax,SENSOR_HTU21D_humidity_readdelay);
   #endif
 
+  #ifdef SENSOR_SHT31
+    sensor_sht31.init();
+    sensor_sht31.setSettings_Temperature(SENSOR_SHT31_temperature_minchange,SENSOR_SHT31_temperature_senddelaymax,SENSOR_SHT31_temperature_readdelay);
+    sensor_sht31.setSettings_Humidity(SENSOR_SHT31_humidity_minchange,SENSOR_SHT31_humidity_senddelaymax,SENSOR_SHT31_humidity_readdelay);
+  #endif
+
 
 
   #ifdef SENSOR_HS1101
@@ -528,6 +561,10 @@ void setup() {
     sensor_htu21d.advertise(sensorNode);
   #endif
 
+  #ifdef SENSOR_SHT31
+    sensor_sht31.advertise(sensorNode);
+  #endif
+
   #ifdef SENSOR_HS1101
     sensor_hs1101.advertise(sensorNode);
   #endif
@@ -609,6 +646,10 @@ void loopHandler() {
     sensor_htu21d.sensorloop();
   #endif
 
+  #ifdef SENSOR_SHT31
+    sensor_sht31.sensorloop();
+  #endif
+
   #ifdef SENSOR_HS1101
     sensor_hs1101.sensorloop();
   #endif