Hallo!
..steh grad voll am Schlauch, wegen:
Du darfst nicht mit Absolutwerten rechnen, sondern kalibrierst deinen Sensor in den ersten paar sek nach Programmstart mit dem Durchschnittswert, ab dann nimmst du immer nur die Differenzen zu diesen Referenzwerten.
Das Teil funktioniert doch mit Gravity, hab zum Kalibrieren. einen Würfel und den Sketch:
/*****************************************************************************/
// Function: To calibrate the parameters and it will recommend parameter
// setting and print to the serial monitor.So the values of the
// marco definitions in the ADXL335.h should be modified.
// Hardware: Grove - 3-Axis Analog Accelerometer
// Arduino IDE: Arduino-1.0
// Author: Frankie.Chu
// Date: Jan 11,2013
// Version: v1.0
// by www.seeedstudio.com
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
//
/*******************************************************************************/
#include "ADXL335.h"
int zero_x;
int zero_y;
int zero_z;
int max_x,max_y,max_z;//when 1g
float sensitivity;
ADXL335 accelerometer;
void setup()
{
Serial.begin(9600);
accelerometer.begin();
int x,y,z;
for(int i = 0;i < 20;i ++)accelerometer.getXYZ(&x,&y,&z);
Serial.println("The calibration starts: ");
Serial.println("First, make sure that Z-axis direction is straight up");
Serial.println("please type any charactor if you are ready");
while(Serial.available() == 0);
delay(100);
while(Serial.available() > 0)Serial.read();
calibrate(&x,&y,&z);
zero_x = x;
zero_y = y;
max_z = z;
Serial.println("Second, make sure that X-axis direction is straight up");
Serial.println("please type any charactor again if you are ready");
while(Serial.available() == 0);
delay(100);
while(Serial.available() > 0)Serial.read();
calibrate(&x,&y,&z);
zero_z = z;
float zero_xv,zero_yv,zero_zv;
zero_xv = (float)zero_x*ADC_REF/ADC_AMPLITUDE;
zero_yv = (float)zero_y*ADC_REF/ADC_AMPLITUDE;
zero_zv = (float)zero_z*ADC_REF/ADC_AMPLITUDE;
sensitivity =(float)(max_z - zero_z)*ADC_REF/ADC_AMPLITUDE;
Serial.print("ZERO_X = ");
Serial.println(zero_xv);
Serial.print("ZERO_Y = ");
Serial.println(zero_yv);
Serial.print("ZERO_Z = ");
Serial.println(zero_zv);
Serial.print("SENSITIVITY = ");
Serial.println(sensitivity,2);
Serial.println("please modified the macro definitions with these results in ADXL335.h");
}
void loop()
{
}
void calibrate(int* _x,int* _y,int* _z)
{
int x,y,z;
int sum_x,sum_y,sum_z;
accelerometer.getXYZ(&x,&y,&z);
float ax,ay,az;
accelerometer.getAcceleration(&ax,&ay,&az);
if((abs(ax) < 0.06)&&(abs(ay) < 0.06))
{
*_x = x;
*_y = y;
*_z = z;
}
else if((abs(ax) < 0.06)&&(abs(az) < 0.06))
{
*_x = x;
*_y = y;
*_z = z;
}
else if((abs(az) < 0.06)&&(abs(ay) < 0.06))
{
*_x = x;
*_y = y;
*_z = z;
}
else Serial.println("calibrate error");
}
..nach dem Eintragen der Offsetwerte in ADXL335.h hab ich dann stabile G-0 an allen 3 Achsen,
sofern die ausrichtung vom Sensor passt.
Da sich ja die Y- Achse aus der Z-X Kalibrierung ergibt, kann doch eine Mittelwertbildung keine korrekten Werte liefern ?
mfg Martin
Temperatursensor liegt schon bereit, da mache ich mich die Tage dran zu schaffen