/*
 ArduCopter v1.3 - August 2010
 www.ArduCopter.com
 Copyright (c) 2010.  All rights reserved.
 An Open Source Arduino based multicopter.
 
 This program is free software: you can redistribute it and/or modify 
 it under the terms of the GNU General Public License as published by 
 the Free Software Foundation, either version 3 of the License, or 
 (at your option) any later version. 
 
 This program is distributed in the hope that it will be useful, 
 but WITHOUT ANY WARRANTY; without even the implied warranty of 
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
 GNU General Public License for more details. 
 
 You should have received a copy of the GNU General Public License 
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

void ReadSCP1000(void) {
}

#ifdef UseBMP
void read_airpressure(void){
  double x;

  APM_BMP085.Read(); 	//Get new data from absolute pressure sensor
  abs_press = APM_BMP085.Press;
  abs_press_filt = (abs_press); // + 2l * abs_press_filt) / 3l;		//Light filtering
  //temperature = (temperature * 9 + temp_unfilt) / 10;    We will just use the ground temp for the altitude calculation	 

  double p = (double)abs_press_gnd / (double)abs_press_filt;
  double temp = (float)ground_temperature / 10.f + 273.15f;
  x = log(p) * temp * 29271.267f;
  //x = log(p) * temp * 29.271267 * 1000;
  press_alt = (int)(x / 10) + ground_alt;		// Pressure altitude in centimeters
  //  Need to add comments for theory.....
}
#endif

#ifdef UseAirspeed
void read_airspeed(void) {
#if GCS_PROTOCOL != 3 // Xplane will supply the airspeed
  airpressure_raw = ((float)analogRead(AIRSPEED_PIN) * .25) + (airpressure_raw * .75);
  airpressure = (int)airpressure_raw - airpressure_offset;
  airspeed = sqrt((float)airpressure / AIRSPEED_RATIO);
#endif
  airspeed_error = airspeed_cruise - airspeed;
}
#endif

#if BATTERY_EVENT == 1
void read_battery(void)
{
  battery_voltage = BATTERY_VOLTAGE(analogRead(BATTERY_PIN)) * .1 + battery_voltage * .9;
  if(battery_voltage < LOW_VOLTAGE)
    low_battery_event();
}
#endif

#ifdef UseAirspeed
void zero_airspeed(void)
{
  airpressure_raw = analogRead(AIRSPEED_PIN);
  for(int c=0; c < 80; c++){
    airpressure_raw = (airpressure_raw * .90) + ((float)analogRead(AIRSPEED_PIN) * .10);	
  }
  airpressure_offset = airpressure_raw;	
}
#endif