Merge pull request #5 from Sensirion/InitializeMetaData

Initialize meta data

README.md

@@ -14,6 +14,7 @@ Arduino Library for automatic detection of Sensirion sensors on an I2C Bus. It a
 - SVM4X
 
 ### Sensor Oddities
+- SCD30. This sensor has a particular method of retrieveing measurements, which typically enters a waiting loop until the measurement is ready. To avoid this blocking call, the library uses an alternative method, that sometimes yields I2C errors. These errors are not fatal and can be ignored.
 - SGP41. The SGP41 arduino I2C driver returns raw VOC and NOX values, as opposed to the SEN5X sensors, which internally feed the raw values through [Sensirion's gas index algorithm](https://github.com/Sensirion/gas-index-algorithm) and returns a gas index in the range of [0, 500].
 - STC3X. The STC3X requires a conditioning phase of up to 10 seconds (this library considers 8 sufficient), during which the value of the data points will be UNDEFINED/0.
 - SVM40. The SVM40 Evaluation Kit Board is deprecated and **not** supported by sensor autodetection.
@@ -65,13 +66,13 @@ To use the library, add the following dependencies to your `platformio.ini`'s `l
 
 ```control
 lib_deps =
-    Sensirion UPT I2C Auto Detection
+    Sensirion/Sensirion UPT I2C Auto Detection
 ```
 PlatformIO will automatically fetch the latest version of the dependencies during the build process.
 
 Alternatively, to install this library in your project environment execute the following command in a terminal:
 ```bash
-pio pkg install --library "Sensirion UPT I2C Auto Detection"
+pio pkg install --library "Sensirion/Sensirion UPT I2C Auto Detection"
 ```
 
 To test the default example (`basicUsage`), use the following platformio command from the project's root directory (the one containing the `platformio.ini` file):
@@ -118,7 +119,7 @@ In any case, the following steps are essential.
 
 Include the library:
 ```cpp
-    #include "Sensirion_Sensor_Auto_Detection.h"
+    #include "Sensirion_upt_i2c_auto_detection.h"
 ```
 Instantiate I2CAutoDetector and SensorManager globally (before void setup()):
 

src/ISensor.h

@@ -22,22 +22,10 @@ class ISensor {
     virtual uint16_t start() = 0;
 
     /**
-     * @brief Query sensor whether an initialization step is required or not.
-     *
-     * @param[out] bool true if either a conditioning or initialization command
-     * must be called before measurements are available
+     * @brief Perform extended sensor initialization (if applicable) and
+     * determines sensor metadata.
      */
-    virtual bool requiresInitializationStep() const {
-        return false;
-    };
-
-    /**
-     * @brief Perform extended sensor initialization.
-     * As most sensors don't require this, overriding this method is optional.
-     */
-    virtual uint16_t initializationStep() {
-        return 0;
-    };
+    virtual uint16_t initializationStep() = 0;
 
     /**
      * @brief Get the duration of the conditioning period
@@ -96,12 +84,19 @@ class ISensor {
     }
 
     /**
-     * @brief Get the specific SensorId of the ISensor realization
+     * @brief Get the specific SensorType of the ISensor realization
      *
-     * @return SensorId
+     * @return SensorType
      */
     virtual SensorType getSensorType() const = 0;
 
+    /**
+     * @brief Get the MetaData of the ISensor realization
+     *
+     * @return MetaData
+     */
+    virtual MetaData getMetaData() const = 0;
+
     /**
      * @brief getter method for _NUMBER_OF_ALLOWED_CONSECUTIVE_ERRORS
      */

src/Sensirion_upt_i2c_auto_detection.h

@@ -1,8 +1,8 @@
 #ifndef _SENSIRION_UPT_I2C_AUTO_DETECTION_H_
 #define _SENSIRION_UPT_I2C_AUTO_DETECTION_H_
 
-#include "Sensirion_UPT_Core.h"
 #include "I2CAutoDetector.h"
+#include "Sensirion_UPT_Core.h"
 #include "SensorManager.h"
 #include <Arduino.h>
 

src/SensorStateMachine.cpp

@@ -18,32 +18,30 @@ SensorStateMachine::SensorStateMachine(ISensor* pSensor)
 };
 
 AutoDetectorError SensorStateMachine::_initialize() {
-    if (_sensor->requiresInitializationStep()) {
-        uint16_t error = _sensor->initializationStep();
-        if (error) {
-            char errorMsg[256];
-            errorToString(error, errorMsg, 256);
-            Serial.printf("Failed to perform initialization step: %s\n",
-                          errorMsg);
-            return I2C_ERROR;
-        }
-
-        _lastMeasurementTimeStampMs = millis();
-        _sensorState = SensorStatus::INITIALIZING;
-
-        _sensorSignals.init(_sensor->getNumberOfDataPoints());
+    uint16_t error = _sensor->initializationStep();
+    if (error) {
+        char errorMsg[256];
+        errorToString(error, errorMsg, 256);
+        Serial.printf("Failed to perform initialization step: %s\n", errorMsg);
+        return I2C_ERROR;
+    }
 
-        for (size_t i = 0; i < _sensor->getNumberOfDataPoints(); ++i) {
-            Measurement measurement;
-            _sensorSignals.addMeasurement(measurement);
-        }
+    _sensorSignals.init(_sensor->getNumberOfDataPoints());
+    _measurementIntervalMs = _sensor->getMinimumMeasurementIntervalMs();
+    _lastMeasurementTimeStampMs = millis();
 
+    if (_sensor->getInitializationIntervalMs() > 0) {
+        // SGP4X, SCD4X
+        _sensorState = SensorStatus::INITIALIZING;
     } else {
         _sensorState = SensorStatus::RUNNING;
-        _sensorSignals.init(_sensor->getNumberOfDataPoints());
     }
 
-    _measurementIntervalMs = _sensor->getMinimumMeasurementIntervalMs();
+    for (size_t i = 0; i < _sensor->getNumberOfDataPoints(); ++i) {
+        Measurement measurement;
+        measurement.metaData = _sensor->getMetaData();
+        _sensorSignals.addMeasurement(measurement);
+    }
 
     return NO_ERROR;
 }

src/SensorWrappers/Scd30.cpp

@@ -2,6 +2,11 @@
 #include "SensirionCore.h"
 #include "Sensirion_UPT_Core.h"
 
+Scd30::Scd30(TwoWire& wire) : _wire(wire) {
+    _metaData.deviceType.sensorType = SensorType::SCD30;
+    _metaData.platform = DevicePlatform::WIRED;
+};
+
 uint16_t Scd30::start() {
     _driver.begin(_wire, I2C_ADDRESS);
     return 0;
@@ -28,25 +33,20 @@ uint16_t Scd30::measureAndWrite(Measurement measurements[],
         return error;
     }
 
-    MetaData metaData;
-    metaData.deviceID = _sensorID;
-    metaData.deviceType.sensorType = _sensorType;
-    metaData.platform = DevicePlatform::WIRED;
-
     measurements[0].signalType = SignalType::CO2_PARTS_PER_MILLION;
     measurements[0].dataPoint.t_offset = timeStamp;
     measurements[0].dataPoint.value = co2Concentration;
-    measurements[0].metaData = metaData;
+    measurements[0].metaData = _metaData;
 
     measurements[1].signalType = SignalType::TEMPERATURE_DEGREES_CELSIUS;
     measurements[1].dataPoint.t_offset = timeStamp;
     measurements[1].dataPoint.value = temperature;
-    measurements[1].metaData = metaData;
+    measurements[1].metaData = _metaData;
 
     measurements[2].signalType = SignalType::RELATIVE_HUMIDITY_PERCENTAGE;
     measurements[2].dataPoint.t_offset = timeStamp;
     measurements[2].dataPoint.value = humidity;
-    measurements[2].metaData = metaData;
+    measurements[2].metaData = _metaData;
 
     /* Prepare next reading by querying the dataReadyFlag. We don't need the
      * value of the flag, but the query seems to finalize setting off the
@@ -71,10 +71,11 @@ uint16_t Scd30::initializationStep() {
     }
 
     // SCD30 does not support serial no. retrieval via driver
-    _sensorID = 0;
+    uint64_t sensorID = 0;
     for (size_t i = 0; i < 64; i++) {
-        _sensorID |= (random(2) << i);
+        sensorID |= (random(2) << i);
     }
+    _metaData.deviceID = sensorID;
 
     /* See explanatory comment for measureAndWrite() */
     uint16_t dataReadyFlag;
@@ -83,7 +84,12 @@ uint16_t Scd30::initializationStep() {
 }
 
 SensorType Scd30::getSensorType() const {
-    return _sensorType;
+    return _metaData.deviceType.sensorType;
+    ;
+}
+
+MetaData Scd30::getMetaData() const {
+    return _metaData;
 }
 
 size_t Scd30::getNumberOfDataPoints() const {
@@ -94,10 +100,6 @@ unsigned long Scd30::getMinimumMeasurementIntervalMs() const {
     return 2000;
 }
 
-bool Scd30::requiresInitializationStep() const {
-    return true;
-}
-
 void* Scd30::getDriver() {
     return reinterpret_cast<void*>(&_driver);
 }

src/SensorWrappers/Scd30.h

@@ -8,22 +8,21 @@
 class Scd30 : public ISensor {
   public:
     static const uint16_t I2C_ADDRESS = 0x61;
-    explicit Scd30(TwoWire& wire) : _wire(wire){};
+    explicit Scd30(TwoWire& wire);
     uint16_t start() override;
     uint16_t measureAndWrite(Measurement measurements[],
                              const unsigned long timeStamp) override;
     uint16_t initializationStep() override;
     SensorType getSensorType() const override;
+    MetaData getMetaData() const override;
     size_t getNumberOfDataPoints() const override;
     unsigned long getMinimumMeasurementIntervalMs() const override;
-    bool requiresInitializationStep() const override;
     void* getDriver() override;
 
   private:
     TwoWire& _wire;
     SensirionI2cScd30 _driver;
-    const SensorType _sensorType = SensorType::SCD30;
-    uint64_t _sensorID = 0;
+    MetaData _metaData;
 };
 
 #endif /* _SCD30_H_ */

src/SensorWrappers/Scd4x.cpp

@@ -2,6 +2,11 @@
 #include "SensirionCore.h"
 #include "Sensirion_UPT_Core.h"
 
+Scd4x::Scd4x(TwoWire& wire) : _wire(wire) {
+    _metaData.deviceType.sensorType = SensorType::SCD4X;
+    _metaData.platform = DevicePlatform::WIRED;
+};
+
 uint16_t Scd4x::start() {
     _driver.begin(_wire);
     return 0;
@@ -17,25 +22,20 @@ uint16_t Scd4x::measureAndWrite(Measurement measurements[],
         return error;
     }
 
-    MetaData metaData;
-    metaData.deviceID = _sensorID;
-    metaData.deviceType.sensorType = _sensorType;
-    metaData.platform = DevicePlatform::WIRED;
-
     measurements[0].signalType = SignalType::CO2_PARTS_PER_MILLION;
     measurements[0].dataPoint.t_offset = timeStamp;
     measurements[0].dataPoint.value = static_cast<float>(co2);
-    measurements[0].metaData = metaData;
+    measurements[0].metaData = _metaData;
 
     measurements[1].signalType = SignalType::TEMPERATURE_DEGREES_CELSIUS;
     measurements[1].dataPoint.t_offset = timeStamp;
     measurements[1].dataPoint.value = temp;
-    measurements[1].metaData = metaData;
+    measurements[1].metaData = _metaData;
 
     measurements[2].signalType = SignalType::RELATIVE_HUMIDITY_PERCENTAGE;
     measurements[2].dataPoint.t_offset = timeStamp;
     measurements[2].dataPoint.value = humi;
-    measurements[2].metaData = metaData;
+    measurements[2].metaData = _metaData;
 
     return HighLevelError::NoError;
 }
@@ -52,17 +52,23 @@ uint16_t Scd4x::initializationStep() {
     if (error) {
         return error;
     }
-    _sensorID = 0;
-    _sensorID |=
+    uint64_t sensorID = 0;
+    sensorID |=
         (static_cast<uint64_t>(word0) << 16 * 2) | (word1 << 16) | word2;
 
+    _metaData.deviceID = sensorID;
+
     // Start Measurement
     error = _driver.startPeriodicMeasurement();
     return error;
 }
 
 SensorType Scd4x::getSensorType() const {
-    return _sensorType;
+    return _metaData.deviceType.sensorType;
+}
+
+MetaData Scd4x::getMetaData() const {
+    return _metaData;
 }
 
 size_t Scd4x::getNumberOfDataPoints() const {
@@ -73,8 +79,10 @@ unsigned long Scd4x::getMinimumMeasurementIntervalMs() const {
     return 5000;
 }
 
-bool Scd4x::requiresInitializationStep() const {
-    return true;
+unsigned long Scd4x::getInitializationIntervalMs() const {
+    // Sensor does not produce measurements for ~12s after
+    // startPeriodicMeasurement() is called
+    return 12 * 1000;
 }
 
 void* Scd4x::getDriver() {

src/SensorWrappers/Scd4x.h

@@ -8,22 +8,23 @@
 class Scd4x : public ISensor {
   public:
     static const uint16_t I2C_ADDRESS = 0x62;
-    explicit Scd4x(TwoWire& wire) : _wire(wire){};
+    explicit Scd4x(TwoWire& wire);
     uint16_t start() override;
     uint16_t measureAndWrite(Measurement measurements[],
                              const unsigned long timeStamp) override;
     uint16_t initializationStep() override;
     SensorType getSensorType() const override;
+    MetaData getMetaData() const override;
     size_t getNumberOfDataPoints() const override;
     unsigned long getMinimumMeasurementIntervalMs() const override;
-    bool requiresInitializationStep() const override;
+    // Same as measurement interval
+    unsigned long getInitializationIntervalMs() const override;
     void* getDriver() override;
 
   private:
     TwoWire& _wire;
     SensirionI2CScd4x _driver;
-    const SensorType _sensorType = SensorType::SCD4X;
-    uint64_t _sensorID = 0;
+    MetaData _metaData;
 };
 
 #endif /* _SCD4X_H_ */