/elec/quadcopter

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

* This program is free software; you can redistribute it and/or modify *

* it under the terms of the GNU License V2.                            *

* 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, version 2 for more details               *

*                                                                      *

* Bare bones ADXL345 i2c example for Arduino 1.0                       *

* by Jens C Brynildsen <http://www.flashgamer.com>                     *

* This version is not reliant of any external lib                      *

* (Adapted for Arduino 1.0 from http://code.google.com/p/adxl345driver)*

*                                                                      *

* Demonstrates use of ADXL345 (using the Sparkfun ADXL345 breakout)    *

* with i2c communication. Datasheet:                                   *

* http://www.sparkfun.com/datasheets/Sensors/Accelerometer/ADXL345.pdf *

* If you need more advanced features such as freefall and tap          *

* detection, check out:                                                *

* https://github.com/jenschr/Arduino-libraries                         *

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

// Cabling for i2c using Sparkfun breakout with an Arduino Uno / Duemilanove:

// Arduino <-> Breakout board

// Gnd      -  GND

// 3.3v     -  VCC

// 3.3v     -  CS

// Analog 4 -  SDA

// Analog 5 -  SLC

// Cabling for i2c using Sparkfun breakout with an Arduino Mega / Mega ADK:

// Arduino <-> Breakout board

// Gnd      -  GND

// 3.3v     -  VCC

// 3.3v     -  CS

// 20       -  SDA

// 21       -  SLC

#include <Wire.h>

#define DEVICE (0x53) // Device address as specified in data sheet 

byte _buff[6];

char POWER_CTL = 0x2D;	//Power Control Register

char DATA_FORMAT = 0x31;

char DATAX0 = 0x32;	//X-Axis Data 0

char DATAX1 = 0x33;	//X-Axis Data 1

char DATAY0 = 0x34;	//Y-Axis Data 0

char DATAY1 = 0x35;	//Y-Axis Data 1

char DATAZ0 = 0x36;	//Z-Axis Data 0

char DATAZ1 = 0x37;	//Z-Axis Data 1

void writeTo(byte address, byte val) {

  Wire.beginTransmission(DEVICE); // start transmission to device 

  Wire.write(address);             // send register address

  Wire.write(val);                 // send value to write

  Wire.endTransmission();         // end transmission

}

// Reads num bytes starting from address register on device in to _buff array

void readFrom(byte address, int num, byte _buff[])

{

  Wire.beginTransmission(DEVICE); // start transmission to device 

  Wire.write(address);             // sends address to read from

  Wire.endTransmission();         // end transmission

  Wire.beginTransmission(DEVICE); // start transmission to device

  Wire.requestFrom(DEVICE, num);    // request 6 bytes from device

  // device may send less than requested (abnormal)

  int i = 0;

  while(Wire.available())

  { 

    _buff[i] = Wire.read();    // receive a byte

    i++;

  }

  Wire.endTransmission();         // end transmission

}

void setup()

{

  // join i2c bus (address optional for master)

  Wire.begin();

  // start serial for output. Make sure you set your Serial Monitor to the

  // same!

  Serial.begin(9600);

  Serial.print("init\n");

  //Put the ADXL345 into +/- 4G range by writing the value 0x01 to the

  //DATA_FORMAT register.

  writeTo(DATA_FORMAT, 0x01);

  //Put the ADXL345 into Measurement Mode by writing 0x08 to the POWER_CTL

  //register.

  writeTo(POWER_CTL, 0x08);

}

void readAccel() {

  //read the acceleration data from the ADXL345

  uint8_t howManyBytesToRead = 6;

  readFrom( DATAX0, howManyBytesToRead, _buff); 

  // each axis reading comes in 10 bit resolution, ie 2 bytes.  Least

  // Significat Byte first!!  thus we are converting both bytes in to one int

  int x = (((int)_buff[1]) << 8) | _buff[0];   

  int y = (((int)_buff[3]) << 8) | _buff[2];

  int z = (((int)_buff[5]) << 8) | _buff[4];

  Serial.print("x: ");

  Serial.print( x );

  Serial.print(" y: ");

  Serial.print( y );

  Serial.print(" z: ");

  Serial.println( z );

}

void loop()

{

  readAccel(); // read the x/y/z tilt

  delay(500); // only read every 0,5 seconds

}