Corrections to battery voltage

Author: Dirk-

WHSR.cpp

@@ -283,9 +283,10 @@ unsigned int WHSR::readVreference(void)
     DoCheckADCMode(REFERENCE_PIN);
     return mySensorValues[REFERENCE_PIN];
 #elif defined(ARDUINO_ARDUINO_NANO33BLE)
-    // TODO: REFERENCE_PIN gibt es nicht beim 33 BLE
-    //return analogRead(REFERENCE_PIN);
-    return 0;
+    // TODO: REFERENCE_PIN not available on 33 BLE
+    // We return the value for 3,26 V
+    // https://docs.arduino.cc/language-reference/en/functions/analog-io/analogReference/
+    return 1011;
 #endif
 }
 
@@ -294,7 +295,7 @@ unsigned int WHSR::readVreference(void)
  * 
  * @return reference voltage [V]
  */
-float WHSR::readVref(void)
+float WHSR::readReferenceVoltage(void)
 {
     float result = (InternalReferenceVoltage * (readVreference() / 1023.0)) / 1000;
 
@@ -312,14 +313,14 @@ float WHSR::readVref(void)
  * 
  * @return battery voltage [V] 
  */
-float WHSR::readBattery(void)
+float WHSR::readBatteryVoltage(void)
 {
 #if defined(ARDUINO_AVR_NANO)
-    float vref = readVref();
+    float vref = readReferenceVoltage();
 
     DoCheckADCMode(BATTERY_ADC);
     float VAdc = (vref / 1023) * mySensorValues[BATTERY_ADC];
-    float result = VAdc * ((ResistorOben + ResistorUnten) / ResistorUnten);
+    float batteryVoltage = VAdc * ((ResistorOben + ResistorUnten) / ResistorUnten);
 
     DebugSerial_print(" B1: ");
     DebugSerial_print(mySensorValues[BATTERY_ADC]);
@@ -329,21 +330,20 @@ float WHSR::readBattery(void)
     DebugSerial_print(result);
     DebugSerial_print("; ");
 #elif defined(ARDUINO_ARDUINO_NANO33BLE)
-    DebugSerial_print("AR_VDD: ");
-    DebugSerial_println(AR_VDD);
+    int batteryADC = analogRead(BATTERY_ADC);
     DebugSerial_print(" BATTERY_ADC: ");
-    DebugSerial_println(analogRead(BATTERY_ADC));
+    DebugSerial_println(batteryADC);
 
   // Voltage calulation with measurements:
-  // 7,11 V => BATTERY_ADC = 338
-  // 6,48 V => BATTERY_ADC = 412
-  //float result = -0.0175 * analogRead(BATTERY_ADC) + 21.805;
-  float result = (338 - analogRead(BATTERY_ADC))/74.0 * 0.63 + 7.11;
-  DebugSerial_print(" Result: ");
-  DebugSerial_println(result);
+  // V1 = 4,66 V => adc1 = 334
+  // V2 = 8,13 V => adc2 = 584
+  // V = (adc - adc1) / (adc2 - adc1) * (V2 - V1) + V1
+  float batteryVoltage = (batteryADC - 334) * 0.01388 + 4.66;
+  DebugSerial_print(" batteryVoltage: ");
+  DebugSerial_println(batteryVoltage);
 #endif
 
-    return (result);
+    return (batteryVoltage);
 }
 
 /**

WHSR.h

@@ -104,10 +104,11 @@
 //
 // Internal Analog Referenz
 //
+#if defined(ARDUINO_AVR_NANO)
 #define STANDARD_INTERNAL_REFERENCE_VOLTAGE 4459L // in mV                           
-                                                  // Kann gemessen/berechnet werden: 
-                                                  //( Vcc / 1024 ) * Asuro::readVreference(void)
-
+#elif defined(ARDUINO_ARDUINO_NANO33BLE)
+#define STANDARD_INTERNAL_REFERENCE_VOLTAGE 3300L // in mV                           
+#endif
 
 // _____________________________________ IO Pins _____________________________________
 
@@ -237,8 +238,8 @@ class WHSR
 	 * ************************************************************************************ */
 
     unsigned int readVreference(void);
-    float readBattery(void);
-    float readVref(void);
+    float readBatteryVoltage(void);
+    float readReferenceVoltage(void);
 
     void readLinesensor(int *data, unsigned char LightStatus);
     void readLinesensor(int *data);

examples/Config/CheckBatteryVoltage/CheckBatteryVoltage.ino

@@ -14,10 +14,10 @@ void setup()
 void loop()
 {
  Serial.print("Vref: ");
-  Serial.println(robo.readVref());
+  Serial.println(robo.readReferenceVoltage());
 
   Serial.print("Vbat: ");
-  Serial.println(robo.readBattery());
+  Serial.println(robo.readBatteryVoltage());
   delay(1000);
 
 }

examples/Sensors/Battery_Vref/Battery_Vref.ino

@@ -22,13 +22,11 @@ void setup()
 
 void loop()
 {
-#if defined(ARDUINO_AVR_NANO)
 	Serial.print("Vref: ");
-	Serial.println(robo.readVref());				// Read reference voltage
-#elif defined(ARDUINO_ARDUINO_NANO33BLE)
-	Serial.println("Vref nicht definiert");			// Not defined
-#endif
+	Serial.println(robo.readReferenceVoltage());
+
 	Serial.print("Vbat: ");
-	Serial.println(robo.readBattery());				// Read battery voltage
-	delay(1000);									// Pause for a second
+	Serial.println(robo.readBatteryVoltage());
+
+	delay(1000);	// Pause for a second
 }

keywords.txt

@@ -27,8 +27,8 @@ ADCWaitForConversion	KEYWORD2
 DoCheckADCMode	KEYWORD2
 
 readVreference	KEYWORD2
-readBattery	KEYWORD2
-readVref	KEYWORD2
+readBatteryVoltage	KEYWORD2
+readReferenceVoltage	KEYWORD2
 readLinesensor	KEYWORD2
 readDistance	KEYWORD2
 readAmbientLight	KEYWORD2