0.3.2 SHT31

Author: RobTillaart

libraries/SHT31/README.md

@@ -41,8 +41,12 @@ returns false if device address is incorrect or device cannot be reset.
 - **uint16_t readStatus()** details see datasheet and **Status fields** below
 - **uint32_t lastRead()** in milliSeconds since start of program.
 - **reset(bool hard = false)** resets the sensor, soft reset by default. Returns false if fails.
-- **getHumidity()** returns relative humidity in %
-- **getTemperature()** returns temperature in °C
+- **getHumidity()** computes the relative humidity in % based off the latest raw reading, and returns it
+- **getTemperature()** computes the temperature in °C based off the latest raw reading, and returns it
+- **getRawHumidity()** returns the raw two-byte representation of humidity directly from the sensor
+- **getRawTemperature()** returns the raw two-byte representation of temperature directly from the sensor
+
+Note that the temperature and humidity values are recalculated on every call to getHumidity() and getTemperature(). If you're worried about the extra cycles, you should make sure to cache these values or only request them after you've performed a new reading.
 
 
 #### Error interface

libraries/SHT31/SHT31.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: SHT31.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.1
+// VERSION: 0.3.2
 //    DATE: 2019-02-08
 // PURPOSE: Arduino library for the SHT31 temperature and humidity sensor
 //          https://www.adafruit.com/product/2857
@@ -25,6 +25,7 @@
 //
 //  0.3.0   2021-01-04  arduino-ci 
 //  0.3.1   2021-05-27  arduino-lint fixes
+//  0.3.2   2021-08-05  expose raw data from sensor
 
 
 #include "SHT31.h"
@@ -46,12 +47,12 @@
 
 SHT31::SHT31()
 {
-  _addr        = 0;
-  _lastRead    = 0;
-  temperature  = 0;
-  humidity     = 0;
-  _heaterStart = 0;
-  _error       = SHT31_OK;
+  _addr           = 0;
+  _lastRead       = 0;
+  rawTemperature  = 0;
+  rawHumidity     = 0;
+  _heaterStart    = 0;
+  _error          = SHT31_OK;
 }
 
 
@@ -266,10 +267,8 @@ bool SHT31::readData(bool fast)
     }
   }
 
-  uint16_t raw = (buffer[0] << 8) + buffer[1];
-  temperature = raw * (175.0 / 65535) - 45;
-  raw = (buffer[3] << 8) + buffer[4];
-  humidity = raw * (100.0 / 65535);
+  rawTemperature = (buffer[0] << 8) + buffer[1];
+  rawHumidity = (buffer[3] << 8) + buffer[4];
 
   _lastRead = millis();
 

libraries/SHT31/SHT31.h

@@ -2,7 +2,7 @@
 //
 //    FILE: SHT31.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.1
+// VERSION: 0.3.2
 //    DATE: 2019-02-08
 // PURPOSE: Arduino library for the SHT31 temperature and humidity sensor
 //          https://www.adafruit.com/product/2857
@@ -14,7 +14,7 @@
 #include "Wire.h"
 
 
-#define SHT31_LIB_VERSION             (F("0.3.1"))
+#define SHT31_LIB_VERSION             (F("0.3.2"))
 
 
 // fields readStatus
@@ -71,8 +71,10 @@ class SHT31
   bool isHeaterOn();  // is the sensor still heating up?
   bool heatUp() { return isHeaterOn(); };   // will be obsolete in future
 
-  float getHumidity() { return humidity; };
-  float getTemperature() { return temperature; };
+  float getHumidity() { return rawHumidity * (100.0 / 65535); };
+  float getTemperature() { return rawTemperature * (175.0 / 65535) - 45; };
+  uint16_t getRawHumidity() {return rawHumidity ; };
+  uint16_t getRawTemperature() {return rawTemperature; };
 
   // ASYNC INTERFACE
   bool requestData();
@@ -93,8 +95,8 @@ class SHT31
   uint32_t  _lastRequest;   // for async interface
   uint32_t  _heaterStart;
 
-  float humidity;
-  float temperature;
+  uint16_t rawHumidity;
+  uint16_t rawTemperature;
 
   uint8_t _error;
 };

libraries/SHT31/examples/SHT31_rawValues/SHT31_rawValues.ino

@@ -0,0 +1,79 @@
+//
+//    FILE: SHT31_async.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.3.2
+// PURPOSE: demo async interface
+//     URL: https://github.com/RobTillaart/SHT31
+
+
+#include "Wire.h"
+#include "SHT31.h"
+
+#define SHT31_ADDRESS   0x44
+
+uint32_t start;
+uint32_t stop;
+uint32_t cnt;
+
+SHT31 sht;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("SHT31_LIB_VERSION: \t");
+  Serial.println(SHT31_LIB_VERSION);
+
+  Wire.begin();
+  sht.begin(SHT31_ADDRESS);
+  Wire.setClock(100000);
+
+  uint16_t stat = sht.readStatus();
+  Serial.print(stat, HEX);
+  Serial.println();
+  
+  sht.requestData();
+  cnt = 0;
+}
+
+
+void loop()
+{
+  uint16_t rawTemperature;
+  uint16_t rawHumidity;
+
+  if (sht.dataReady())
+  {
+    start = micros();
+    bool success  = sht.readData();   // default = true = fast
+    stop = micros();
+    sht.requestData();                // request for next sample
+
+    Serial.print("\t");
+    Serial.print(stop - start);
+    Serial.print("\t");
+    if (success == false)
+    {
+      Serial.println("Failed read");
+    }
+    else
+    {
+      rawTemperature = sht.getRawTemperature();
+      rawHumidity = sht.getRawHumidity();
+      Serial.print(rawTemperature, HEX);
+      Serial.print(" = ");
+      Serial.print(rawTemperature * (175.0 / 65535) - 45, 1); // This formula comes from page 14 of the SHT31 datasheet
+      Serial.print("°C\t");
+      Serial.print(sht.getRawHumidity(), HEX);
+      Serial.print(" = ");
+      Serial.print(rawHumidity * (100.0 / 65535), 1); // This formula comes from page 14 of the SHT31 datasheet
+      Serial.print("%\t");
+      Serial.println(cnt);
+      cnt = 0;
+    }
+  }
+  cnt++; // simulate other activity
+}
+
+// -- END OF FILE --

libraries/SHT31/library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/SHT31"
   },
-  "version": "0.3.1",
+  "version": "0.3.2",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*"

libraries/SHT31/library.properties

@@ -1,5 +1,5 @@
 name=SHT31
-version=0.3.1
+version=0.3.2
 author=Rob Tillaart <[email protected]>
 maintainer=Rob Tillaart <[email protected]>
 sentence=Arduino library for the SHT31 temperature and humidity sensor

libraries/SHT31/test/unit_test_001.cpp

@@ -61,10 +61,14 @@ unittest(test_begin)
 
   Serial.println(sht.getTemperature());
   Serial.println(sht.getHumidity());
+  Serial.println(sht.getRawTemperature());
+  Serial.println(sht.getRawHumidity());
 
   // default value == 0
-  assertEqual(0, sht.getTemperature());
+  assertEqual(-45, sht.getTemperature());
   assertEqual(0, sht.getHumidity());
+  assertEqual(0, sht.getRawTemperature());
+  assertEqual(0, sht.getRawHumidity());
 }