Improvement on ANALOG_SENSOR (#1326)

* Testing branch

* Added ability (by define) to scale analog sensor, also with number of decimals (it was formerly zero)
Useful when running on batteries to check the battery voltage just 
adding the appropriate resistor

* Reverting DHTSensor.h file

* Trying again to revert DHTSensor.h

* Using macro DEBUG_MSG

* fix method types

code/espurna/config/sensors.h

@@ -99,6 +99,25 @@
 #define ANALOG_DELAY                    0       // Delay between samples in micros
 #endif
 
+//Use the following to perform scaling of raw analog values
+//   scaledRead = ( factor * rawRead ) + offset
+//
+//Please take note that the offset is not affected by the scaling factor
+
+#ifndef ANALOG_FACTOR
+#define ANALOG_FACTOR                    1.0       // Multiply raw reading by this factor
+#endif
+
+#ifndef ANALOG_OFFSET
+#define ANALOG_OFFSET                    0.0       // Add this offset to *scaled* value
+#endif
+
+// Round to this number of decimals
+#ifndef ANALOG_DECIMALS
+#define ANALOG_DECIMALS                  2
+#endif
+
+
 //------------------------------------------------------------------------------
 // BH1750
 // Enable support by passing BH1750_SUPPORT=1 build flag

code/espurna/sensor.ino

@@ -56,6 +56,7 @@ unsigned char _magnitudeDecimals(unsigned char type) {
 
     // Hardcoded decimals (these should be linked to the unit, instead of the magnitude)
 
+    if (type == MAGNITUDE_ANALOG) return ANALOG_DECIMALS;
     if (type == MAGNITUDE_ENERGY ||
         type == MAGNITUDE_ENERGY_DELTA) {
         if (_sensor_energy_units == ENERGY_KWH) return 3;
@@ -414,6 +415,9 @@ void _sensorLoad() {
         AnalogSensor * sensor = new AnalogSensor();
         sensor->setSamples(ANALOG_SAMPLES);
         sensor->setDelay(ANALOG_DELAY);
+        //CICM For analog scaling
+        sensor->setFactor(ANALOG_FACTOR);
+        sensor->setOffset(ANALOG_OFFSET);
         _sensors.push_back(sensor);
     }
     #endif

code/espurna/sensors/AnalogSensor.h

@@ -35,6 +35,16 @@ class AnalogSensor : public BaseSensor {
             _micros = micros;
         }
 
+        void setFactor(double factor) {
+            //DEBUG_MSG(("[ANALOG_SENSOR] Factor set to: %s \n"), String(factor,6).c_str());
+            _factor = factor;
+        }
+
+        void setOffset(double offset) {
+          //DEBUG_MSG(("[ANALOG_SENSOR] Factor set to: %s \n"), String(offset,6).c_str());
+            _offset = offset;
+        }
+
         // ---------------------------------------------------------------------
 
         unsigned int getSamples() {
@@ -45,6 +55,14 @@ class AnalogSensor : public BaseSensor {
             return _micros;
         }
 
+        double getFactor() {
+            return _factor;
+        }
+
+        double getOffset() {
+            return _offset;
+        }
+
         // ---------------------------------------------------------------------
         // Sensor API
         // ---------------------------------------------------------------------
@@ -77,6 +95,7 @@ class AnalogSensor : public BaseSensor {
         }
 
         // Current value for slot # index
+        // Changed return type as moving to scaled value
         double value(unsigned char index) {
             if (index == 0) return _read();
             return 0;
@@ -84,7 +103,9 @@ class AnalogSensor : public BaseSensor {
 
     protected:
 
-        unsigned int _read() {
+        //CICM: this should be for raw values
+        // renaming protected function "_read" to "_rawRead"
+        unsigned int _rawRead() {
             if (1 == _samples) return analogRead(0);
             unsigned long sum = 0;
             for (unsigned int i=0; i<_samples; i++) {
@@ -94,8 +115,28 @@ class AnalogSensor : public BaseSensor {
             return sum / _samples;
         }
 
+        //CICM: and proper read should be scalable and thus needs sign
+        //and decimal part
+        double _read() {
+          //Raw measure could also be a class variable with getter so that can
+          //be reported through MQTT, ...
+          unsigned int rawValue;
+          double scaledValue;
+          // Debugging doubles to string
+          //DEBUG_MSG(("[ANALOG_SENSOR] Started standard read, factor: %s , offset: %s, decimals: %d \n"), String(_factor).c_str(), String(_offset).c_str(), ANALOG_DECIMALS);
+          rawValue = _rawRead();
+          //DEBUG_MSG(("[ANALOG_SENSOR] Raw read received: %d \n"), rawValue);
+          scaledValue = _factor*rawValue  + _offset;
+          //DEBUG_MSG(("[ANALOG_SENSOR] Scaled value result: %s \n"), String(scaledValue).c_str());
+          return scaledValue;
+        }
+
+
         unsigned int _samples = 1;
         unsigned long _micros = 0;
+        //CICM: for scaling and offset, also with getters and setters
+        double _factor = 1.0;
+        double _offset = 0.0;
 
 };