accel.ino

/*
  Copyright under GPL
  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/>.

 This file reads data from a BMA020 3-achses acceleration sensor
 and prints it via Serial-library over USB
*/

#include <SPI.h>

#include<stdlib.h>
#include <SD.h>


//led
#define led 9

#define chipSelect 7
#define SDpower 6



#include <Wire.h>

#define ACCELEROMETER 0x38

#define X_OUT1 0x02
#define X_OUT2 0x03

#define Y_OUT1 0x04
#define Y_OUT2 0x05

#define Z_OUT1 0x06
#define Z_OUT2 0x07

#define debug 1 // 0: don't print anything out; 1: print out debugging statements


void setup() {
  // initialize the serial communications:
  Serial.begin(19200);
  Wire.begin();
  //set acc sensor to update data with 1.5KHz
  byte bma_settings = accRead(0x14);
  accWrite((bma_settings|6));
  
  
  
   pinMode(SDpower,OUTPUT);
    digitalWrite(SDpower,LOW);

    delay(1000);
    
     if (!SD.begin(chipSelect)) {
  if (debug) Serial.println("Card failed, or not present");

   // indicate SD problem with fast blink
    while(1) {
      digitalWrite(led,HIGH);
      delay(200);
      digitalWrite(led,LOW);
       delay(200);
    }
  }



}

void loop() {
  // print the sensor values:
  int x = printXVal();
  Serial.print("\t\t");
  int y = printYVal();
  Serial.print("\t\t");
  int z = printZVal();
  Serial.print("\t\t");
  Serial.println();
  // delay before next reading:
  delay(5);
  
  String dataString = "";
  
  
    dataString += x;
    dataString += " ";
    dataString += y;
    dataString += " ";
    dataString += z;



 if(debug) Serial.println(dataString);
  
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  File dataFile = SD.open("datalog.csv", FILE_WRITE);

  // if the file is available, write to it:
  if (dataFile) {
    dataFile.println(dataString);
    dataFile.close();
    // print to the serial port too:
   

  //indicate successful write with short blink
  digitalWrite(led, HIGH);   
  delay(40);
  digitalWrite(led, LOW);

  }
  // if the file isn't open, pop up an error:
  else {
    if (debug) Serial.println("error opening datalog.txt");
  }
  
  delay(100);
  
}

int printXVal() {
  Serial.print("x: ");
  int raw_x1 = (int)accRead(X_OUT1);
  int raw_x2 = (int)accRead(X_OUT2);
  byte  low_bits[8] = {0,0,0,0,0,0,0,0};
  byte high_bits[8] = {0,0,0,0,0,0,0,0};
  uint2bitAry(raw_x1, low_bits);
  uint2bitAry(raw_x2, high_bits);
  int negative_flag = high_bits[7];
  int raw_acceleration = negative_flag<<15;
  if(negative_flag) raw_acceleration >>= 6;
  byte value_ary[9] = {low_bits[6], low_bits[7], high_bits[0], high_bits[1], high_bits[2], high_bits[3], high_bits[4], high_bits[5], high_bits[6]};
  
  int acceleration_value = bitarray2int(value_ary, 9);
  raw_acceleration |= acceleration_value;

  Serial.print(raw_acceleration);
  return raw_acceleration;
}

int printYVal() {
  Serial.print("y: ");
  int raw_y1 = (int)accRead(Y_OUT1);
  int raw_y2 = (int)accRead(Y_OUT2);
  byte  low_bits[8] = {0,0,0,0,0,0,0,0};
  byte high_bits[8] = {0,0,0,0,0,0,0,0};
  uint2bitAry(raw_y1, low_bits);
  uint2bitAry(raw_y2, high_bits);
  int negative_flag = high_bits[7];
  int raw_acceleration = negative_flag<<15;
  if(negative_flag) raw_acceleration >>= 6;
  byte value_ary[9] = {low_bits[6], low_bits[7], high_bits[0], high_bits[1], high_bits[2], high_bits[3], high_bits[4], high_bits[5], high_bits[6]};
  
  int acceleration_value = bitarray2int(value_ary, 9);
  raw_acceleration |= acceleration_value;
  
  Serial.print(raw_acceleration);
  return raw_acceleration;
}

int printZVal() {
  Serial.print("z: ");
  int raw_z1 = (int)accRead(Z_OUT1);
  int raw_z2 = (int)accRead(Z_OUT2);
  byte  low_bits[8] = {0,0,0,0,0,0,0,0};
  byte high_bits[8] = {0,0,0,0,0,0,0,0};
  uint2bitAry(raw_z1, low_bits);
  uint2bitAry(raw_z2, high_bits);
  int negative_flag = high_bits[7];
  int raw_acceleration = negative_flag<<15;
  if(negative_flag) raw_acceleration >>= 6;
  byte value_ary[9] = {low_bits[6], low_bits[7], high_bits[0], high_bits[1], high_bits[2], high_bits[3], high_bits[4], high_bits[5], high_bits[6]};
  
  int acceleration_value = bitarray2int(value_ary, 9);
  raw_acceleration |= acceleration_value;
  
  Serial.print(raw_acceleration);
  return raw_acceleration;
}

void uint2bitAry(unsigned int number, byte* ary) {
  unsigned int original_number = number;
  byte i = 0;
  for (i = 0; i < 8; i++) {
    number = original_number;
    byte bit = (number & (1<<i)) >> i;
    ary[i] = bit;
  }
}

int bitarray2int(byte* ary, byte length) {
  int number = 0;
  byte i = 0;
  for (i = 0; i < length; i++) {
    if( ary[i] ) {
      number += 1<<i;
    }
  }
  return number;
}

byte accRead(byte address) {
  byte val = 0x00;
  Wire.beginTransmission(ACCELEROMETER);
  Wire.write(address);
  Wire.endTransmission();
  Wire.requestFrom(ACCELEROMETER, 1);
  val = Wire.read();
  Wire.endTransmission();
  return val;
}

void accWrite(byte value) {
  Wire.beginTransmission(ACCELEROMETER);
  Wire.write(value);
  Wire.endTransmission();
}


String padInt(int x, int pad) {
  String strInt = String(x);
  
  String str = "";
  
  if (strInt.length() >= pad) {
    return strInt;
  }
  
  for (int i=0; i < (pad-strInt.length()); i++) {
    str += "0";
  }
  
  str += strInt;
  
  return str;
}

String int2string(int x) {
  // formats an integer as a string assuming x is in 1/100ths
  String str = String(x);
  int strLen = str.length();
  if (strLen <= 2) {
    str = "0." + str;
  } else if (strLen <= 3) {
    str = str.substring(0, 1) + "." + str.substring(1);
  } else if (strLen <= 4) {
    str = str.substring(0, 2) + "." + str.substring(2);
  } else {
    str = "-9999";
  }
  
  return str;
}