#include <Adafruit_BMP085.h>
#include <math.h>
#include "sensors.h"

static Adafruit_BMP085 bmp;

bool sensorsBegin() {
  return bmp.begin();          // uses Wire (already started on D6/D1), addr 0x77
}

float readAbsPressureHpa() {
  return bmp.readPressure() / 100.0f;   // Pa -> hPa
}

float readTemperatureC() {
  return bmp.readTemperature();
}

// Standard barometric reduction to sea level.
float toSeaLevelHpa(float absHpa, float altitudeM) {
  return absHpa / powf(1.0f - (altitudeM / 44330.0f), 5.255f);
}