ardupilot/ArducopterNG/Sensors.pde

/*
 www.ArduCopter.com - www.DIYDrones.com
 Copyright (c) 2010.  All rights reserved.
 An Open Source Arduino based multicopter.
 
 File     : Sensors.pde
 Version  : v1.0, Aug 27, 2010
 Author(s): ArduCopter Team
             Ted Carancho (aeroquad), Jose Julio, Jordi Muñoz,
             Jani Hirvinen, Ken McEwans, Roberto Navoni,          
             Sandro Benigno, Chris Anderson
 
 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/>.

* ************************************************************** */

/* ******* ADC functions ********************* */
// Read all the ADC channles
void Read_adc_raw(void)
{
  //int temp;
  
  for (int i=0;i<6;i++)
    AN[i] = adc.Ch(sensors[i]);
}

// Returns an analog value with the offset
int read_adc(int select)
{
  if (SENSOR_SIGN[select]<0)
    return (AN_OFFSET[select]-AN[select]);
  else
    return (AN[select]-AN_OFFSET[select]);
}

void calibrateSensors(void) {
  int i;
  int j = 0;
  byte gyro;
  float aux_float[3];
  
  Read_adc_raw();     // Read sensors data
  delay(5);

  // Offset values for accels and gyros...
  AN_OFFSET[3] = acc_offset_x;                // Accel offset values are taken from external calibration (In Configurator)
  AN_OFFSET[4] = acc_offset_y;
  AN_OFFSET[5] = acc_offset_z;
  aux_float[0] = gyro_offset_roll;
  aux_float[1] = gyro_offset_pitch;
  aux_float[2] = gyro_offset_yaw;

  // Take the gyro offset values
  for(i=0;i<600;i++)
  {
    Read_adc_raw();   // Read sensors
    for(gyro = GYROZ; gyro <= GYROY; gyro++)   
      aux_float[gyro] = aux_float[gyro] * 0.8 + AN[gyro] * 0.2;     // Filtering  
    Log_Write_Sensor(AN[0], AN[1], AN[2], AN[3], AN[4], AN[5], 0);

    delay(5);

    RunningLights(j);   // (in Functions.pde)
    // Runnings lights effect to let user know that we are taking mesurements
    if((i % 5) == 0) j++;
    if(j >= 3) j = 0;
  }
  
  // Switch off all ABC lights
  LightsOff();

  for(gyro = GYROZ; gyro <= GYROY; gyro++)  
    AN_OFFSET[gyro] = aux_float[gyro];    // Update sensor OFFSETs from values read
}

#ifdef UseBMP
void read_baro(void)
{
  float tempPresAlt;
  
  tempPresAlt = float(APM_BMP085.Press)/101325.0;
  //tempPresAlt = pow(tempPresAlt, 0.190284);
  //press_alt = (1.0 - tempPresAlt) * 145366.45;
  tempPresAlt = pow(tempPresAlt, 0.190295);
  if (press_alt == 0)
    press_alt = (1.0 - tempPresAlt) * 4433000;      // Altitude in cm
  else
    press_alt = press_alt * 0.75 + ((1.0 - tempPresAlt) * 4433000)*0.25;  // Altitude in cm (filtered)
}
#endif