Merge branch 'lm_HIH4000' into 'devel'

Improve HIH4000

See merge request berkeleylab/labRemote!181

src/libDevCom/HIH4000.cpp

@@ -4,8 +4,13 @@
 
 #include <cmath>
 
-HIH4000::HIH4000(uint8_t chan, std::shared_ptr<ADCDevice> dev, std::shared_ptr<ClimateSensor> tempSens)
-  : m_adcdev(dev), m_tempSens(tempSens), m_chan(chan)
+
+HIH4000::HIH4000(uint8_t chan, std::shared_ptr<ADCDevice> dev, std::shared_ptr<ClimateSensor> tempSens, float Vsup)
+  : m_adcdev(dev), m_tempSens(tempSens), m_chan(chan), m_Vsup(Vsup), m_calib(false)
+{ }
+
+HIH4000::HIH4000(uint8_t chan, std::shared_ptr<ADCDevice> dev, std::shared_ptr<ClimateSensor> tempSens, float offset, float slope)
+  : m_adcdev(dev), m_tempSens(tempSens), m_chan(chan), m_offset(offset), m_slope(slope), m_calib(true)
 { }
 
 HIH4000::~HIH4000()
@@ -23,11 +28,15 @@ void HIH4000::read()
   m_temperature=m_tempSens->temperature();
   m_humidity = 0.;
   const uint navg = 5;
+  // output voltage
   for(uint i=0;i<navg;i++)
     m_humidity += (float)m_adcdev->read(m_chan);
   m_humidity/=(float)navg;
-  // temperature correction
-  m_humidity=(m_humidity-0.16)/0.0062/(1.0546-0.00216*m_temperature);
+  // sensor humidity
+  if (m_calib) m_humidity = (m_humidity - m_offset)/m_slope;
+  else m_humidity = (m_humidity/m_Vsup-0.16)/0.0062;  
+   // temperature correction
+  m_humidity=m_humidity/(1.0546-0.00216*m_temperature);
 }
 
 float HIH4000::temperature() const

src/libDevCom/HIH4000.h

@@ -7,9 +7,12 @@
 
 //! \brief An implementation of 'ClimateSensor' for reading an HIH4000 sensor
 /**
- * Measures humidity using a HIH4000 sensor connected to one of the analog pins
- * on an Arduino via an ADC intereface.
- * humiditry requires temperature connection: according sensor has to be provided
+ * Measures humidity using a HIH4000 sensor connected to a channel on an ADC device.
+ * Humidity requires temperature connection: according sensor has to be provided.
+ * A better measurement accuracy down to 3.5% RH can be achieved with the pre-calibrated
+ * models HIH4000-003 and -004 with a datasheet providing offset and slope of Vout vs. RH 
+ * calibrated with a supply voltage of 5V. The same supply voltage has to be used for the 
+ * connected HIH4000.
  * HIH4000 specs: https://sensing.honeywell.com/HIH-4000-001-humidity-sensors
  */
 
@@ -20,8 +23,20 @@ public:
    * \param chan The channel number of the analog channel connected to the Pt
    * \param dev The ADCDevice for interfacing with the Adruino or similar - should be calibrated
    *        to return measured voltage as 0...100% of the operational voltage
+   * \param tempSens The Temperature sensor used for the temperature compensation
+   * \param Vsup The supply voltage
    */
-  HIH4000(uint8_t chan, std::shared_ptr<ADCDevice> dev, std::shared_ptr<ClimateSensor> tempSens);
+  HIH4000(uint8_t chan, std::shared_ptr<ADCDevice> dev, std::shared_ptr<ClimateSensor> tempSens, float Vsup = 5.0);
+  
+  /**
+   * \param chan The channel number of the analog channel connected to the Pt
+   * \param dev The ADCDevice for interfacing with the Adruino or similar - should be calibrated
+   *        to return measured voltage as 0...100% of the operational voltage
+   * \param tempSens The Temperature sensor used for the temperature compensation
+   * \param offset The zero offset of Vout vs RH of calibrated sensors at 5V
+   * \param slope The Vout vs RH slope of calibrated sensors at 5V
+   */
+  HIH4000(uint8_t chan, std::shared_ptr<ADCDevice> dev, std::shared_ptr<ClimateSensor> tempSens, float offset, float slope);
   virtual ~HIH4000();
 
   virtual void init();
@@ -41,6 +56,14 @@ private:
   float m_temperature = -273.15;
   //! The humidity recorded in the last reading (defaults to 0)
   float m_humidity = 0.;
+  //! Supply voltage
+  float m_Vsup = 5.;
+  //! Whether the calibration data of a sensor is used
+  bool m_calib = false;
+  //! Zero offset for calibrated sensor
+  float m_offset = 0.85;
+  //! Slope for calibrated sensor
+  float m_slope = 0.03;
   //! ref. to the temperature sensor from which temp. correction is derived
   std::shared_ptr<ClimateSensor> m_tempSens;
 };

src/libDevCom/python.cpp

@@ -6,6 +6,7 @@
 #include "HTS221.h"
 #include "Si7021.h"
 #include "SHT85.h"
+#include "HIH4000.h"
 #include "HIH6130.h"
 
 #include "DeviceCom.h"
@@ -661,6 +662,11 @@ void register_devcom(py::module& m) {
     .def(py::init<std::shared_ptr<I2CCom>>())
     .def("status", &SHT85::status);
   
+  py::class_<HIH4000, PySensor<HIH4000>, ClimateSensor, std::shared_ptr<HIH4000>>(m, "HIH4000")
+    .def(py::init<uint8_t, std::shared_ptr<ADCDevice>, std::shared_ptr<ClimateSensor>>())
+    .def(py::init<uint8_t, std::shared_ptr<ADCDevice>, std::shared_ptr<ClimateSensor>, float>())
+    .def(py::init<uint8_t, std::shared_ptr<ADCDevice>, std::shared_ptr<ClimateSensor>, float, float>());
+  
   py::class_<HIH6130, PySensor_w_status<HIH6130>, ClimateSensor, std::shared_ptr<HIH6130>>(m, "HIH6130")
     .def(py::init<std::shared_ptr<I2CCom>>())
     .def("status", &HIH6130::status);