flight/modules/Airspeed/baro_airspeed_etasv3.c

   1 /**
   2  ******************************************************************************
   3  * @addtogroup OpenPilotModules OpenPilot Modules
   4  * @{
   5  * @addtogroup AirspeedModule Airspeed Module
   6  * @brief Communicate with airspeed sensors and return values
   7  * @{
   8  *
   9  * @file       baro_airspeed.c
  10  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
  11  * @brief      Airspeed module, handles temperature and pressure readings from BMP085
  12  *
  13  * @see        The GNU Public License (GPL) Version 3
  14  *
  15  *****************************************************************************/
  16 /*
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 3 of the License, or
  20  * (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful, but
  23  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  24  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  25  * for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License along
  28  * with this program; if not, write to the Free Software Foundation, Inc.,
  29  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  30  */
  31
  32 /**
  33  * Output object: BaroAirspeed
  34  *
  35  * This module will periodically update the value of the BaroAirspeed object.
  36  *
  37  */
  38
  39 #include "openpilot.h"
  40 #include "hwsettings.h"
  41 #include "airspeedsettings.h"
  42 #include "airspeedsensor.h" // object that will be updated by the module
  43 #include "airspeedalarm.h"
  44
  45 #if defined(PIOS_INCLUDE_ETASV3)
  46
  47 #define CALIBRATION_IDLE_MS  2000   // Time to wait before calibrating, in [ms]
  48 #define CALIBRATION_COUNT_MS 2000 // Time to spend calibrating, in [ms]
  49
  50 // Private types
  51
  52 // Private variables
  53
  54 // Private functions
  55
  56 static uint16_t calibrationCount  = 0;
  57 static uint16_t calibrationCount2 = 0;
  58 static uint32_t calibrationSum    = 0;
  59
  60
  61 void baro_airspeedGetETASV3(AirspeedSensorData *airspeedSensor, AirspeedSettingsData *airspeedSettings)
  62 {
  63     // Check to see if airspeed sensor is returning airspeedSensor
  64     airspeedSensor->SensorValue = PIOS_ETASV3_ReadAirspeed();
  65     if (airspeedSensor->SensorValue == (uint16_t)-1) {
  66         airspeedSensor->SensorConnected    = AIRSPEEDSENSOR_SENSORCONNECTED_FALSE;
  67         airspeedSensor->CalibratedAirspeed = 0;
  68         AirspeedAlarm(SYSTEMALARMS_ALARM_ERROR);
  69         return;
  70     }
  71
  72     // only calibrate if no stored calibration is available
  73     if (!airspeedSettings->ZeroPoint) {
  74         AirspeedAlarm(SYSTEMALARMS_ALARM_WARNING);
  75         // Calibrate sensor by averaging zero point value
  76         if (calibrationCount <= CALIBRATION_IDLE_MS / airspeedSettings->SamplePeriod) {
  77             calibrationCount++;
  78             calibrationSum    = 0;
  79             calibrationCount2 = 0;
  80             return;
  81         } else if (calibrationCount <= (CALIBRATION_IDLE_MS + CALIBRATION_COUNT_MS) / airspeedSettings->SamplePeriod) {
  82             calibrationCount++;
  83             calibrationCount2++;
  84             calibrationSum += airspeedSensor->SensorValue;
  85             if (calibrationCount > (CALIBRATION_IDLE_MS + CALIBRATION_COUNT_MS) / airspeedSettings->SamplePeriod) {
  86                 airspeedSettings->ZeroPoint = (int16_t)(((float)calibrationSum) / calibrationCount2);
  87                 AirspeedSettingsZeroPointSet(&airspeedSettings->ZeroPoint);
  88                 calibrationCount  = 0;
  89                 calibrationSum    = 0;
  90                 calibrationCount2 = 0;
  91             }
  92             return;
  93         }
  94     }
  95
  96     // Compute airspeed
  97     airspeedSensor->CalibratedAirspeed = airspeedSettings->Scale * sqrtf((float)abs(airspeedSensor->SensorValue - airspeedSettings->ZeroPoint));
  98     airspeedSensor->SensorConnected    = AIRSPEEDSENSOR_SENSORCONNECTED_TRUE;
  99     AirspeedAlarm(SYSTEMALARMS_ALARM_OK);
 100 }
 101
 102
 103 #endif /* if defined(PIOS_INCLUDE_ETASV3) */
 104
 105 /**
 106  * @}
 107  * @}
 108  */