Documentation

Author: ArminJo

README.md

@@ -55,7 +55,11 @@ An EMA (**Exponential Moving Average**) filter behaves like an RC lowpass filter
 An EMA filter is implemented by e.g. the following statement:
 
 ```c++
-int16_t Lowpass5 += ((InputValue - Lowpass5) >> 5;
+int16_t sLowpass3;
+int16_t Lowpass5;
+...
+sLowpass3 += ((aInputValue - sLowpass3) + (1 << 2)) >> 3; // 1.8 us, alpha = 0.125, cutoff frequency 22.7 Hz @1kHz
+sLowpass5 += ((aInputValue - sLowpass5) + (1 << 4)) >> 5; // 2.5 us, alpha = 1/32 0.03125, cutoff frequency 5.13 Hz @1kHz
 ```
 which takes **2.5 &micro;s on a 16 MHz Arduino Uno**.
 

src/ADCUtils.hpp

@@ -481,7 +481,7 @@ void readAndPrintVCCVoltageMillivolt(Print *aSerial) {
 void readVCCVoltageSimple(void) {
     // use AVCC with (optional) external capacitor at AREF pin as reference
     float tVCC = readADCChannelWithReferenceMultiSamples(ADC_1_1_VOLT_CHANNEL_MUX, DEFAULT, 4);
-    sVCCVoltage = (1023 * 1.1 * 4) / tVCC;
+    sVCCVoltage = (1023 * (((float) ADC_INTERNAL_REFERENCE_MILLIVOLT) / 1000) * 4) / tVCC;
 }
 
 /*

src/HCSR04.h

@@ -35,10 +35,10 @@
 #include <stdint.h>
 
 #define DISTANCE_TIMEOUT_RESULT                   0
-#define US_DISTANCE_DEFAULT_TIMEOUT_MICROS    20000
-#define US_DISTANCE_DEFAULT_TIMEOUT_CENTIMETER  343   // Timeout of 20000L is 3.43 meter
+#define US_DISTANCE_DEFAULT_TIMEOUT_MICROS    20000  // Timeout of 20000L is 3.43 meter
+#define US_DISTANCE_DEFAULT_TIMEOUT_CENTIMETER  343  // Timeout of 20000L is 3.43 meter
 
-#define US_DISTANCE_TIMEOUT_MICROS_FOR_1_METER  5825  // Timeout of 5825 is 1 meter
+#define US_DISTANCE_TIMEOUT_MICROS_FOR_1_METER  5825 // Timeout of 5825 is 1 meter
 #define US_DISTANCE_TIMEOUT_MICROS_FOR_2_METER 11650 // Timeout of 11650 is 2 meter
 #define US_DISTANCE_TIMEOUT_MICROS_FOR_3_METER 17475 // Timeout of 17475 is 3 meter
 

src/HCSR04.hpp

@@ -137,7 +137,7 @@ void initUSDistancePin(uint8_t aTriggerOutEchoInPin) {
 
 /*
  * Start of standard blocking implementation using pulseInLong() since PulseIn gives wrong (too small) results :-(
- * @param aTimeoutMicros timeout of 5825 micros is equivalent to 1 meter, default timeout of 20000 micro seconds is 3.43 meter
+ * @param aTimeoutMicros timeout of 5825 micros is equivalent to 1 meter, default timeout of 20000 micros is 3.43 meter
  * @return 0 / DISTANCE_TIMEOUT_RESULT if uninitialized or timeout happened
  */
 unsigned int getUSDistance(unsigned int aTimeoutMicros) {