WindSpeed_WindDirection2.ino

#include <math.h>
#define WindSensorPin (32) // The pin location of the anemometer sensor
#define WindVanePin (36) // The pin the wind vane sensor is connected to
#define VaneOffset 0; // define the anemometer offset from magnetic north

int VaneValue; // raw analog value from wind vane
int Direction; // translated 0 - 360 direction
int CalDirection; // converted value with offset applied
int LastValue; // last direction value

volatile bool IsSampleRequired; // this is set true every 2.5s. Get wind speed

volatile unsigned long Rotations; // cup rotation counter used in interrupt routine
volatile unsigned long ContactBounceTime; // Timer to avoid contact bounce in isr

float WindSpeed; // speed miles per hour

////////////////////////////////////////////////////////////////////////////////////////
// This is the function that the interrupt calls to increment the rotation count
void isr_rotation() {

if((millis() - ContactBounceTime) > 15 ) { // debounce the switch contact.
Rotations++;
ContactBounceTime = millis();
}
}

// Convert MPH to Knots
float getKnots(float speed) {
return speed * 0.868976;
}

// Get Wind Direction
void getWindDirection() {

VaneValue = analogRead(WindVanePin);
Direction = map(VaneValue, 0, 1023, 0, 359);
CalDirection = Direction + VaneOffset;

if(CalDirection > 360)
CalDirection = CalDirection - 360;

if(CalDirection < 0)
CalDirection = CalDirection + 360;

}

// Converts compass direction to heading
void getHeading(int direction) {

if(direction < 22)
Serial.print(" N");
else if (direction < 67)
Serial.print(" NE");
else if (direction < 112)
Serial.print(" E");
else if (direction < 157)
Serial.print(" SE");
else if (direction < 212)
Serial.print(" S");
else if (direction < 247)
Serial.print(" SW");
else if (direction < 292)
Serial.print(" W");
else if (direction < 337)
Serial.print(" NW");
else
Serial.print(" N");
}

// converts wind speed to wind strength
void getWindStrength(float speed) {

if(speed < 2)
Serial.println("Calm");
else if(speed >= 2 && speed < 4)
Serial.println("Light Air");
else if(speed >= 4 && speed < 8)
Serial.println("Light Breeze");
else if(speed >= 8 && speed < 13)
Serial.println("Gentle Breeze");
else if(speed >= 13 && speed < 18)
Serial.println("Moderate Breeze");
else if(speed >= 18 && speed < 25)
Serial.println("Fresh Breeze");
else if(speed >= 25 && speed < 31)
Serial.println("Strong Breeze");
else if(speed >= 31 && speed < 39)
Serial.println("Near Gale");
else
Serial.println("RUN");
} 

void setup() 
{

LastValue = 0;
IsSampleRequired = false;


Rotations = 0; // Set Rotations to 0 ready for calculations

Serial.begin(115200);

pinMode(WindSensorPin, INPUT);
attachInterrupt(digitalPinToInterrupt(WindSensorPin), isr_rotation, FALLING);

Serial.println("Davis Anemometer Test");
Serial.println("Speed (MPH)\tKnots\tDirection\tStrength");

}


void loop() {

getWindDirection();

// Only update the display if change greater than 5 degrees.
if(abs(CalDirection - LastValue) > 5) {
LastValue = CalDirection;
}

if(IsSampleRequired) {
// convert to mp/h using the formula V=P(2.25/T)
// V = P(2.25/2.5) = P * 0.9
WindSpeed = Rotations * 0.9;
Rotations = 0; // Reset count for next sample

IsSampleRequired = false;

Serial.print(WindSpeed); Serial.print("\t\t");
Serial.print(getKnots(WindSpeed)); Serial.print("\t");
Serial.print(CalDirection);
getHeading(CalDirection); Serial.print("\t\t");
getWindStrength(WindSpeed);
}
}